Consumer medicine information

Sorbidin Tablets

Isosorbide dinitrate

BRAND INFORMATION

Brand name

Sorbidin Tablets

Active ingredient

Isosorbide dinitrate

Schedule

S3

 

Consumer medicine information (CMI) leaflet

Please read this leaflet carefully before you start using Sorbidin Tablets.

What is in this leaflet

This leaflet answers some common questions about Sorbidin.

It does not contain all of 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 Sorbidin against the benefits they expect it will have 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 Sorbidin is used for

Sorbidin is used to prevent angina. It is not for the relief of a sudden attack of angina.

Angina is a pain or uncomfortable feeling in the chest, often spreading to the arms or neck, and sometimes to the shoulders and back. This may be caused by too little blood and oxygen getting to the heart. The pain of angina is usually brought on by exercise or stress.

Sorbidin may also be used in the management of some types of heart failure.

Sorbidin belongs to a group of medicines called nitrates. These medicines work by widening blood vessels and thus allowing more blood and oxygen to reach the heart.

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

Sorbidin is not recommended for use in children, as there have been no studies of its effects in children.

Before you take Sorbidin

When you must not take it

Do not take Sorbidin if you are allergic to medicines containing isosorbide dinitrate, any other nitrate or nitrite drug, or any of the ingredients listed at the end of this leaflet.

Some of the symptoms of an allergic reaction may include skin rash, itching or hives, swelling of the face, lips or tongue which may cause difficulty in swallowing or breathing, wheezing or shortness of breath.

Do not take Sorbidin if you have:

  • recently had a heart attack
  • extremely low blood pressure
  • certain other heart conditions
  • increased pressure in the head from any cause, including stroke, tumour, head injury
  • severe anaemia (lack of red blood cells).

Do not take Sorbidin if you are taking sildenafil (Viagra), a medicine used to treat impotence in men.

Taking these two medicines together may cause your blood pressure to drop to a dangerously low level.

Do not take Sorbidin to relieve a sudden attack of angina.

Sorbidin is only for the prevention of angina.

Do not take Sorbidin if you are pregnant or breastfeeding.

Your doctor will discuss with you the risks and benefits involved.

Do not take Sorbidin if the expiry date (Exp.) printed on the pack has passed.

Do not take Sorbidin if the packaging shows signs of tampering or the tablets do not look quite right.

Before you start to take it

Tell your doctor if you are allergic to any other medicines, foods, dyes or preservatives.

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

  • recent heart attack or stroke
  • low blood pressure
  • blood disorders such as anaemia
  • blood vessel disorders such as hardening of the arteries
  • glucose-6-phosphate dehydrogenase deficiency
  • liver problems
  • kidney problems.

Your doctor may want to take special care if you have any of these conditions.

If you have not told your doctor about any of the above, tell them before you start taking Sorbidin.

Taking other medicines

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

Some medicines may be affected by Sorbidin, or may affect how well it works. These include:

  • medicines used to treat high blood pressure and other heart conditions
  • phenothiazines, a group of medicines used to treat some mental conditions
  • tricyclic antidepressants, a group of medicines used to treat depression
  • medicines used to relieve stomach cramps and to prevent travel sickness
  • non-steroidal anti-inflammatory agents (NSAIDs), medicines used to relieve pain, swelling and other symptoms of inflammation, including arthritis
  • sildenafil (Viagra).

Your doctor can tell you what to do if you are taking any of these medicines.

If you are not sure whether you are taking any of these medicines, check with your doctor or pharmacist.

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

How to take Sorbidin

How much to take

The dose varies from patient to patient.

Elderly patients may need smaller doses.

Angina: The usual dose is 10 mg (one tablet) four times a day.

Your doctor may advise you to take a different dose. This depends on your condition and whether or not you are taking any other medicines.

Heart Failure: Your doctor will tell you how many tablets you need to take each day and when to take them.

Follow all directions given to you by your doctor and pharmacist carefully.

How to take Sorbidin

Swallow the tablets with a glass of water.

When to take Sorbidin

Take Sorbidin on a regular basis to help reduce the number of angina attacks.

Sorbidin should not be taken for immediate relief of an angina attack.

Have a 10 to 12-hour nitrate-free period once every 24 hours.

For example, take your last evening dose then wait 10 to 12 hours before taking your next dose in the morning. This nitrate-free period is important to prevent tolerance and may help Sorbidin to work better.

It is recommended to take Sorbidin before meals.

If you forget to take Sorbidin

If it is almost time for your next dose, skip the dose you missed and take your next dose when you are meant to.

Otherwise, take the missed dose as soon as you remember, and then go back to taking your tablets as you would normally.

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

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

If you have any questions about this, check with your doctor or pharmacist.

How long to take Sorbidin for

To properly control your angina, Sorbidin must be taken every day on a long-term basis. Try not to miss any doses and take Sorbidin even if you feel well.

Keep taking Sorbidin for as long as your doctor recommends.

If you do not follow your doctor's instructions, you may not get relief from your angina.

If you take too much Sorbidin (overdose)

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

You may need urgent medical attention.

If you take too much Sorbidin, you may feel dizzy, light-headed, have a headache and a very fast heart beat.

While you are taking Sorbidin

Things you must do

Tell your doctor if you continue to have angina attacks or if they become more frequent while you are using Sorbidin.

Before starting any new medicine, tell your doctor or pharmacist that you are taking Sorbidin.

Tell all the doctors, dentists and pharmacists who are treating you that you are taking Sorbidin.

If you become pregnant while taking Sorbidin, tell your doctor.

If you plan to have surgery, including dental surgery, tell your doctor or dentist that you are taking Sorbidin.

Visit your doctor regularly so they can check on your progress.

Things you must not do

Do not take Sorbidin to relieve an angina attack that has already started.

This medicine will not relieve a sudden attack of angina. Your doctor will have prescribed a spray or other tablets to use under the tongue when you get an angina attack.

Do not stop taking Sorbidin, or lower the dose, without checking with your doctor or pharmacist.

Stopping Sorbidin suddenly may cause you to have angina attacks more often. Your doctor will gradually reduce the amount of Sorbidin you are taking over a period of two weeks before stopping completely.

Do not let yourself run out of Sorbidin.

If you do run out, Sorbidin can be purchased from a pharmacy without a prescription.

Do not use Sorbidin to treat any other conditions unless your doctor tells you to.

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

Things to be careful of

Be careful driving or operating machinery until you know how Sorbidin affects you.

Sorbidin may cause dizziness or lightheadedness in some people. If any of these occur, do not drive, operate machinery or do anything else that could be dangerous.

Be careful getting up from a sitting or lying position.

Dizziness, light-headedness or fainting may occur, especially when you get up quickly. Getting up slowly may help. The problem usually goes away after a few days, but if it gets worse or continues, talk to your doctor.

Be careful when drinking alcohol while taking Sorbidin.

If you drink alcohol while using Sorbidin, your blood pressure may drop, making you feel dizzy or faint.

Side effects

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

Like all other medicines, Sorbidin may have unwanted side effects in some people. Sometimes they are serious, most of the time they are not. You may need medical treatment 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.

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

You may not experience any of them.

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

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

  • headache
  • dizziness, lightheadedness, feeling faint.

These are the more common yet mild side effects. These effects are usually temporary. Pain relievers such as paracetamol are recommended to relieve headaches.

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

  • flushing of the face
  • swelling of the ankles, feet or hands
  • skin rash, flaking of the skin
  • nausea or vomiting
  • signs of anaemia such as tiredness, being short of breath and looking pale
  • severe or persistent headache.

These are less common but may require medical attention.

Tell your doctor immediately or go to Accident and Emergency at the nearest hospital if you notice any of the following:

  • severe dizziness or fainting (low blood pressure)
  • a very slow or fast heart beat.

These reactions can be life-threatening and require immediate medical attention.

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

After taking Sorbidin

Storage

Keep Sorbidin 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.

Keep your tablets in the bottle until it is time to take them.

If you take the tablets out of the bottle they may not keep well.

Keep your tablets in a cool dry place where the temperature stays below 30°C.

Do not store Sorbidin or any other medicine in the bathroom or near a sink.

Do not leave Sorbidin in the car or on window sills.

Heat and dampness can destroy some medicines.

Disposal

If your doctor tells you to stop taking Sorbidin, or your tablets have passed their expiry date, ask your pharmacist what to do with any that are left over.

Product description

What it looks like

Sorbidin is a round white tablet marked IS/10 on one side and a on the other.

Each pack contains 100 tablets.

Ingredients

The active ingredient in Sorbidin is isosorbide dinitrate. Each Sorbidin tablet contains 10 mg of isosorbide dinitrate.

The tablets also contain:

  • starch - pregelatinised maize
  • lactose anhydrous
  • cellulose - microcrystalline
  • magnesium stearate.

The tablets are gluten free.

Manufacturer

Sorbidin is made in Australia by:
Alphapharm Pty Limited
(ABN 93 002 359 739)
Level 1, 30 The Bond
30-34 Hickson Road
Millers Point NSW 2000
Phone: (02) 9298 3999

Medical Information
Phone: 1800 028 365

Australian registration number:
Sorbidin - Aust R 46043

This leaflet was prepared on
19 October 2010.

BRAND INFORMATION

Brand name

Sorbidin Tablets

Active ingredient

Isosorbide dinitrate

Schedule

S3

 

Name of the medicine

Isosorbide dinitrate (sorbide nitrate).

Actions

Antianginal, vasodilator.

Pharmacology

Isosorbide dinitrate is an organic nitrate ester. It has a slower time to onset of action, but longer duration of action than glyceryl trinitrate. The longer duration of action is due, in part, to the drug having a longer elimination half-life than glyceryl trinitrate and to the fact that its mononitrated metabolites are pharmacologically active and have long elimination half-lives (see Pharmacokinetics).
Like other organic nitrate ester drugs, the principal action of isosorbide dinitrate is to relax vascular smooth muscle. Venodilation causes venous pooling which reduces venous return, left ventricular filling pressure and pulmonary artery and capillary pressures. Myocardial oxygen requirements are also reduced. Arteriolar dilation can result in a reduction in afterload. The clinical implication of these haemodynamic changes in patients with congestive heart failure can be an increase in cardiac output and a reduction in symptoms of pulmonary vascular congestion. Patients with angina pectoris attain relief through a reduction in myocardial oxygen requirements.
Nitrates may cause a redistribution of coronary blood flow to ischaemic areas by selectively dilating large coronary vessels or collateral vessels which may develop secondary to myocardial ischaemia.

Pharmacokinetics.

An oral availability of at least 20% means that the oral route is effective in providing significant amounts of isosorbide dinitrate for systemic pharmacological effects. After chronic oral dosing at six hourly intervals, plasma levels of isosorbide dinitrate are greater than after single doses of the drug. This is associated with a reduced clearance of isosorbide dinitrate after chronic dosing.
An apparent terminal half-life of 1.1 to 1.3 hours has been reported for single oral and sublingual doses, and intravenous doses of isosorbide dinitrate. However, on monitoring plasma isosorbide dinitrate concentrations for up to 24 hours after chronic doses at six hourly intervals, a biexponential decay profile was reported with the first phase having a half-life of 1.1 hours and a second phase having a half-life of 7.7 hours. The first and faster half-life probably represents elimination of isosorbide dinitrate, while the second and slower half-life represents either protracted oral absorption or a redistribution of isosorbide dinitrate back from the peripheral tissues to the systemic circulation. The apparent disappearance half-lives of the 2 and 5-mononitrate metabolites are about three hours and four to six hours respectively.
There are no differences in plasma levels of isosorbide dinitrate after single oral doses of the drug in normal subjects and renal failure patients; but because isosorbide dinitrate and its mononitrate metabolites accumulate with chronic dosing, significant accumulation of the drug and its metabolites may occur, particularly in patients with hepatic and/or renal failure.

Indications

Treatment of angina pectoris (classic effort associated angina, chronic stable angina, vasospastic angina, variant angina, unstable angina and angina decubitus) and myocardial ischaemia due to ischaemic heart disease. The tablets are not intended to abort the acute anginal episode, but are useful in the prophylactic treatment of angina pectoris and myocardial ischaemia due to ischaemic heart disease.
An aid in the management of left ventricular failure, either alone or as part of the syndrome of congestive heart failure.

Contraindications

Patients with a confirmed diagnosis of isolated right ventricular failure, particularly in the setting of acute myocardial infarction and due to dominant right ventricular infarction.
Known hypersensitivity to isosorbide dinitrate, or a known idiosyncratic reaction to organic nitrate drugs.
Hypotension or uncorrected hypovolaemia, as the use of isosorbide dinitrate in such states could produce severe hypotension or shock.
Constrictive pericarditis and pericardial tamponade.
Severe anaemia or arterial hypoxaemia.
Intracranial hypertension.
Concurrent administration with sildenafil.

Warnings

As with other vasodilators, Sorbidin may cause paradoxical side effects in sensitive patients, which may increase ischaemia and may even lead to extension of myocardial damage and advanced congestive heart failure.

Acute myocardial infarction.

Data supporting the use of nitrates during the acute phase of myocardial infarction (the period during which clinical and laboratory findings are unstable) are insufficient to establish safety. Management of acute left ventricular failure secondary to acute myocardial infarction depends on accurate diagnosis, and may require flow directed cardiac catheterisation before institution of appropriate drug therapy.

Hypotension.

Care must be taken to avoid the significant risk of a precipitous fall in blood pressure, particularly in patients with severe coronary or cerebral atherosclerosis or renal insufficiency. Isosorbide dinitrate may cause faintness if taken while standing or sitting, and this hazard is of particular importance in patients not previously treated with the drug.

Withdrawal.

Nitrate dependence is a potentially serious problem. In terminating treatment of patients with angina who are receiving isosorbide dinitrate, both the dosage and frequency of administration should be gradually reduced over a period of two weeks to prevent potential withdrawal reactions such as increased frequency of angina attacks.

Tolerance.

During sustained therapy with isosorbide dinitrate, partial tolerance to the antianginal and circulatory effects may develop. Cross tolerance to other organic nitrates or nitrites may occur.

Precautions

In the treatment of acute or chronic cardiac failure, pulmonary capillary pressure should not be allowed to fall below 15 mmHg or systolic blood pressure below the physiological range in normal or hypertensive patients. Systolic pressure should be preserved in patients with pre-existing hypotension in the range of 90 to 100 mmHg.
Marked symptomatic, orthostatic hypotension has been reported when calcium channel blockers and organic nitrates were used in combination. Dose adjustment of either class of agents may be necessary.
Nitrate therapy may aggravate the angina caused by hypertrophic cardiomyopathy.
Tolerance to this drug and cross tolerance to other nitrates and nitrites may occur.

Hypoxaemia.

Arterial oxygen tension decreases after administration of glyceryl trinitrate in normal subjects and in patients with coronary artery disease, and therefore it is advised that isosorbide dinitrate should be used cautiously in hypoxic patients because a decrease in available oxygen may oppose the antianginal effect of isosorbide dinitrate.

Haemolytic anaemia.

Isosorbide dinitrate has been reported to induce haemolytic anaemia in glucose-6-phosphate dehydrogenase deficient patients.

Relief of acute episodes of angina.

Oral isosorbide dinitrate tablets should not be administered for rapid relief of the pain of angina.

Relief of left ventricular failure.

If left ventricular filling pressures are not elevated at the time isosorbide dinitrate is administered, the drug may cause severe hypotension due to a reduction in cardiac output.

Impaired hepatic function.

Isosorbide dinitrate is, in part, metabolised by the liver and therefore impairment of hepatic function may necessitate a reduction in dosage.

Impaired renal function.

In patients with renal failure, the plasma concentrations of isosorbide dinitrate and its active metabolites after single oral doses of the drug are not different from those seen in subjects with normal renal function. Although only 5% of a single dose of isosorbide dinitrate is excreted in the urine as the mononitrate metabolites, it is possible that with chronic dosing of isosorbide dinitrate, renal impairment could cause clinically significant accumulation of the active mononitrate metabolites (see Pharmacology, Pharmacokinetics).

Use in pregnancy.

(Category B1)
The safety of isosorbide dinitrate in pregnancy has not been established. The drug should not be administered to pregnant women unless, in the opinion of the doctor, the probable clinical benefits outweigh the possible hazards.

Use in lactation.

It is not known whether isosorbide dinitrate or its metabolites are excreted in milk, or whether it has a harmful effect on the newborn. Therefore, it is not recommended for breastfeeding mothers unless the expected benefits outweigh any potential risk.

Paediatric use.

As safety and efficacy have not been demonstrated for this age group, isosorbide dinitrate is not recommended for use in children.

Use in the elderly.

In general, the dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal or cardiac function, and of concomitant disease or other drug therapy.

Interactions

Patients receiving antihypertensive drugs or phenothiazines with nitrates should be observed for possible additive hypotensive effects.
Concomitant use with alcohol may cause hypotension due to enhanced vasodilatory effect of isosorbide dinitrate.
Caution should be observed when giving tricyclic antidepressants and anticholinergic agents concomitantly with isosorbide dinitrate, because these agents may potentiate the hypotensive effects of isosorbide dinitrate. Nonsteroidal anti-inflammatory drugs (NSAIDs) may attenuate the effects of isosorbide dinitrate, considering similar reports for glyceryl trinitrate.
The use of β-adrenergic blocking agents may require a reduction in isosorbide dinitrate dosage if excessive hypotension is to be avoided.
Concurrent administration of nitrates and sildenafil can potentiate the vasodilatory effects of nitrates, with the potential result of serious side effects such as syncope or myocardial infarction. Therefore, sildenafil should not be given to patients already receiving isosorbide dinitrate therapy.

Adverse Effects

Occasionally, individuals may exhibit marked sensitivity to the hypotensive effects of nitrates, even with the usual therapeutic dosage.

More common reactions.

Nervous system.

Headache, which may be temporary or persistent, is the most common adverse reaction in patients treated with isosorbide dinitrate; dizziness, especially postural.

Less common reactions.

Cardiovascular.

Cutaneous dilation with flushing; peripheral oedema.

Dermatological.

Rash, exfoliative dermatitis.

Gastrointestinal.

Nausea, vomiting.

Haematological.

Haemolytic anaemia in patients with glucose-6-phosphate dehydrogenase deficient syndrome (see Precautions).

Severe or life-threatening reactions.

Severe hypotension and bradycardia may be hazardous, particularly in patients with cerebral or coronary atherosclerosis. Reflex tachycardia may exacerbate ischaemic injury in patients with acute myocardial infarction.

Dosage and Administration

Tolerance to the anti-anginal effects (measured by exercise stress testing) and effects in heart failure of nitrates has been shown to be a major factor limiting efficacy and blunting the effect of sublingual nitroglycerin when nitrates are used either continuously (i.e. infusion, transdermal) or with any regular schedule of oral administration where dosing occurs every eight hours or more often during a day. The development of tolerance can be altered (prevented or attenuated) by a noncontinuous (intermittent or asymmetric) dosing schedule. In general, a nitrate free interval of at least 10 to 12 hours every 24 hours is recommended to prevent tolerance.

Angina pectoris and myocardial ischaemia due to ischaemic heart disease.

5 to 30 mg four times daily. The average patient requires 10 mg four times daily.

Left ventricular failure (either alone or as part of the syndrome of congestive heart failure).

In order to obtain full therapeutic effect, it is important that the dosage be individualised in accordance with each patient's needs, clinical response and haemodynamic monitoring. Sorbidin therapy should begin with the lowest effective dose and further adjusted as necessary, based on left ventricular performance. In the treatment of chronic left ventricular failure, the tablets may be used for maintenance therapy (20 to 40 mg four times daily or as needed).

Overdosage

Symptoms.

Overdosage of isosorbide dinitrate may result in severe hypotension and reflex tachycardia. Headache may be an indication of excessive overdosage.

Treatment.

Following recent ingestion of large numbers of isosorbide dinitrate tablets, gastric lavage and administration of oxygen with assisted respiration may be necessary. Hypotension and reflex tachycardia caused by overdosage can be treated by elevating the legs until the patient's condition stabilises. Since the duration of the haemodynamic effects following isosorbide dinitrate administration may be prolonged, additional corrective measures may be required. In that event, cautious administration of intravenous fluids or an α-adrenergic agonist (e.g. metaraminol) should be considered.

Presentation

Tablets, 10 mg (white, marked IS/10, α on reverse): 100's.

Storage

Store below 30°C.

Poison Schedule

S3.