Consumer medicine information

Minax XL

Metoprolol succinate

BRAND INFORMATION

Brand name

Minax XL

Active ingredient

Metoprolol succinate

Schedule

S4

 

Consumer medicine information (CMI) leaflet

Please read this leaflet carefully before you start using Minax XL.

What is in this leaflet

This leaflet answers some common questions about MINAX XL.

It does not contain all the available information. It does not take the place of talking to your doctor or pharmacist.

All medicines have benefits and risks. Your doctor has weighed the risks of you taking MINAX XL against the benefits expected for you.

If you have any concerns about taking this medicine, talk to your doctor or pharmacist.

Keep this leaflet with your medicine. You may need to read it again.

What MINAX XL is used for

MINAX XL belongs to a group of medicines called beta-blockers.

It works by affecting the body's response to some nerve impulses, especially in the heart. As a result, it decreases the heart's need for blood and oxygen and therefore reduces the amount of work the heart has to do. It also helps the heart to beat more regularly.

MINAX XL is used to treat heart failure - increase survival, reduce hospitalisation and improve symptoms. It is used in combination with other medicines to treat your condition.

Ask your doctor if you have any questions about why this medicine has been prescribed for you. Your doctor may have prescribed it for another reason.

Before you take MINAX XL

When you must not take it

Do not take MINAX XL if you have an allergy to:

  • any medicine containing metoprolol succinate
  • any of the ingredients listed at the end of this leaflet
  • any other beta-blockers.

Some of the symptoms of an allergic reaction may include

  • shortness of breath
  • wheezing or difficulty breathing
  • swelling of the face, lips, tongue or other parts of the body
  • rash, itching or hives on the skin

Do not take this medicine if you have or have had asthma (difficulty in breathing, wheezing and coughing), bronchitis or other lung problems in the past.

Do not take MINAX XL if you have the following conditions:

  • a history of allergic problems, including hayfever
  • a very slow heart beat (less than 45-50 beats/minute)
  • a severe blood vessel disorder causing poor circulation in the arms and legs
  • certain other heart conditions
  • phaeochromocytoma (a rare tumour of the adrenal gland) which is not being treated with other medicines
  • low blood pressure (hypotension)
  • receiving/having emergency treatment for shock or severely low blood pressure.

Do not give this medicine to children. Safety and effectiveness in children have not been established.

Do not take this medicine after the expiry date printed on the pack or if the packaging is torn or shows signs of tampering. If it has expired or is damaged, return it to your pharmacist for disposal.

If you are not sure whether you should start taking this medicine, talk to your doctor.

Before you start to take it

Tell your doctor if you have allergies to any other medicines, foods, preservatives or dyes.

Tell your doctor if you have or have had any of the following medical conditions:

  • asthma or other lung problems, even if you have had them in the past
  • allergic problems, including hayfever
  • diabetes
  • very slow heart beat (less than 45-50 beats/minute)
  • severe blood vessel disorder causing poor circulation in the arms and legs
  • liver problems
  • kidney problems
  • certain types of angina
  • any other heart problems
  • phaeochromocytoma, a rare tumour of the adrenal gland
  • hyperthyroidism (an overactive thyroid gland)

Tell your doctor if you are pregnant or intend to become pregnant. Like most beta-blocker medicines, MINAX XL is not recommended for use during pregnancy.

Tell your doctor if you are breastfeeding or plan to breast-feed. The active ingredient in MINAX XL passes into breast milk and there is a possibility that the breast-fed baby may be affected.

If you have not told your doctor about any of the above, tell him/her before you start taking MINAX XL.

Taking other medicines

Tell your doctor or pharmacist if you are taking any other medicines, including any that you get without a prescription from a pharmacy, supermarket or health food shop.

Some medicines and MINAX XL may interfere with each other. These include:

  • other beta-blocker medicines, including beta-blocker eye drops
  • calcium channel blockers or calcium antagonists, medicines used to treat high blood pressure and angina, for example verapamil and diltiazem
  • medicines used to treat high blood pressure, for example clonidine, hydralazine and prazosin
  • medicines used to treat abnormal or irregular heartbeat, for example, amiodarone, disopyramide and quinidine
  • medicines used to treat arthritis, pain, or inflammation, for example indomethacin and ibuprofen
  • digoxin, a medicine used to treat heart failure
  • medicines used to treat diabetes
  • medicines used to treat bacterial infections, for example rifampicin
  • anti-inflammatory drugs
  • cimetidine, a medicine used to treat stomach ulcers
  • medicines used to treat depression
  • warfarin, a medicine used to prevent blood clots
  • monoamine-oxidase inhibitors (MAOIs)

These medicines may be affected by MINAX XL or may affect how well it works. You may need different amounts of your medicines, or you may need to take different medicines. Your doctor will advise you.

Your doctor and pharmacist have more information on medicines to be careful with or avoid while taking this medicine.

If you have not told your doctor about any of these things, tell them before you taken any MINAX XL.

How to take MINAX XL

Follow all directions given to you by your doctor and pharmacist carefully. They may differ from the information contained in this leaflet.

If you do not understand the instructions on the box, ask your doctor or pharmacist for help.

How much to take

The usual starting dose is half a 23.75 mg or a whole 23.75 mg tablet once a day for one to two weeks. The dose is then usually doubled every second week up to a maximum dose of 190 mg once daily or to the highest tolerated dose.

How to take it

Halved tablet:

Break the tablet into half. Swallow halved tablet whole with a full glass of water.

Whole tablet:

Swallow the tablets whole with a full glass of water.

Do not crush or chew the tablets.

Follow your doctor's instructions carefully. If you are taking other medicines your doctor may need to change the dose of them to obtain the best results for you.

DO NOT STOP TAKING MINAX XL TABLETS SUDDENLY. The dose needs to be reduced slowly over at least 14 days to make sure your condition does not get worse. Your doctor will tell you how to reduce the dose.

When to take it

Take your medicine at about the same time each day, preferably together with the morning meal. Taking it at the same time each day will have the best effect. It will also help you remember when to take it.

How long to take it

Continue taking your medicine for as long as your doctor tells you to. This medicine helps to control your condition, but does not cure it. It is important to keep taking your medicine even if you feel well.

DO NOT STOP TAKING MINAX XL TABLETS SUDDENLY. The dose needs to be reduced slowly over 7 to 14 days to make sure that your condition does not get worse. Your doctor will tell you how to gradually reduce the dose before stopping completely.

If you forget to take it

If you forgot to take a dose of MINAX XL, skip the dose you missed and take your next dose when you are meant to.

Do not take a double dose to make up for the dose that you missed.

If you are not sure what to do, ask your doctor or pharmacist.

If you have trouble remembering when to take your medicine, ask your pharmacist for some hints.

If you take too much (overdose)

Immediately telephone your doctor or the Poisons Information Centre (telephone 13 11 26) for advice, or go to Accident and Emergency at the nearest hospital, if you think that you or anyone else may have taken too much MINAX XL. Do this even if there are no signs of discomfort or poisoning. You may need urgent medical attention.

If you take too many MINAX XL tablets, your blood pressure may drop too far. You will feel faint or may faint and your heart rate will also slow down. You may also have nausea, vomiting and shortness of breath. In extreme cases, serious heart and lung problems may occur.

While you are taking MINAX XL

Things you must do

If you are about to be started on any new medicine, remind your doctor and pharmacist that you are taking MINAX XL.

Tell any other doctors, dentists and pharmacists who treat you that you are taking this medicine.

If you plan to have surgery (even at the dentist) that needs an anaesthetic, tell your doctor or dentist that you are taking MINAX XL.

If you become pregnant while taking this medicine, tell your doctor immediately.

If you have a severe allergic reaction to foods, medicines or insect stings, tell your doctor immediately. If you have a history of allergies, there is a chance that MINAX XL may cause allergic reactions to be worse and harder to treat.

If you feel light-headed, dizzy or faint when getting out of bed or standing up, get up slowly. You may feel light-headed or dizzy when you begin to take MINAX XL. This is because your blood pressure has fallen suddenly.

Standing up slowly, especially when you get up from bed or chairs, will help your body get used to the change in position and blood pressure. If this problem gets worse or continues, talk to your doctor.

If you feel a worsening of your condition in the early stages of taking MINAX XL, tell your Dr immediately. Some people may experience an apparent worsening of their condition in the early stages of treatment with MINAX XL. It is important to tell your doctor if this happens to you, although it is usually temporary. If your condition continues to worsen, you should see your doctor as soon as possible.

Make sure you drink enough water during exercise and hot weather when you are taking MINAX XL, especially if you sweat a lot. If you do not drink enough water while taking MINAX XL, you may feel faint or light-headed or sick. This is because your blood pressure is dropping too much. If you continue to feel unwell, tell your doctor.

If you are being treated for diabetes, make sure you check your blood sugar level regularly and report any changes to your doctor. MINAX XL may change how well your diabetes is controlled. It may also cover up some of the symptoms of low blood sugar (hypoglycaemia). MINAX XL may increase the time your body takes to recover from low blood sugar. Your doses of diabetic medicines, including insulin, may need to change.

If you are about to have any blood tests, tell your doctor that you are taking this medicine. It may interfere with the results of some tests.

Keep all of your doctor's appointments so that your progress can be checked.

Things you must not do

Do not take MINAX XL to treat any other complaints unless your doctor tells you to.

Do not give your medicine to anyone else, even if they have the same condition as you.

Do not stop taking your medicine or change the dosage without checking with your doctor. Your doctor may want you to gradually reduce the amount of MINAX XL you are taking before stopping completely. This may help reduce the possibility of your condition worsening or other heart complications occurring.

Things to be careful of

Be careful driving or operating machinery until you know how MINAX XL affects you. As with other beta-blocker medicines, MINAX XL may cause dizziness, light-headedness, tiredness, or drowsiness in some people. Make sure you know how you react to MINAX XL before you drive a car, operate machinery, or do anything else that could be dangerous if you are dizzy or light-headed.

Be careful when drinking alcohol while you are taking this medicine. If you drink alcohol, dizziness or light-headedness may be worse.

Dress warmly during cold weather, especially if you will be outside for a long time (for example when playing winter sports). MINAX XL, like other beta-blocker medicines, tends to decrease blood circulation in the skin, fingers and toes. It may make you more sensitive to cold weather, especially if you have circulation problems.

Side effects

Tell your doctor or pharmacist as soon as possible if you do not feel well while you are taking MINAX XL.

If you get any side effects, do not stop taking MINAX XL without first talking to your doctor.

All medicines can have side effects. Sometimes they are serious, most of the time they are not. You may need medical attention if you get some of the side effects.

If you are over 65 years of age you may have an increased chance of getting side effects.

Ask your doctor or pharmacist to answer any questions you may have.

Tell your doctor or pharmacist if you notice any of the following and they worry you:

  • headache, tiredness, drowsiness, weakness, or lack of energy
  • aches and pains, painful joints
  • nausea (feeling sick), vomiting
  • stomach upset, diarrhoea or constipation, weight gain
  • dry mouth, changes in taste sensation
  • difficulty sleeping, nightmares
  • mood changes
  • confusion, short-term memory loss, inability to concentrate
  • increased sweating, runny or blocked nose
  • hair loss.

The above side effects are usually mild.

Tell your doctor as soon as possible if you notice any of the following:

  • dizziness, light headedness or fainting especially on standing up, which may be a sign of low blood pressure
  • tingling or "pins and needles"
  • coldness, burning, numbness or pain in the arms and/or legs
  • skin rash or worsening of psoriasis
  • sunburn happening more quickly than usual
  • abnormal thinking or hallucinations
  • buzzing or ringing in the ears, deafness
  • irritated eyes or blurred vision
  • problems with sexual function
  • constant "flu-like" symptoms with tiredness or lack of energy
  • unusual bleeding or bruising.

The above list includes serious side effects that may require medical attention. Serious side effects are rare.

If any of the following happen, tell your doctor immediately or go to Accident and Emergency at your nearest hospital:

  • shortness of breath, being less able to exercise
  • swelling of the ankles, feet or legs
  • chest tightness, wheezing, noisy breathing, difficulty breathing
  • chest pain, changes in heart rate or palpitations
  • swelling of the face, lips, tongue or throat which may cause difficulty in swallowing or breathing, which may be signs of a serious allergic reaction
  • yellowing of the skin or eyes (jaundice), generally feeling unwell.

The above list includes very serious side effects. You may need urgent medical attention or hospitalisation. These side effects are very rare.

Other side effects not listed here may occur in some patients. Tell your doctor or pharmacist if you notice anything that is making you feel unwell.

Do not be alarmed by this list of possible side effects.

You may not experience any of them.

After taking MINAX XL

Storage

Keep your tablets in the pack until it is time to take them. If you take the tablets out of the pack they may not keep well.

Keep your tablets in a cool dry place where the temperature stays below 25°C.

Do not store MINAX XL or any other medicine in the bathroom or near a sink. Do not leave it on a window sill or in the car. Heat and dampness can destroy some medicines.

Keep it where children cannot reach it. A locked cupboard at least one-and-a-half metres above the ground is a good place to store medicines.

Disposal

If your doctor tells you to stop taking this medicine or the expiry date has passed, ask your pharmacist what to do with any medicine that is left over.

Product description

What it looks like

MINAX XL modified release tablets are available in four (4) different product strengths:

  • 23.75 mg: White to off-white, round shaped, biconvex film coated tablets debossed with "M" on one side of break line on one side of the tablet and "MT1" on other side of the tablet. Available in blister packs 15 tablets.
  • 47.5 mg: White to off-white, oval shaped, biconvex film coated tablet debossed with "M" on one side of break line on one side of the tablet and "MT2" on other side of the tablet. Available in blister packs of 30 tablets.
  • 95 mg: White to off-white, oval shaped, biconvex film coated tablet debossed with "M" on one side of break line on one side of the tablet and "MT3" on other side of the tablet. Available in blister packs 30 tablets.
  • 190 mg: White to off-white, oval shaped, biconvex film coated tablet debossed with "M" on one side of break line on one side of the tablet and "MT4" on other side of the tablet. Available in blister packs 30 tablets.

Ingredients

MINAX XL contains 23.75 mg, 47.5 mg, 95 mg or 190 mg of metoprolol succinate as the active ingredient.

It also contains the following inactive ingredients:

  • microcrystalline cellulose
  • ethylcellulose
  • macrogol 400
  • hypromellose
  • colloidal anhydrous silica
  • macrogol 6000
  • sodium stearylfumarate
  • OPADRY II complete film coating system 32K58900 WHITE

MINAX XL contains lactose.

Supplier

MINAX XL is supplied in Australia by:

Alphapharm Pty Ltd trading as Viatris
Level 1, 30 The Bond
30-34 Hickson Road
Millers Point NSW 2000
www.viatris.com.au
Phone: 1800 274 276

Australian registration numbers:

MINAX XL 23.75 mg:
AUST R 205151

MINAX XL 47.5 mg:
AUST R 205149

MINAX XL 95 mg:
AUST R 205148

MINAX XL 190 mg:
AUST R 205150

This leaflet was prepared in September 2023.

MINAX® is a Viatris company trade mark

MINAX XL_cmi\Sep23/00

Published by MIMS November 2023

BRAND INFORMATION

Brand name

Minax XL

Active ingredient

Metoprolol succinate

Schedule

S4

 

1 Name of Medicine

Metoprolol succinate.

2 Qualitative and Quantitative Composition

Each Minax XL modified release tablet contains, 23.75 mg, 47.5 mg, 95 mg, 190 mg metoprolol succinate as the active ingredient.

Excipients with known effect.

Lactose.
For the full list of excipients, see Section 6.1 List of Excipients.

3 Pharmaceutical Form

Minax XL 23.75 tablets (23.75 mg).

White to off-white, round shaped, biconvex film coated tablets debossed with "M" on one side of break line on one side of the tablet and "MT1" on other side of the tablet.

Minax XL 47.5 tablets (47.5 mg).

White to off-white, oval shaped, biconvex film coated tablets debossed with "M" on one side of break line on one side of the tablet and "MT2" on other side of the tablet.

Minax XL 95 tablets (95 mg).

White to off-white, oval shaped, biconvex film coated tablets debossed with "M" on one side of break line on one side of the tablet and "MT3" on other side of the tablet.

Minax XL 190 tablets (190 mg).

White to off-white, oval shaped, biconvex film coated tablets debossed with "M" on one side of break line on one side of the tablet and "MT4" on other side of the tablet.

4 Clinical Particulars

4.1 Therapeutic Indications

Stable, chronic heart failure as an adjunct to other heart failure therapy.

4.2 Dose and Method of Administration

Minax XL has not been established to be clinically equivalent to immediate release forms of metoprolol, and should not be used for treatment of conditions other than stable, chronic heart failure.
Minax XL is recommended for once daily treatment and is preferably taken together with the morning meal. The tablets may be broken in half. Minax XL tablets should be swallowed with liquid and should not be chewed or crushed.
The dose of Minax XL should be individually adjusted in patients with chronic heart failure stabilised on other heart failure treatment.
It is recommended that patients be titrated from an initial low dose in accordance with the following titration schedule (see Table 1).
The patient should be carefully evaluated at each dose level with regard to tolerability. If the patient experiences hypotension a decreased dose of concomitant heart failure medication may be necessary. Initial hypotension does not necessarily mean that the dose cannot be tolerated during chronic treatment but the patient should be kept at the lower dose until their blood pressure has stabilised.
Some patients may experience an initial, usually transient, worsening of the symptoms and signs of heart failure when starting treatment with Minax XL. If this occurs, the patient should be monitored very closely and the dose of Minax XL should be reduced if symptoms continue to worsen. Minax XL should not be ceased abruptly due to the risk of rebound hypertension and tachycardia. If treatment is to be discontinued, it should be reduced gradually (see Section 4.4 Special Warnings and Precautions for Use).

Impaired renal and hepatic function.

Dose adjustment is not needed in patients with impaired renal function.
Dose adjustment is normally not needed in patients suffering from liver cirrhosis because metoprolol is low protein binding (5-10%). When there are signs of serious impairment of liver function (e.g. patients who have had a shunt operation), a dose reduction should be considered.

Elderly.

Dose adjustment is not needed in the elderly.

Children.

There is limited experience with Minax XL treatment in children.

4.3 Contraindications

Predisposition to bronchospasm.
β-adrenergic blockade of the smooth muscle of bronchi and bronchioles may result in an increased airways resistance. These drugs also reduce the effectiveness of asthma treatment. This may be dangerous in susceptible patients.
Therefore, β-blockers are contraindicated in any patient with a history of airways obstruction or a tendency to bronchospasm. Use of cardioselective β-blockers can also result in severe bronchospasm. If such therapy must be used, great caution should be exercised. Alternative therapy should be considered.
Allergic disorders (including allergic rhinitis) which may suggest a predisposition to bronchospasm.
Right ventricular failure secondary to pulmonary hypertension.
Significant right ventricular hypertrophy.
Second and third degree atrioventricular block.
Shock (including cardiogenic and hypovolaemic shock).
Unstable decompensated congestive heart failure (pulmonary oedema, hypoperfusion or hypotension).
Continuous or intermittent inotropic therapy acting through β-receptor agonism.
Clinically relevant sinus bradycardia (less than 45-50 beats/minute).
Noncompensated congestive heart failure (see Section 4.4 Special Warnings and Precautions for Use).
Sick sinus syndrome (unless a permanent appropriately functioning pacemaker is in place).
Severe peripheral arterial circulatory disorders.
Suspected acute myocardial infarction with a heart rate of < 45 beats/minute, a P-R interval of > 0.24 seconds or a systolic blood pressure of < 100 mmHg, and/or moderate to severe noncompensated heart failure.
Hypotension.
Untreated phaeochromocytoma (see Section 4.4 Special Warnings and Precautions for Use).
Hypersensitivity to any component of Minax XL and related derivatives. Cross sensitivity between β-blockers can occur.

4.4 Special Warnings and Precautions for Use

Symptomatic cardiac failure.

β-blockers should not be used in patients with unstabilised heart failure. This condition should first be stabilised with appropriate treatment (e.g. angiotensin converting enzyme inhibitors, digoxin, diuretics). If cardiac failure persists, Minax XL should be discontinued gradually (see Section 4.4 Special Warnings and Precautions for Use, Abrupt withdrawal).

Bronchospasm.

Where Minax XL is prescribed for patients known to be suffering from asthma, an inhaled β2-agonist should be administered. The dosage of β2-agonists may require adjustment (increase), however the risk of modified release metoprolol succinate interfering with β2-receptors is less than with conventional tablet formulations of β1-selective blockers.

Concomitant therapy with calcium antagonists.

The concomitant use of calcium antagonists with myocardial suppressant and sinus node activity (e.g. verapamil and to a lesser extent diltiazem) and β-blockers may cause bradycardia, hypotension and asystole. Extreme caution is required if these drugs have to be used together (see Section 4.5 Interactions with Other Medicines and Other Forms of Interactions).

Anti-arrhythmic drugs.

Care should be taken when prescribing β-blockers with antiarrhythmic drugs as they may enhance the negative inotropic and chronotropic effects (see Section 4.5 Interactions with Other Medicines and Other Forms of Interactions).

Diabetes.

Minax XL should be used with caution in patients with diabetes mellitus, especially those who are receiving insulin or oral hypoglycaemic agents. Diabetic patients should be warned that β-blockers affect glucose metabolism and may mask some important premonitory signs of acute hypoglycaemia, such as tachycardia.
In patients with insulin or noninsulin dependent diabetes, especially labile diabetes, or with a history of spontaneous hypoglycaemia, β-blockade may result in the loss of diabetic control and delayed recovery from hypoglycaemia. The dose of insulin or oral hypoglycaemic agent may need to be adjusted. Diabetic patients receiving Minax XL should be monitored to ensure diabetes control is maintained.

Other metabolic effects.

Beta-adrenoreceptors are involved in the regulation of lipid as well as carbohydrate metabolism. Some drugs affect the lipid profile adversely although the long-term clinical significance of this change is unknown and the effect appears to be less for drugs with intrinsic sympathomimetic activity.

Conduction disorders.

Very rarely a pre-existing A-V conduction disorder of moderate degree may become aggravated (possibly leading to A-V block). Minax XL should be administered with caution to patients with first degree A-V block (see Section 4.3 Contraindications).

Peripheral vascular disease.

β-blockade may impair the peripheral circulation and exacerbate the symptoms of peripheral vascular disease (see Section 4.3 Contraindications).

Bradycardia.

If patients develop increasing bradycardia, Minax XL should be given in lower doses or gradually withdrawn.

Prinzmetal angina.

There is a risk of exacerbating coronary artery spasm if patients with Prinzmetal or variant angina are treated with a β-blocker. If this treatment is essential, it should only be undertaken in a coronary or intensive care unit.

Effects on the thyroid.

The effects of β-blockers on thyroid hormone metabolism may result in elevations of serum free thyroxine (T4) levels. In the absence of any signs or symptoms of hyperthyroidism, additional investigation is necessary before a diagnosis of thyrotoxicosis can be made.

Phaeochromocytoma.

Where Minax XL is prescribed for a patient known to be suffering from phaeochromocytoma, an α-blocker should be given concomitantly to avoid exacerbation of hypertension.

Effects on the eye and skin.

Various skin rashes and conjunctival xerosis have been reported with β-blocking agents. Cross reactions may occur between β-blockers, therefore substitutions within the group may not necessarily preclude occurrence of symptoms.
During long-term treatment with the β-blocking drug practolol a specific rash bearing a superficial resemblance to psoriasis was occasionally described. In a number of the patients affected, this rash was accompanied by adverse effects on the eye (xerophthalmia and/or keratoconjunctivitis) of varying severity. This condition is called the oculomucocutaneous or practolol syndrome. On a few rare occasions, serious otitis media, sclerosing peritonitis and pleurisy have been reported as part of this syndrome.
The oculomucocutaneous syndrome as reported with practolol has not been reported with metoprolol. However, dry eyes and skin rash have been reported with metoprolol. If such symptoms occur, discontinuation of metoprolol should be considered.
Recently, an association between Peyronie's disease (a fibrosing induration of the penis) and various β-blockers has been suggested but is not proven.

General anaesthesia.

Prior to surgery the anaesthetist should be informed that the patient is receiving Minax XL because of the potential for interactions with other drugs, resulting in severe bradyarrhythmias and hypotension, decreased reflex ability to compensate for blood loss, hypovolaemia and regional sympathetic blockade, and decreased propensity for vagal induced bradycardia (see Section 4.5 Interactions with Other Medicines and Other Forms of Interactions). It is not recommended to stop β-blocker treatment in patients undergoing surgery. Acute initiation of high dose metoprolol to patients undergoing noncardiac surgery should be avoided, since it has been associated with bradycardia, hypotension and stroke including fatal outcome in patients with cardiovascular risk factors.
If it is thought necessary to withdraw β-blocker therapy before surgery, this should be done gradually and completed about 48 hours before surgery (see Section 4.4 Special Warnings and Precautions for Use, Abrupt withdrawal).

Abrupt withdrawal.

Abrupt withdrawal of β-blockade is hazardous, especially in high risk patients, and should not be done. If there is a need to discontinue treatment with Minax XL, this should be done gradually over at least two weeks with the dose reduced by half in each step, down to a final dose of half a 23.75 mg tablet. The final dose should be taken for at least four days before discontinuation. Close observation of the patient is required during the withdrawal phase. If symptoms occur, a slower withdrawal rate is recommended. Sudden withdrawal of β-blockade may aggravate chronic heart failure and also increase the risk of myocardial infarction and sudden death.

Allergic conditions.

Allergic reactions may be exaggerated by β-blockade (e.g. allergic rhinitis during the pollen season and allergic reactions to bee and wasp stings). β-blockers should be avoided if there is a risk of bronchospasm.
In patients taking β-blockers, anaphylactic shock assumes a more severe form and may be resistant to usual doses of adrenaline (epinephrine). Whenever possible, β-blockers should be avoided in patients who are at increased risk of anaphylaxis.

Hyperthyroidism.

Because β-blockers may mask the clinical signs of developing or continuing hyperthyroidism resulting in symptomatic improvement without any change in thyroid status, special care should be exercised in hyperthyroid patients who are also receiving β-blockers. Where Minax XL is administered to patients having, or suspected of developing thyrotoxicosis, both thyroid and cardiac function should be closely monitored.

Effects on the heart rate.

If the patient develops increasing bradycardia (heart rate less than 50 to 55 beats/minute), the dosage of Minax XL should be gradually reduced or treatment gradually withdrawn (see Section 4.3 Contraindications).

Use in hepatic impairment.

Metoprolol is mainly eliminated by hepatic metabolism (see Section 5.2 Pharmacokinetic Properties). Therefore, liver cirrhosis may increase the systemic bioavailability of metoprolol and reduce its total clearance, leading to increased plasma levels.

Use in renal impairment.

In patients with severe renal disease haemodynamic changes following β-blockade may impair renal function further. β-blockers which are excreted mainly by the kidney may require dose adjustment in patients with renal failure.

Use in the elderly.

See Section 4.2 Dose and Method of Administration; Section 5.2 Pharmacokinetic Properties.

Paediatric use.

The safety and efficacy of metoprolol in children has not been established.

Effects on laboratory tests.

No data available.

4.5 Interactions with Other Medicines and Other Forms of Interactions

CYP2D6 inhibitors.

Coadministration of drugs which inhibit CYP2D6 such as quinidine, fluoxetine and paroxetine may cause increased exposure to metoprolol and consequent increased pharmacological effects.
Concomitant administration of the CYP2D6 inhibitor quinidine has been shown to substantially increase systemic exposure of both enantiomers of metoprolol. In healthy subjects with CYP2D6 extensive metaboliser phenotype, coadministration of quinidine 100 mg and immediate release metoprolol 200 mg tripled the concentration of S-metoprolol and doubled the metoprolol elimination half-life. These increases in plasma concentration are highly likely to be associated with exaggerated pharmacological effects and decrease in the cardioselectivity of metoprolol. Interactions with hydroxychloroquine and diphenhydramine, although smaller, could still be clinically significant.

Other antihypertensive agents.

Metoprolol enhances the effects of other antihypertensive drugs. Particular care is required when initiating administration of a β-blocker and prazosin together.

Sympathetic ganglion blocking agents, other β-blockers or monoamine oxidase (MAO) inhibitors.

Patients receiving concomitant treatment with sympathetic ganglion blocking agents, other β-blockers (including eye drops), or monoamine oxidase (MAO) inhibitors should be kept under close surveillance.

Clonidine.

Concurrent use of β-blockers and clonidine should be avoided because of the risk of adverse interaction and severe withdrawal symptoms.
If concomitant treatment with clonidine is to be discontinued, the β-blocker medication should be withdrawn several days before the gradual withdrawal of clonidine. The rebound hypertension associated with clonidine withdrawal can be exacerbated by the presence of a β-blocker. If both drugs are withdrawn simultaneously, a marked rise in blood pressure and/or arrhythmias may result.
If replacing clonidine by β-blocker therapy, the introduction of β-blockers should be delayed for several days after clonidine administration has stopped.

Calcium antagonists.

If Minax XL is given with calcium antagonists of the verapamil and diltiazem type the patient should be monitored for possible negative inotropic and chronotropic effects. Calcium antagonists of the phenylalkylamine type (e.g. verapamil) should not be given by intravenous administration to patients treated with metoprolol because there is a risk of cardiac arrest in this situation. Patients taking oral calcium antagonists of this type in combination with metoprolol should be closely monitored.
The combination of β-blockers with dihydropyridine calcium channel blockers with a weak myocardial depressant effect (e.g. felodipine, nifedipine) can be administered together with caution. In case excess hypotension develops, the calcium antagonist should be stopped or the dosage reduced.

Antiarrhythmic agents.

When metoprolol is given together with antiarrhythmic agents, the patients should be monitored for possible negative inotropic and chronotropic effects. The negative inotropic and negative chronotropic effects of antiarrhythmic agents of the quinidine type and amiodarone may be enhanced by β-blockers. Interactions have been reported during concomitant β-blocker therapy with the class IA agents disopyramide, and less frequently quinidine; class IB agents, tocainide, mexiletine and lidocaine (lignocaine); the class IC agent flecainide; the class III agent amiodarone; and the class IV antiarrhythmic agents (e.g. verapamil).

Anaesthetics.

In patients receiving β-blocker therapy, inhalation anaesthetics enhance the cardiodepressant effect (see Section 4.4 Special Warnings and Precautions for Use). Metoprolol may also reduce the clearance of other drugs (e.g. lidocaine (lignocaine)).
Modern inhalational anaesthetic agents are generally well tolerated, although older agents (ether, cyclopropane, methoxyflurane, trichlorethylene) were sometimes associated with severe circulatory depression in the presence of β-blockage.

Liver enzyme effects.

Enzyme inducing and enzyme inhibiting substances may exert an influence on the plasma level of metoprolol. The plasma concentration of metoprolol is lowered by rifampicin and may be raised by cimetidine, alcohol, hydralazine, and selective serotonin reuptake inhibitors (SSRIs) e.g. paroxetine, fluoxetine, and sertraline, quinidine, verapamil and diphenhydramine.

Prostaglandin synthetase inhibiting agents.

Concomitant treatment with indometacin or other prostaglandin synthetase inhibiting agents may decrease the antihypertensive effect of β-blockers.

Alcohol.

Metoprolol may modify the pharmacokinetic behaviour of alcohol when taken together. The plasma level of metoprolol may be raised by alcohol.

Oral antidiabetic agents.

The dosages of oral antidiabetics may need to be adjusted in patients receiving β-blockers (see Section 4.4 Special Warnings and Precautions for Use).

Warfarin.

A limited number of reports have demonstrated a rise in AUC and concentration of warfarin when taken with another β-blocker. This could potentially increase the anticoagulant effect of warfarin.

Catecholamine depleting agents.

Concomitant use of catecholamine depleting drugs such as reserpine, monoamine oxidase (MAO) inhibitors and guanethidine have an additive effect when given with β-blocking agents. Patients treated with Minax XL plus a catecholamine depletor should therefore be closely observed for evidence of hypotension or marked bradycardia, which may produce vertigo, syncope, or postural hypotension, since the added effect of a β-blocker may produce an excessive reduction of the resting sympathetic nervous tone.

Digitalis glycosides.

Digitalis glycosides, in association with β-blockers, may increase atrioventricular conduction time and may induce bradycardia.

4.6 Fertility, Pregnancy and Lactation

Effects on fertility.

In rats dosed with 500 mg/kg/day (23 times the MRCD on a mg/m2 basis), there was a slight decrease in insemination rate (75% cf. 95% in untreated controls) with signs of maternal toxicity. There was no evidence of impaired fertility at 50 mg/kg/day (2.3 times the MRCD).
(Category C)
As with most drugs, Minax XL should not be given during pregnancy unless its use is considered essential. As with all antihypertensive agents, β-blockers may cause side effects (e.g. reduced placental perfusion and bradycardia) in the foetus and newborn. Reduced placental perfusion has been associated with growth retardation, intrauterine death, abortion and early labour. It is therefore suggested that appropriate maternofoetal monitoring be performed in pregnant women treated with Minax XL. During the late stages of pregnancy these drugs should only be given after weighing the needs of the mother against the risk to the foetus.
The lowest possible dose should be used and discontinuation of treatment should be considered at least 2 to 3 days before delivery to avoid increased uterine contractility and effects of β-blockade in the newborn (e.g. bradycardia, hypoglycaemia).
Metoprolol tartrate was shown to increase foetal loss in rabbits at 25 mg/kg/day PO (2 times the MRCD on a mg/m2 basis), and increase still births and decrease neonatal survival in rats at 500 mg/kg/day PO (23 times the MRCD on a mg/m2 basis). These studies revealed no evidence of teratogenicity.
As with most drugs, Minax XL should not be given during lactation unless its use is considered essential. As with all antihypertensive agents, β-blockers may cause side effects (e.g. bradycardia) in the breastfed infant. The amount of metoprolol ingested via breast milk seems to be negligible, in regard to β-blocking effect in the infant, if the mother is treated with metoprolol in doses within the normal therapeutic range.
Postnatal growth was not affected in lactating rats dosed with metoprolol tartrate at up to 500 mg/kg/day PO (23 times the MRCD on a mg/m2 basis).

4.7 Effects on Ability to Drive and Use Machines

Minax XL may occasionally cause dizziness, visual disturbances or fatigue (see Section 4.8 Adverse Effects (Undesirable Effects)), hence patients should know how they react to Minax XL before they drive or use machinery, particularly when starting or changing treatment.

4.8 Adverse Effects (Undesirable Effects)

Minax XL is well tolerated and adverse reactions have generally been mild and reversible. The following events have been reported as adverse events in clinical trials or reported from routine use, mostly with conventional metoprolol (metoprolol tartrate). In many cases a relationship with metoprolol has not been established.
The following definitions of frequency are used: very common ≥ 10%; common 1-9.9%; uncommon 0.1-0.9%; rare 0.01-0.09%; very rare < 0.01%.

Cardiovascular.

Common: bradycardia, postural disorders (very rarely with syncope), cold hands and feet (Raynaud's phenomenon), palpitations.
Uncommon: transient deterioration of heart failure symptoms, A-V block I, oedema, precordial pain, cardiogenic shock in patients with acute myocardial infarction*.
Rare: disturbances of cardiac conduction, cardiac arrhythmias.
Very rare: gangrene in patients with pre-existing severe peripheral circulatory disorders.
*Excess frequency of 0.4% compared with placebo in a study of 46000 patients with acute myocardial infarction where the frequency of cardiogenic shock was 2.3% in the metoprolol group and 1.9% in the placebo group in the subset of patients with low shock risk index. The shock risk index was based on the absolute risk of shock in each individual patient derived from age, sex, time delay, Killip class, blood pressure, heart rate, ECG abnormality, and prior history of hypertension. The patient group with low shock risk index corresponds to the patients in which metoprolol is recommended for use in acute myocardial infarction.

Central nervous system.

Very common: fatigue.
Common: dizziness, headache.
Uncommon: paraesthesia, muscle cramps.

Gastrointestinal.

Common: nausea, diarrhoea, constipation, abdominal pain.
Uncommon: vomiting.
Rare: dry mouth.

Haematologic.

Very rare: thrombocytopenia.

Hepatic.

Rare: liver function test abnormalities.
Very rare: hepatitis.

Metabolic.

Uncommon: weight gain.

Psychiatric.

Uncommon: depression, impaired concentration, somnolence or insomnia, nightmares.
Rare: nervousness, anxiety, impotence/sexual dysfunction.
Very rare: amnesia/memory impairment, confusion, hallucinations.

Respiratory.

Common: dyspnoea on exertion.
Uncommon: bronchospasm (which may also occur in patients without a history of obstructive lung disease).
Rare: rhinitis.

Sense organs.

Rare: disturbances of vision, dry and/or irritated eyes, conjunctivitis.
Very rare: tinnitus, taste disturbances.

Skin.

Uncommon: rash (in the form of urticaria, psoriasiform and dystrophic skin lesions), increased sweating.
Rare: loss of hair.
Very rare: photosensitivity reactions, aggravated psoriasis.

Miscellaneous.

Very rare: arthralgia.

Reporting suspected adverse effects.

Reporting suspected adverse reactions after registration of the medicinal product is important. It allows continued monitoring of the benefit-risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions at www.tga.gov.au/reporting-problems.

4.9 Overdose

Symptoms.

Symptoms of overdosage may include severe hypotension, cardiac insufficiency, bradycardia and bradyarrhythmia, cardiac conduction disturbances, cardiogenic shock, cardiac arrest, impairment of consciousness/coma, convulsions and bronchospasm. The main clinical signs of overdosage are cardiovascular and in some cases decompensation may be rapid. Overdosage with Minax XL can lead to death.
Cases of overdosage in paediatric patients need to be given extra attention even if the patient appears well on presentation and even if only a small number of tablets have apparently been taken.

Management.

Care should be provided at a facility that can provide appropriate supporting measures, monitoring, and supervision.
Activated charcoal may reduce absorption of the medicine if given within one or two hours after ingestion. In patients who are not fully conscious or have impaired gag reflex, consideration should be given to administering activated charcoal via a nasogastric tube, once the airway is protected.
Syrup of ipecac and gastric lavage are no longer considered to be standard therapy for gut decontamination.
Atropine, adrenostimulating drugs or pacemaker to treat bradycardia and conduction disorders.
Hypotension, acute cardiac failure, and shock to be treated with suitable volume expansion, injection of glucagon (if necessary, followed by an intravenous infusion of glucagon), intravenous administration of adrenostimulating drugs such as dobutamine, with α1-receptor agonistic drugs added in presence of vasodilation. Intravenous use of calcium salts (Ca2+) can also be considered.
Bronchospasm can usually be reversed by bronchodilators.
For information on the management of overdose, contact the Poisons Information Centre on 13 11 26 (Australia).

5 Pharmacological Properties

5.1 Pharmacodynamic Properties

Mechanism of action.

Metoprolol is a β1-selective β-blocker, i.e. it blocks β1-receptors at doses lower than those needed to block β2-receptors.
Metoprolol is practically devoid of membrane stabilising activity and does not display partial agonist activity (i.e. intrinsic sympathomimetic activity = ISA) at doses required to produce β-blockade. The stimulant effect of catecholamines on the heart is reduced or inhibited by metoprolol. This leads to a decrease in heart rate, cardiac output, cardiac contractility and blood pressure.
Modified release metoprolol succinate and the immediate release metoprolol tartrate are not bioequivalent. Modified release metoprolol succinate gives an even plasma concentration time profile and effect (β1-blockade) over 24 hours in contrast to conventional tablet formulations of β1-selective blockers including metoprolol tartrate formulations.
When given together with a β2-agonist, metoprolol succinate in therapeutic doses interferes less than nonselective β-blockers with β2-mediated bronchodilation (see Section 4.4 Special Warnings and Precautions for Use). When clinically necessary, metoprolol succinate, in combination with a β2-agonist, may be given to patients with symptoms of obstructive pulmonary disease. Metoprolol succinate also interferes less with insulin release than nonselective β-blockers.

Clinical trials.

Three randomised, double blind, placebo controlled studies and one randomised, open crossover study had been conducted to establish the efficacy and safety of modified release metoprolol succinate in patients with chronic heart failure.
The pivotal study, MERIT-HF (n = 3991), was a survival study in patients with NYHA (New York Heart Association) functional class II-IV and decreased ejection fraction (≤ 0.40) on optimal standard therapy at enrolment. Patients were randomised to receive either modified release metoprolol succinate (n = 1990) or placebo (n = 2001) once daily. The dose of modified release metoprolol succinate was titrated during 6-8 weeks to the target of 200 mg. Treatment ranged from 0 to 622 days with a mean duration of one year.
Participants were predominantly male (76%), Caucasian (94%), previous (55%) or current (19%) smokers, aged 60-79 years (66%; mean age 64), with heart failure secondary to ischaemia (65%). Most had mild to moderate symptomatic heart failure at baseline: 41% in NYHA class II, 56% in class III and 4% in class IV. The mean ejection fraction was 0.28. About half the patients had a history of hypertension (44%) and/or myocardial infarction (48%). 25% had a history of diabetes mellitus. 10-20% had peripheral oedema, jugular venous distension, pulmonary rales and/or hepatomegaly. 23% had a third heart sound, 34% had a heart murmur, 25% had an irregular heart beat and 16% were in atrial fibrillation. 90% of patients were on one or more diuretics, 89% on an angiotensin converting enzyme inhibitor, 7% on an angiotensin II blocker, 63% on digitalis, 36% on long acting nitrates, 54% on aspirin, 37% on an oral anticoagulant and 23% on a statin.
Table 2 summarises the results of the efficacy variables for modified release metoprolol succinate compared to placebo.
The numbers needed to treat (NNT) to achieve a reduction of 1 case of all cause mortality, cardiac death and nonfatal AMI, mortality from cardiovascular causes and from sudden death are as follows (see Table 3).
Modified release metoprolol succinate was generally well tolerated. Treatment was ceased due to adverse events in 10.3% of patients taking modified release metoprolol succinate compared to 12.3% of those taking placebo. Compared to placebo, the overall rate of treatment withdrawal and withdrawal due to worsening heart failure tended to be less with modified release metoprolol succinate, but the difference did not reach statistical significance.

5.2 Pharmacokinetic Properties

Absorption.

After rapid disintegration within the gastrointestinal tract, metoprolol is continuously released for approximately 20 hours, and a stable metoprolol plasma concentration is achieved over a dosage interval of 24 hours.

Distribution.

Approximately 12% of metoprolol is bound to human serum proteins.

Metabolism.

Metoprolol undergoes oxidative metabolism in the liver, primarily by CYP2D6. Due to polymorphism of CYP2D6, about 5-10% of Caucasians and a lower percentage of Asian and African populations are poor metabolisers of metoprolol. Such people experience higher plasma concentrations of metoprolol for a given dose. Because of these differences between individuals, gradual dose titration is important. Coadministration of drugs which inhibit CYP2D6 may increase plasma concentrations of metoprolol, particularly in extensive metabolisers (the majority of the population). Three main metabolites have been identified, although none have a beta-blocking effect of clinical importance.

Excretion.

Over 95% of an oral dose can be recovered in the urine. Only approximately 5% of the administered dose is excreted unchanged, with this figure rising to 30% in isolated cases.

Pharmacokinetics in the elderly.

The elderly shows no significant differences in the pharmacokinetics of metoprolol as compared with younger persons.

5.3 Preclinical Safety Data

Genotoxicity.

Metoprolol tartrate was not mutagenic in a bacterial assay, nor did it induce chromosomal damage in Chinese hamsters (bone marrow micronucleus and chromosome aberration assays) or in mice (dominant lethal assay).

Carcinogenicity.

Long-term studies in animals have been conducted to evaluate the carcinogenic potential of metoprolol tartrate. In rats at dietary doses of up to 800 mg/kg/day (36 times the maximum recommended clinical dose (MRCD) on a mg/m2 basis) for 18 months, there was no increase in the incidence of neoplasms. The only histologic changes that appeared to be drug related were an increased incidence of focal accumulation of foamy macrophages in pulmonary alveoli and an increased incidence of biliary hyperplasia.
In a 21 month study in CD-1 mice at dietary doses of up to 750 mg/kg/day (17 times the MRCD on a mg/m2 basis), benign lung tumours (small adenomas) occurred more frequently in female mice receiving the highest dose than in untreated control animals. There was no increase in malignant or total (benign plus malignant) lung tumours, nor in the overall incidence of tumours.

6 Pharmaceutical Particulars

6.1 List of Excipients

Microcrystalline cellulose, ethylcellulose, macrogol 400, hypromellose, colloidal anhydrous silica, macrogol 6000, sodium stearylfumarate, Opadry II complete film coating system 32K58990 White (ARTG PI No: 108533).

6.2 Incompatibilities

Incompatibilities were either not assessed or not identified as part of the registration of this medicine.

6.3 Shelf Life

In Australia, information on the shelf life can be found on the public summary of the Australian Register of Therapeutic Goods (ARTG). The expiry date can be found on the packaging.

6.4 Special Precautions for Storage

Store below 25°C.

6.5 Nature and Contents of Container

Container type (all strengths): PA/Al/PVC/Al or PVC/PCTFE (Aclar)/Al.

Minax XL 23.75 tablets (23.75 mg).

Available in blister packs of 15 and 30 tablets.

Minax XL 47.5 tablets (47.5 mg).

Available in blister packs of 30 tablets.

Minax XL 95 tablets (95 mg).

Available in blister packs of 30 tablets.

Minax XL 190 tablets (190 mg).

Available in blister packs of 30 tablets.
Some strengths, pack sizes and/or pack types may not be marketed.

Australian register of therapeutic goods (ARTG).

AUST R 205151 - Minax XL metoprolol succinate 23.75 mg modified release tablet blister pack.
AUST R 205149 - Minax XL metoprolol succinate 47.5 mg modified release tablet blister pack.
AUST R 205148 - Minax XL metoprolol succinate 95 mg modified release tablet blister pack.
AUST R 205150 - Minax XL metoprolol succinate 190 mg modified release tablet blister pack.

6.6 Special Precautions for Disposal

In Australia, any unused medicine or waste material should be disposed of by taking it to your local pharmacy.

6.7 Physicochemical Properties

Metoprolol succinate is a white, crystalline powder with a melting point of approximately 138°C. It is freely soluble in water, soluble in methanol, slightly soluble in alcohol, and very slightly soluble in ethyl acetate.

Chemical structure.

Chemical name: Bis[(2RS)-1-[4-(2-methoxyethyl)phenoxy]-3-[(1-methylethyl)amino] propan-2-ol] butanedioate.
Structural formula:
Molecular formula: C34H56N2O10. Molecular weight: 653.

CAS number.

98418-47-4.

7 Medicine Schedule (Poisons Standard)

S4 (Prescription Only Medicine).

Summary Table of Changes