Consumer medicine information

Blooms the Chemist Irbesartan

Irbesartan

BRAND INFORMATION

Brand name

Blooms the Chemist Irbesartan

Active ingredient

Irbesartan

Schedule

S4

 

Consumer medicine information (CMI) leaflet

Please read this leaflet carefully before you start using Blooms the Chemist Irbesartan.

What is in this leaflet

This leaflet answers some common questions about irbesartan. It does not contain all the available information. It does not take the place of talking to your doctor or pharmacist.

All medicines have risks and benefits. Your doctor has weighed the risks of you using this medicine against the benefits they expect it will have for you.

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

Keep this leaflet with the medicine. You may want to read it again.

What this medicine is used for

Irbesartan is used to treat high blood pressure and kidney disease in type 2 diabetic patients with high blood pressure. It belongs to a group of medicines known as angiotensin-II receptor antagonists.

How it works

Irbesartan relaxes your blood vessels, helping to lower your blood pressure. It also slows the decrease of kidney function in type 2 diabetic patients with high blood pressure.

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

This medicine is available only with a doctor's prescription.

This medicine is not addictive.

There is not enough information to recommend the use of this medicine in children.

Before you take this medicine

When you must not take it

Do not take this medicine if you have an allergy to:

  • irbesartan
  • any other angiotensin-II receptor antagonists or 'sartans'
  • any of the ingredients listed at the end of this leaflet

Some of the symptoms of an allergic reaction may include:

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

Do not take this medicine if you have or have had the following medical conditions:

  • diabetes or moderate to severe kidney impairment, and you are taking aliskiren
  • diabetic nephropathy and are on an ACE Inhibitor

Do not take this medicine if you are pregnant. Irbesartan may affect your developing baby if you take it during pregnancy.

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:

  • kidney problems, kidney transplant or dialysis
  • heart problems
  • liver problems
  • diabetes
  • high levels of potassium in your blood
  • recent excessive vomiting or diarrhoea
  • you are strictly restricting your salt intake
  • psoriasis

Tell your doctor if you are breastfeeding. Your doctor can discuss with you the risks and benefits involved.

Tell your doctor if you are planning to have surgery, dental treatment or an anaesthetic.

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

Taking other medicines

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

Some medicines may interact with irbesartan. These include:

  • other tablets for high blood pressure
  • fluid tablets or diuretics
  • lithium
  • potassium tablets, potassium containing salt substitutes or other medicines that may increase potassium
  • anti-inflammatory medicines (e.g. diclofenac, celecoxib)

Taking a combination of irbesartan with a thiazide diuretic (fluid tablet) and an anti-inflammatory medicine may damage your kidneys.

If you are taking any of these, you may need a different dose, or you may need to take different medicines.

Other medicines not listed above may also interact with irbesartan.

How to take this medicine

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

Your doctor will tell you how much of this medicine you should take, depending on your condition and whether you are taking any other medicines.

High blood pressure:
The usual starting dose is 150 mg daily. This can be increased to 300 mg daily on doctors’ advice.

Kidney disease caused by diabetes and high blood pressure:
The usual starting dose is 300 mg daily.

How to take it

Swallow the tablets whole with a glass of water.

When to take it

Take this medicine at about the same time each day. Taking it at the same time each day will have the best effect and will also help you remember when to take it.

It does not matter if you take it with or without food.

How long to take it

Continue taking your medicine for as long as your doctor tells you.

Make sure you have enough to last over weekends and holidays.

If you forget to take it

If it is almost time to take your next dose, skip the missed dose and take your next dose at the usual time.

Otherwise, take it as soon as you remember and then go back to taking your medicine as you would normally.

Do not take a double dose to make up for missed doses. This may increase the chance of you experiencing side effects.

If you have trouble remembering 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 your nearest hospital if you think that you or anyone else may have taken too much of this medicine. Do this even if there are no signs of discomfort or poisoning. You may need urgent medical attention.

While you are using this medicine

Things you must do

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

Tell any other doctors, dentists and pharmacists who are treating you that you take this medicine.

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

Tell your doctor if you are about to have any blood tests.

Tell your doctor if you are going to have surgery or an anaesthetic or are going into hospital.

Make sure you drink enough water during exercise and hot weather, especially if you sweat a lot.

Keep all of your doctor's appointments so that your progress can be checked. Your doctor may occasionally do tests to make sure the medicine is working and to prevent side effects.

Things you must not do

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

Do not take your medicine to treat any other complaint unless your doctor tells you to.

Do not stop taking your medicine or change the dosage without first checking with your doctor.

Things to be careful of

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

Side effects

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

This medicine helps most people with high blood pressure, but it may have unwanted side effects in a few people. 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.

Do not be alarmed by the following lists of 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:

  • headache
  • dizziness or light-headedness
  • unusual tiredness, weakness, fatigue
  • nausea or vomiting

The above list includes the more common side effects of your medicine.

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

  • skin rash or itchiness
  • muscle pain, aching muscles or joints not caused by exercise
  • buzzing, ringing or other persistent noise in the ears
  • yellowing of the skin and/or eyes
  • passing little urine, drowsiness, nausea, vomiting, breathlessness, loss of appetite, weakness (signs of kidney disease)
  • nausea, diarrhoea, muscle weakness and change in heart rhythm (signs of high potassium levels in the blood)

The above list includes serious side effects and you may need medical attention.

If any of the following occur, do not take any more of this medicine and tell your doctor immediately or go to Accident and Emergency at your nearest hospital:

  • shortness of breath, wheezing or difficulty breathing; swelling of the face, lips, tongue, throat or other parts of the body; rash, itching or hives on the skin (signs of an allergic reaction)

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

Tell your doctor or pharmacist if you notice anything that is making you feel unwell.

Other side effects not listed above may also occur in some people.

Storage and Disposal

Storage

Keep your medicine in its pack until it is time to take it. If you take your medicine out of its pack it may not keep well.

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

Do not store your medicine, 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 this medicine 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 left over.

Product description

What it looks like

White to off-white, oval shaped, biconvex, film-coated tablet.

75 mg tablets: Debossed with "L172" on one side and "75" on the other side. AUST R 259883.

150 mg tablets: Debossed with "L173" on one side and "150" on the other side. AUST R 259884.

300 mg tablets: Debossed with "L174" on one side and "300" on the other side. AUST R 259885.

Available in blister packs of 30 tablets.

* Not all strengths may be available.

Ingredients

Each tablet contains 75 mg, 150 mg or 300 mg of irbesartan as the active ingredient.

It also contains the following:

  • lactose
  • croscarmellose sodium
  • povidone
  • magnesium stearate
  • Opadry II complete film coating system 30F58652 white (ARPING 107860 consisting of hypromellose, macrogol 4000 and titanium dioxide).

This medicine does not contain gluten, sucrose, tartrazine or any other azo dyes.

Sponsor

Apotex Pty Ltd
16 Giffnock Avenue
Macquarie Park NSW 2113

This leaflet was prepared in February 2019.

Published by MIMS April 2019

BRAND INFORMATION

Brand name

Blooms the Chemist Irbesartan

Active ingredient

Irbesartan

Schedule

S4

 

1 Name of Medicine

Irbesartan.

6.7 Physicochemical Properties

Irbesartan is a white or almost white crystalline powder. Practically insoluble in water, sparingly soluble in methanol, slightly soluble in methylene chloride.
Irbesartan is a non-peptide angiotensin II receptor (AT1 subtype) antagonist.
Chemical name: 2-butyl-3-[(2'-(1H-tetrazol-5-yl) biphenyl-4-yl) methyl]-1,3-diazaspiro [4,4] non-1-en-4-one. Molecular formula: C25H28N6O. Molecular weight: 428.5.

Chemical structure.


CAS number.

138402-11-6.

2 Qualitative and Quantitative Composition

Each tablet contains 75 mg, 150 mg or 300 mg irbesartan as the active ingredient.

Excipients with known effect.

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

3 Pharmaceutical Form

75 mg tablets.

White to off-white, oval shaped, biconvex, film-coated tablet debossed with "L172" on one side and "75" on the other side.

150 mg tablets.

White to off-white, oval shaped, biconvex, film-coated tablet debossed with "L173" on one side and "150" on the other side.

300 mg tablets.

White to off-white, oval shaped, biconvex, film-coated tablet debossed with "L174" on one side and "300" on the other side.

5 Pharmacological Properties

5.1 Pharmacodynamic Properties

Mechanism of action.

Irbesartan is a specific antagonist of angiotensin II receptors (AT1 subtype). Angiotensin II is an important component of the renin-angiotensin system and is involved in the pathophysiology of hypertension and in sodium homeostasis. Irbesartan does not require metabolic activation for its activity.
Irbesartan blocks the potent vasoconstrictor and aldosterone-secreting effects of angiotensin II by selective antagonism of the angiotensin II (AT1 subtype) receptors localized on vascular smooth muscle cells and in the adrenal cortex. It has no agonist activity at the AT1 receptor and a much greater affinity (more than 8500-fold) for the AT1 receptor than for the AT2 receptor (a receptor that has not been shown to be associated with cardiovascular homeostasis).
Irbesartan does not inhibit enzymes involved in the renin-angiotensin system (i.e. renin, angiotensin converting enzyme [ACE]) or affect other hormone receptors or ion channels involved in the cardiovascular regulation of blood pressure and sodium homeostasis.
In healthy subjects, single oral irbesartan doses of up to 300 mg produced dose-dependent inhibition of the pressor effect of angiotensin II infusions. Inhibition was complete (≥ 90%) at the time of peak irbesartan concentrations and sustained for 24 hours (60% and 40% at 300 mg and 150 mg, respectively).
In hypertensive patients, angiotensin II receptor inhibition following chronic administration of irbesartan causes a 1.5-2 fold rise in angiotensin II plasma concentration and a 2-3 fold increase in plasma renin levels. Aldosterone plasma concentrations generally decline following irbesartan administration, however serum potassium levels are not significantly affected at recommended doses.
In hypertensive patients, chronic oral doses of irbesartan (up to 300 mg) had no effect on glomerular filtration rate, renal plasma/blood flow or filtration fraction. In multiple dose studies in hypertensive patients, there were no notable effects on fasting triglycerides, total cholesterol or HDL-cholesterol or fasting glucose concentrations. There was no effect on serum uric acid during chronic oral administration. Following repeated doses of irbesartan, there was no uricosuric effect.

Clinical trials.

The antihypertensive effects of irbesartan were examined in seven (7) major placebo-controlled 8-12 week trials in patients with baseline diastolic blood pressures of 95-110 mmHg.
The seven (7) studies of irbesartan monotherapy included a total of 1,915 patients randomised to irbesartan (1-900 mg) and 611 patients randomised to placebo. Once daily doses of 150 to 900 mg provided statistically and clinically significant decreases in systolic and diastolic blood pressure with a plateau in effect at doses above 300 mg.
Systolic/diastolic mean decreases in blood pressure at trough (24 hours post-dosing), compared to placebo, following 6 to 12 weeks of treatment were in the range of 7.5-9.9/4.6-6.2 mmHg with a 150 mg dose and 7.9-12.6/5.2-7.9 mmHg with a 300 mg dose.
Once-daily dosing with 150 mg gave trough and mean 24 hour responses corresponding to those observed in patients receiving twice-daily dosing at the same total daily dose. Peak (3-6 hour) effects were uniformly, but moderately, larger than trough effects, with the trough-to-peak ratio for systolic and diastolic response generally between 60-70%.
Two of the seven placebo-controlled trials identified above and two additional studies examined the antihypertensive effects of irbesartan and hydrochlorothiazide in combination.
Addition of a low dose of hydrochlorothiazide (12.5 mg) to irbesartan (75 to 300 mg) once daily resulted in further diastolic blood pressure reductions at trough (24 hours post-dosing) of 2.3-4.8 mmHg and an overall systolic/diastolic placebo-subtracted reduction of up to 13.6/11.5 mmHg at a dose of 300 mg irbesartan and 12.5 mg hydrochlorothiazide. Once daily dosing with 150 mg irbesartan and 12.5 mg hydrochlorothiazide gave systolic/diastolic mean placebo-adjusted blood pressure reductions at trough (24 hours post-dosing) of 12.9/6.9 mmHg.
In patients not adequately controlled (SeDBP ≥ 90 mmHg) on irbesartan (up to 300 mg) alone, the addition of 12.5 mg hydrochlorothiazide gave an added reduction of up to 6.1 mmHg in trough (24 hours) diastolic blood pressure.
In patients not adequately controlled (SeDBP 93-120 mmHg) on 25 mg hydrochlorothiazide alone, the addition of irbesartan (75-150 mg) gave an added systolic/diastolic mean reduction of 11.1/7.2 mmHg.
Analysis of age, gender and race subgroups of patients showed that men and women, and patients over and under 65 years of age, had generally similar responses.
The effect of irbesartan is apparent after the first dose, substantially present within 1-2 weeks and reaches a maximal effect within 4-6 weeks. In long-term studies the effect of irbesartan appeared to be maintained for more than one year. After withdrawal of irbesartan, blood pressure gradually returned towards baseline; no rebound was observed. There was essentially no change in average heart rate in irbesartan-treated patients in controlled trials.

Hypertension and type II diabetic renal disease.

The Irbesartan Diabetic Nephropathy Trial (IDNT) was a multicentre, randomised, controlled, double-blind, morbidity and mortality trial comparing irbesartan, amlodipine and placebo. In 1,715 hypertensive patients with type II diabetes (proteinuria ≥ 900 mg/day and serum creatinine 110-265 micromol/L in men and 90-265 micromol/L in women) the long-term effects (mean 2.6 years) of irbesartan on the progression of renal disease and all-cause mortality were examined. In addition, a secondary end-point, the effect of irbesartan on the risk of fatal or non-fatal cardiovascular events was assessed. Patients were randomised to receive irbesartan 75 mg, amlodipine 2.5 mg or matching placebo once-daily. Patients were then titrated to a maintenance dose of 300 mg irbesartan, 10 mg amlodipine or placebo as tolerated. Additional antihypertensive agents (excluding ACE inhibitors, angiotensin II receptor antagonists and calcium channel blockers) were added as needed to help achieve blood pressure goal (≤ 135/85 or 10 mmHg reduction in systolic blood pressure if higher than 160 mmHg) for patients in all groups. Irbesartan demonstrated a 20% relative risk reduction in the composite primary endpoint (first occurrence of any of the following: doubling of serum creatinine, end-stage renal disease or all-cause mortality) compared to placebo (95% CI (3%, 34%), p = 0.023) and a 23% relative risk reduction compared to amlodipine (95% CI (7%, 37%), p = 0.006). When the individual components of the primary endpoint were analysed, no effect in all cause mortality was observed, while a positive trend in the reduction in ESRD and a significant reduction in doubling of serum creatinine were observed. Similar blood pressure was achieved in the irbesartan and amlodipine groups. There was no significant difference in the assessment of fatal or non-fatal cardiovascular events (cardiovascular death, non-fatal myocardial infarction, hospitalisation for heart failure, permanent neurologic deficit attributed to stroke or above-the-ankle amputation) among the three treatment groups.
The study of the Effects of Irbesartan on MicroAlbuminuria in Hypertensive Patients with Type II Diabetes Mellitus (IRMA 2) was a multicentre, randomised, placebo-controlled, double-blind morbidity study, conducted in 590 hypertensive patients with type II diabetes, microalbuminuria (20-200 microgram/min; 30-300 mg/day) and normal renal function (serum creatinine ≤ 130 micromol/L in males and ≤ 100 micromol/L in females). The study examined as a primary endpoint the long-term effects (2 years) of irbesartan on the progression to (overt) proteinuria (urinary albumin excretion rate [AER] > 200 microgram/min [> approximately 300 mg/day] and an increase in AER of at least 30% from baseline). In addition, after one and two years of treatment, the effect of irbesartan on the change in overnight AER and the change in 24-hour creatinine clearance was assessed. Patients were randomised to receive irbesartan 150 mg, irbesartan 300 mg or matching placebo once daily. Additional antihypertensive agents (excluding ACE inhibitors, angiotensin II receptor antagonists and dihydropyridine calcium blockers) were added as needed to help achieve blood pressure goal (≤ 135/85 mmHg) for patients in all groups. Irbesartan 300 mg demonstrated a 70% relative risk reduction in the development of clinical (overt) proteinuria compared to placebo (95% CI (39%, 86%), p = 0.0004). Irbesartan 150 mg demonstrated a 39% relative risk reduction in the development of proteinuria compared to placebo (95% CI (-8%, 66%), p = 0.085). In the intent to treat analysis, when the primary endpoint is adjusted for urinary albumin excretion rate and mean arterial pressure, irbesartan 300 mg demonstrated a 68% relative risk reduction, (95% CI (35%, 85%), p = 0.002). The slowing of progression to clinical (overt) proteinuria was evident as early as three months and continued over the 2 year period. The decline in 24-hour creatinine clearance did not differ significantly among the 3 groups. Regression to normoalbuminuria (< 20 microgram/min; < 30 mg/day) was more frequent in the irbesartan 300 mg group (34%) than in the placebo group (21%).
The adverse experiences reported in these two studies are summarised, see Section 4.8 Adverse Effects (Undesirable Effects), Hypertension and type II diabetic renal disease; Section 4.4 Special Warnings and Precautions for Use, Effects on laboratory tests.

5.2 Pharmacokinetic Properties

Irbesartan is an orally active agent and does not require biotransformation for its activity.

Absorption.

Following oral administration, irbesartan is rapidly and well absorbed. In studies employing an injection and an oral solution containing radio-labelled irbesartan the average absolute oral bioavailability of irbesartan was 60-80%. Median peak plasma concentrations generally occurred 1.5-2 hours after oral administration of irbesartan capsules and tablets. Food did not affect the bioavailability.

Distribution.

Irbesartan is 90% protein-bound in the plasma and has negligible binding to cellular components of blood. The volume of distribution (V) is 53-93 litres.

Metabolism.

Following oral or intravenous administration of 14C-irbesartan more than 80% of the circulating plasma radioactivity was attributable to unchanged irbesartan. Irbesartan is metabolised by the liver via glucuronide conjugation and oxidation. The major circulating metabolite is irbesartan glucuronide (~ 6%). Irbesartan undergoes oxidation primarily by the cytochrome P450 isoenzyme CYP2C9; isoenzyme CYP3A4 has negligible effect. It is not metabolised by, nor does it substantially induce or inhibit most isoenzymes commonly associated with drug metabolism (i.e. CYP1A1, CYP1A2, CYP2A6, CYP2B6, CYP2D6 or CYP2E1). Irbesartan does not induce nor inhibit isoenzyme CYP3A4.

Excretion.

Irbesartan and its metabolites are excreted by both biliary and renal routes. About 20% of the administered radioactivity after an oral or intravenous dose of 14C-irbesartan was recovered in urine with the remainder in the faeces. Less than 2% of the dose was excreted in urine as unchanged irbesartan.
The terminal elimination half-life (t½) of irbesartan averaged 11-15 hours over a range of doses following multiple oral dosing. The total body clearance of intravenously administered irbesartan was 157 to 176 mL/min, of which 3.0-3.5 mL/min was renal clearance. Irbesartan exhibits linear pharmacokinetics over the therapeutic dose range. Steady-state plasma concentrations are attained within 3 days after initiation of a once-daily dosing regimen. Limited accumulation (< 20%) is observed in plasma upon repeated once-daily dosing.

Special populations.

In male and female hypertensive subjects, higher (11-44%) plasma concentrations of irbesartan were observed in females than in males, although, following multiple dosing, males and females did not show differences in either accumulation or elimination half-life. No gender-specific differences in clinical effect have been observed.
In elderly (male and female) normotensive subjects (65-80 years) with clinically normal renal and hepatic function, the plasma AUC and peak plasma concentrations (Cmax) of irbesartan are approximately 20%-50% greater than those observed in younger subjects (18-40 years). Regardless of age, the elimination half-life is comparable. No significant age-related differences in clinical effect have been observed.
In black and white normotensive subjects, the plasma AUC and t½ of irbesartan are approximately 20-25% greater in blacks than in whites; the peak plasma concentrations (Cmax) of irbesartan are essentially equivalent.
In patients with renal impairment (regardless of degree), and in haemodialysis patients, the pharmacokinetics of irbesartan are not significantly altered. Irbesartan is not removed by haemodialysis.
In patients with hepatic insufficiency due to mild to moderate cirrhosis, the pharmacokinetics of irbesartan are not significantly altered.

5.3 Preclinical Safety Data

Genotoxicity.

Irbesartan was not genotoxic in a series of assays for mutagenic and clastogenic effects.

Carcinogenicity.

The carcinogenic potential of irbesartan was assessed in two 104-week studies in mice and rats. No carcinogenic potential was observed in either species at doses of up to 500 mg/kg/day (male rats) and 1000 mg/kg/day (mice and female rats). The AUC based exposure levels were 3-6 fold higher in mice, 3-fold higher in male rats and 25-fold higher in female rats than that of humans at the maximum recommended clinical dose of 300 mg/day.

4 Clinical Particulars

4.1 Therapeutic Indications

Irbesartan is indicated for:
treatment of hypertension;
delaying the progression of renal disease in hypertensive type II diabetics with persistent micro-albuminuria (≥ 30 mg per 24 hours) or urinary protein in excess of 900 mg per 24 hours.

4.3 Contraindications

Known hypersensitivity to irbesartan or any other ingredient in these tablets (see Section 6.1 List of Excipients).
Do not co-administer irbesartan with aliskiren-containing medicines in patients with diabetes or with moderate to severe renal impairment.
Do not co-administer irbesartan with ACE inhibitors in patients with diabetic nephropathy.
Pregnancy (see Section 4.6 Fertility, Pregnancy and Lactation, Use in pregnancy).

4.4 Special Warnings and Precautions for Use

Hypotension: volume-depleted patients.

Irbesartan has been rarely associated with hypotension in hypertensive patients without other co-morbid conditions. Symptomatic hypotension, as with ACE inhibitors, may be expected to occur in sodium/volume-depleted patients such as those treated vigorously with diuretics and/or salt restriction or on haemodialysis. Volume and/or sodium-depletion should be corrected before initiating therapy with irbesartan or a lower starting dose (e.g. 75 mg) should be considered. Patients undergoing haemodialysis should receive a starting dose of 75 mg and the dose should be adjusted according to B.P. response.

Renal function.

As a consequence of inhibiting the renin-angiotensin-aldosterone system, changes in renal function may be anticipated in susceptible individuals. In patients whose renal function depends on the activity of the renin-angiotensin-aldosterone system (e.g. hypertensive patients with renal artery stenosis in one or both kidneys or patients with severe congestive heart failure), treatment with drugs that affect this system has been associated with oliguria and/or progressive azotemia and (rarely) with acute renal failure and/or death. The possibility of a similar effect occurring with the use of an angiotensin II receptor antagonist, including irbesartan cannot be excluded.
In hypertensive type II diabetic patients with proteinuria (≥ 900 mg/day), a population which has a high risk of renal artery stenosis, no patient treated with irbesartan in IDNT had an early acute rise in serum creatinine attributable to renal artery disease (see Section 5.1 Pharmacodynamic Properties, Clinical trials).
Experience is limited with irbesartan in patients with moderate to severe renal impairment; careful monitoring of renal function and potassium in such patients is advised.

Hyperkalaemia.

While hyperkalaemia in uncomplicated patients with hypertension has not been reported with irbesartan, hyperkalaemia may occur during treatment with other drugs that affect the renin-angiotensin-aldosterone system, especially in the presence of renal impairment and/or heart failure. Adequate monitoring of serum potassium in patients at risk is recommended.

Dual blockade of the renin-angiotensin-aldosterone system (RAAS).

Dual blockade of the RAAS by combining irbesartan with an ACE inhibitor or with aliskiren is not recommended since there are increased risks of hypotension, hyperkalemia and changes in renal function compared to monotherapy. The use of irbesartan in combination with aliskiren is contraindicated in patient with diabetes mellitus or renal impairment (see Section 4.3 Contraindications).
The use of irbesartan in combination with an ACE inhibitor is contraindicated in patients with diabetic nephropathy (see Section 4.3 Contraindications; Section 4.5 Interactions with Other Medicines and Other Forms of Interactions).

Psoriasis.

The use of irbesartan in patients with psoriasis or a history of psoriasis should be carefully weighed as it may exacerbate psoriasis.

Cardiac disorders.

The safety of irbesartan in the presence of heart failure has not been fully defined. Sudden death has occurred in some studies of patients with heart failure and, although such deaths may have reflected the natural history of the underlying heart failure, caution is recommended when treating such patients with irbesartan.
At this time, experience is limited with irbesartan in the treatment of patients with ventricular dysfunction or cardiac arrhythmias; caution is advised.

Use in renal impairment.

See comments under Renal function above and see Section 4.2 Dose and Method of Administration.

Paediatric use.

Safety and effectiveness in paediatric patients have not been established.

Use in the elderly.

Among patients who received irbesartan in clinical studies, no overall differences in efficacy or safety were observed between older patients (65 years or older) and younger patients.

Effects on laboratory tests.

No clinically significant changes in laboratory test parameters occurred in controlled clinical studies of hypertension. No special monitoring of laboratory parameters is necessary for patients with uncomplicated essential hypertension. Monitoring of potassium levels and renal function is recommended for patients with heart failure and those with moderate to severe renal impairment (see Section 4.4 Special Warnings and Precautions for Use, above).
In two clinical studies of patients with hypertension and type II diabetic renal disease (IDNT and IRMA 2) the following was reported.

Hyperkalaemia.

In IDNT the percent of subjects with hyperkalaemia (> 6 mmol/L) was 18.6% in the irbesartan group compared to 6.0% in the placebo group. In IRMA 2, the percent of subjects with hyperkalaemia (> 6 mmol/L) was 1.0% in the irbesartan groups and none in the placebo group. In IDNT discontinuations due to hyperkalaemia in the irbesartan group were 2.1% vs. 0.36% in the placebo group. In IRMA 2, discontinuations due to hyperkalaemia in the irbesartan groups were 0.5% vs. none in the placebo group.

4.5 Interactions with Other Medicines and Other Forms of Interactions

Based on in vitro data, no interactions would be expected to occur with drugs whose metabolism is dependent upon cytochrome P450 isoenzymes CYP1A1, CYP1A2, CYP2A6, CYP2B6, CYP2D6, CYP2E1 or CYP3A4. Irbesartan is primarily metabolised by CYP2C9, however, during clinical interaction studies, no significant pharmacodynamic interactions were observed when irbesartan was co-administered with warfarin (a drug metabolised by CYP2C9).
Irbesartan does not affect the pharmacokinetics of digoxin. The pharmacokinetics of irbesartan is not affected by co-administration with nifedipine or hydrochlorothiazide.

Potassium-sparing diuretics, potassium supplements, potassium containing salt substitutes.

Based on experience with the use of other drugs that affect the renin-angiotensin system, concomitant use of potassium-sparing diuretics, potassium supplements, salt substitutes containing potassium or other medicinal products that may increase kalaemia with irbesartan may lead to increases in serum potassium sometimes severe, and requires close monitoring of serum potassium.

Lithium.

Increases in serum lithium concentrations and lithium toxicity have been reported with concomitant use of irbesartan. Monitor lithium levels in patients receiving irbesartan and lithium.

Combination use of ACE inhibitors or angiotensin receptor antagonists, anti-inflammatory drugs and thiazide diuretics.

Concomitant use of a renin-angiotensin system inhibiting drug (ACE-inhibitor or angiotensin receptor antagonist) and an anti-inflammatory drug (NSAID, including COX-2 inhibitor) alone or with a thiazide diuretic may increase the risk of renal impairment, including possible acute renal failure. These effects are usually reversible. This includes use in fixed-combination products containing more than one class of drug. The combination of these agents should be administered with caution, especially in the elderly, volume-depleted and in patients with pre-existing renal impairment. Renal function (serum creatinine) should be monitored after initiation of concomitant therapy and periodically thereafter. The antihypertensive effect of angiotensin II receptor antagonists, including irbesartan, may be attenuated by NSAIDs including selective COX-2 inhibitors.
The use of irbesartan in combination with an ACE inhibitor is contraindicated in patients with diabetic nephropathy and is not recommended in other patients (see Section 4.3 Contraindications; Section 4.4 Special Warnings and Precautions for Use).

Renin inhibitor.

The combination of irbesartan with aliskiren-containing medicinal products is contraindicated in patients with diabetes mellitus or moderate to severe renal impairment and is not recommended in other patients (see Section 4.3 Contraindications).

Angiotensin-converting enzyme inhibitors (ACE inhibitors).

The combination of irbesartan with ACE inhibitors is not recommended.

4.6 Fertility, Pregnancy and Lactation

Effects on fertility.

Fertility and reproductive performance were not affected in studies of male and female rats at oral doses of up to 650 mg/kg/day (approximately 3 (male) and 8 (female) fold higher exposure, based on AUC, than that of humans at the maximum recommended clinical dose of 300 mg/day).
(Category D)
Several dozen cases have been reported in the world literature in patients who were taking angiotensin-converting enzyme inhibitors. When pregnancy is detected, irbesartan should be discontinued as soon as possible.
The use of drugs that act directly on the renin-angiotensin system during the second and third trimesters of pregnancy have been associated with foetal and neonatal injury, including hypotension, neonatal skull hypoplasia, anuria, reversible or irreversible renal failure and death. Oligohydramnios has also been reported, presumably resulting from decreased foetal renal function; oligohydramnios in this setting has been associated with foetal limb contractures, craniofacial deformation and hypoplastic lung development.
Prematurity, intrauterine growth retardation and patent ductus arteriosus have also been reported, although it is not clear whether these occurrences were due to exposure to the drug.
These adverse effects do not appear to have resulted from intrauterine drug exposure that has been limited to the first trimester. Mothers whose embryos and foetuses are exposed to an angiotensin II receptor antagonist only during the first trimester should be so informed. Nonetheless, when patients become pregnant, physicians should have the patient discontinue the use of irbesartan as soon as possible.
Infants with histories of in utero exposure to an angiotensin II receptor antagonist should be closely observed for hypotension, oliguria and hyperkalaemia.
When pregnant rats were treated with irbesartan from day 0 to day 20 of gestation, at doses of 50 mg/kg/day and higher, transient effects (increased renal pelvic cavitation, hypoureter or subcutaneous oedema) were noted in full term rat foetuses but not in the young animals necropsied after 6 weeks of age. In pregnant rabbits, at doses of 30 mg/kg/day, maternal mortality, abortion and early foetal resorptions were noted. No teratogenic effects were observed in the rat or rabbit.
Irbesartan is excreted in the milk of lactating rats. It is not known whether irbesartan or its metabolites are excreted in human milk. A decision should be made whether to discontinue breast feeding or to discontinue the drug, taking into account the importance of irbesartan to the therapy of the mother and the potential risk to the infant.

4.8 Adverse Effects (Undesirable Effects)

Hypertension.

Irbesartan has been evaluated for safety in approximately 5000 subjects in clinical studies, including 1300 hypertensive patients treated for over 6 months and over 400 patients treated for one year or more. Adverse events in patients receiving irbesartan were generally mild and transient with no relationship to dose. The incidence of adverse events was not related to age, gender or race.
In placebo-controlled clinical studies, including 1965 irbesartan-treated patients (usual duration of treatment 1 to 3 months), discontinuations due to any clinical or laboratory adverse event were 3.3% for irbesartan-treated patients and 4.5% for placebo-treated patients (p = 0.029).
Clinical adverse events, occurring in at least 1% of patients treated with irbesartan in placebo controlled trials are shown in Table 1. The incidence of the same adverse events in the placebo control group is also shown.
Adverse reactions that occurred in 2 or more hypertensive patients in clinical trials involving 3396 patients have been classified using standard terminology and in the following listing are categorised by body system and listed in order of decreasing frequency according to the following definitions: common adverse reactions are those occurring on one or more occasions in at least 1/100 but less than 1/10 patients; uncommon adverse reactions are those occurring in at least 1/1000 but less than 1/100 patients; rare adverse reactions are those occurring in less than 1/1000 patients.

Cardiovascular.

Uncommon: Subjective rhythm disturbance, flushing, ECG abnormality, cardiac murmur, cardiac rhythm disturbance, orthostatic hypotension, atrial rhythm disturbance, bradycardia, hypotension.
Rare: Syncope, conduction disorder, myocardial infarction.

Dermatological.

Uncommon: Pruritus, facial erythema.
Rare: Dermatitis, acne, scalp-hair abnormality.

Endocrine/ metabolic/ electrolyte imbalance.

Uncommon: Sexual dysfunction, libido change.
Rare: Breast disorder, gout, hot flashes.

Gastrointestinal.

Uncommon: Constipation, flatulence, dry mouth, abdomen distention.
Rare: Abnormal stool, decreased appetite, increased appetite, oral lesion, dysphagia, oesophagitis.

General.

Uncommon: Weakness, hyperhidrosis, malaise, weight gain.
Rare: Cold sensation, warmth sensation, pain.

Haematopoietic.

Rare: Anaemia.

Immunology/ sensitivity disorder.

Uncommon: Upper extremity oedema.
Rare: Head/ neck oedema.

Musculoskeletal/ connective tissue.

Uncommon: Muscle cramp, swelling extremity.
Rare: Arthritis, muscle ache, myalgia, extremity weakness, stiffness lower extremity.

Nervous system.

Uncommon: Orthostatic dizziness, numbness, sleep disturbance, depression, emotion labile/ disturbance, somnolence, vertigo, paraesthesia.
Rare: Stress related disorder, tremor, coordination disturbance, disturbing dreams.

Renal/ genitourinary.

Uncommon: Urination abnormality.

Respiratory.

Uncommon: Epistaxis, dyspnoea.

Special senses.

Uncommon: Vision disturbance, hearing abnormality.
Rare: Eye disturbance-other, eyelid abnormality, visual field abnormality, medication bad taste, taste disturbance.

Hypertension and type II diabetic renal disease.

In clinical studies (see Section 5.1 Pharmacodynamic Properties, Clinical trials, Hypertension and type II diabetic renal disease), the adverse experiences were similar to those in clinical trials of hypertensive patients with the exception of orthostatic symptoms (dizziness, orthostatic dizziness and orthostatic hypotension) observed in IDNT (proteinuria ≥ 900 mg/day and serum creatinine from 90-265 micromol/L). In IDNT orthostatic symptoms occurred more frequently in the irbesartan group (dizziness 10.2%, orthostatic dizziness 5.4%, orthostatic hypotension 5.4%) than in the placebo group (dizziness 6.0%, orthostatic dizziness 2.7%, orthostatic hypotension 3.2%). The rates (percents) of discontinuations due to orthostatic symptoms for irbesartan versus placebo were: dizziness 0.3 vs. 0.5; orthostatic dizziness 0.2 vs. 0.0; and orthostatic hypotension, 0.0 vs. 0.0.

Post-marketing experience.

As with other angiotensin-II receptor antagonists, rare cases of hypersensitivity reactions (urticaria, angioedema, anaphylactic reactions including anaphylactic shock) have been reported since the marketing of irbesartan. The following have been reported during post-marketing surveillance: vertigo, asthenia, hyperkalaemia, thrombocytopenia (including thrombocytopenic purpura), myalgia, jaundice, elevated liver function tests, hepatitis, arthralgia, tinnitus, psoriasis (and psoriasis exacerbation) (see Section 4.4 Special Warnings and Precautions for Use), photosensitivity and impaired renal function including cases of renal failure in patients at risk (see Section 4.8 Adverse Effects (Undesirable Effects)).
Rare cases of rhabdomyolysis have been reported in patients receiving angiotensin II receptor blockers.

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 http://www.tga.gov.au/reporting-problems and contact Apotex Medical Information Enquiries/Adverse Drug Reaction Reporting on 1800 195 055.

4.2 Dose and Method of Administration

Blooms the Chemist Irbesartan tablets are intended for oral administration.

Dosage.

Irbesartan may be used either alone or in combination with other antihypertensive agents (e.g. thiazide diuretic, beta-adrenergic blocking agent, long-acting calcium-channel blocking agent).
The usual initial and maintenance dose of irbesartan is 150 mg once daily. Irbesartan may be administered with or without food. Therapy should be adjusted according to blood pressure response. Patients requiring further reduction in blood pressure should have the dose increased to 300 mg once daily.
In patients with hypertension and type II diabetic renal disease, 300 mg of irbesartan once daily is the preferred maintenance dose. Although irbesartan slowed the progression of renal disease in hypertensive patients separately to its effect on blood pressure, this does not remove the clinical requirement for a patient's blood pressure to be adequately controlled. If irbesartan alone is insufficient, then other agents should be added in order to gain blood pressure control.
Irbesartan increases the risk of significant hyperkalaemia in hypertensive patients with type II diabetes and moderate to severe renal insufficiency (see Section 4.8 Adverse Effects (Undesirable Effects); Section 4.4 Special Warnings and Precautions for Use, Effects on laboratory tests, Hyperkalaemia). Serum potassium should be monitored regularly in such patients.
If blood pressure is not adequately controlled with irbesartan alone, a diuretic (e.g. hydrochlorothiazide 12.5 mg daily) or another antihypertensive drug (e.g. beta-adrenergic blocking agent, long-acting calcium channel blocking agent) may be added.

Patients with intravascular volume depletion.

Volume and/or sodium-depletion should be corrected before initiating therapy with irbesartan or a lower starting dose (e.g. 75 mg) should be considered. Patients undergoing haemodialysis should receive a starting dose of 75 mg and the dose should be adjusted according to B.P. response. If the blood pressure is not adequately controlled, the dose can be increased.

Elderly patients.

No dosage reduction is generally necessary in the elderly unless accompanied by uncorrected volume depletion (see Section 4.2 Dose and Method of Administration, Patients with intravascular volume depletion).

Patients with renal impairment.

No dosage reduction is generally necessary in patients with impaired renal function (regardless of degree), unless accompanied by uncorrected volume depletion (see Section 4.2 Dose and Method of Administration, Patients with intravascular volume depletion).

Patients with hepatic impairment.

No dosage reduction is generally necessary in patients with impaired hepatic function (mild to moderate degree) unless accompanied by uncorrected volume depletion (see Section 4.2 Dose and Method of Administration, Patients with intravascular volume depletion).

4.7 Effects on Ability to Drive and Use Machines

The effect of irbesartan on ability to drive and use machines has not been studied. When driving vehicles or operating machines, it should be taken into account that occasionally dizziness or weariness may occur during treatment of hypertension.

4.9 Overdose

Experience in adults exposed to doses of up to 900 mg/day for 8 weeks revealed no toxicity. No specific information is available on the treatment of overdosage with irbesartan. The patient should be closely monitored and the treatment should be symptomatic and supportive. If simple supine positioning is found insufficient to correct hypotension then judicious I.V. volume replacement/ augmentation may be indicated. Irbesartan is not removed from the body by haemodialysis.
For information on the management of overdose, contact the Poisons Information Centre on 131126 (Australia).

7 Medicine Schedule (Poisons Standard)

S4.

6 Pharmaceutical Particulars

6.1 List of Excipients

Lactose monohydrate, croscarmellose sodium, povidone, magnesium stearate, Opadry II complete film coating system 30F58652 white.

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

Blooms the Chemist Irbesartan tablets.

75 mg tablets.

Blister packs (PVC/PVdC/Al) of 30 tablets: AUST R 259883.

150 mg tablets.

Blister packs (PVC/PVdC/Al) of 30 tablets: AUST R 259884.

300 mg tablets.

Blister packs (PVC/PVdC/Al) of 30 tablets: AUST R 259885.
*Not all strengths may be available.

6.6 Special Precautions for Disposal

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

Summary Table of Changes