IRBESARTAN

Irbesartan USP is an angiotensin II receptor (AT1 subtype) antagonist. Irbesartan USP is a non-peptide compound, chemically described as a 2-butyl-3-[p-(o-1H-tetrazol-5-ylphenyl)benzyl]-1,3-diazaspiro[4.4]non-1-en-4-one. Its empirical formula is C25H28N6O, and the structural formula: [image1] Irbesartan USP is a white to off-white crystalline powder with a molecular weight of 428.5. It is a nonpolar compound with a partition coefficient (octanol/water) of 10.1 at pH of 7.4. Irbesartan is slightly soluble in alcohol and methylene chloride and practically insoluble in water. Irbesartan is available for oral administration in unscored tablets containing 75 mg, 150 mg, or 300 mg of Irbesartan USP. Inactive ingredients include: calcium stearate, carboxy methyl cellulose calcium, colloidal silicon dioxide, microcrystalline cellulose and povidone.

1 Hypertension Irbesartan tablets are indicated for the treatment of hypertension, to lower blood pressure. Lowering blood pressure lowers the risk of fatal and non-fatal cardiovascular (CV) events, primarily strokes and myocardial infarction. These benefits have been seen in controlled trials of antihypertensive drugs from a wide variety of pharmacologic classes including this drug. Control of high blood pressure should be part of comprehensive cardiovascular risk management, including, as appropriate, lipid control, diabetes management, antithrombotic therapy, smoking cessation, exercise, and limited sodium intake. Many patients will require more than 1 drug to achieve blood pressure goals. For specific advice on goals and management, see published guidelines, such as those of the National High Blood Pressure Education Program’s Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC). Numerous antihypertensive drugs, from a variety of pharmacologic classes and with different mechanisms of action, have been shown in randomized controlled trials to reduce cardiovascular morbidity and mortality, and it can be concluded that it is blood pressure reduction, and not some other pharmacologic property of the drugs, that is largely responsible for those benefits. The largest and most consistent cardiovascular outcome benefit has been a reduction in the risk of stroke, but reductions in myocardial infarction and cardiovascular mortality also have been seen regularly. Elevated systolic or diastolic pressure causes increased cardiovascular risk, and the absolute risk increase per mmHg is greater at higher blood pressures, so that even modest reductions of severe hypertension can provide substantial benefit. Relative risk reduction from blood pressure reduction is similar across populations with varying absolute risk, so the absolute benefit is greater in patients who are at higher risk independent of their hypertension (for example, patients with diabetes or hyperlipidemia), and such patients would be expected to benefit from more aggressive treatment to a lower blood pressure goal. Some antihypertensive drugs have smaller blood pressure effects (as monotherapy) in black patients, and many antihypertensive drugs have additional approved indications and effects (e.g., on angina, heart failure, or diabetic kidney disease). These considerations may guide selection of therapy. Irbesartan tablets may be used alone or in combination with other antihypertensive agents. 1.2 Nephropathy in Type 2 Diabetic Patients Irbesartan tablets are indicated for the treatment of diabetic nephropathy in patients with type 2 diabetes and hypertension, an elevated serum creatinine, and proteinuria (>300 mg/day). In this population, irbesartan reduces the rate of progression of nephropathy as measured by the occurrence of doubling of serum creatinine or end-stage renal disease (need for dialysis or renal transplantation) [see Clinical Studies (14.2)].

1 General Considerations Irbesartan tablets may be administered with other antihypertensive agents and with or without food. 2.2 Hypertension The recommended initial dose of irbesartan tablets is 150 mg once daily. The dosage can be increased to a maximum dose of 300 mg once daily as needed to control blood pressure [see Clinical Studies (14.1)]. 2.3 Nephropathy in Type 2 Diabetic Patients The recommended dose is 300 mg once daily [see Clinical Studies (14.2)]. 2.4 Dose Adjustment in Volume- and Salt-Depleted Patients The recommended initial dose is 75 mg once daily in patients with depletion of intravascular volume or salt (e.g., patients treated vigorously with diuretics or on hemodialysis) [see Warnings and Precautions (5.2)].

Irbesartan tablets are contraindicated in patients who are hypersensitive to any component of this product. Do not co-administrate aliskiren with irbesartan tablets in patients with diabetes.

The following important adverse reactions are described elsewhere in the labeling: • Hypotension in Volume- or Salt-depleted Patients [see Warnings and Precautions (5.2)] • Impaired Renal Function [see Warnings and Precautions (5.3)] 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. The adverse reaction information from clinical trials does, however, provide a basis for identifying the adverse events that appear to be related to drug use and for approximating rates. Hypertension Irbesartan has been evaluated for safety in more than 4300 patients with hypertension and about 5000 subjects overall. This experience includes 1303 patients treated for over 6 months and 407 patients for 1 year or more. In placebo-controlled clinical trials, the following adverse reactions were reported in at least 1% of patients treated with irbesartan (n=1965) and at a higher incidence versus placebo (n=641), excluding those too general to be informative and those not reasonably associated with the use of drug because they were associated with the condition being treated or are very common in the treated population, include: diarrhea (3% vs 2%), dyspepsia/heartburn (2% vs 1%), and fatigue (4% vs 3%). Irbesartan use was not associated with an increased incidence of dry cough, as is typically associated with ACE inhibitor use. In placebo-controlled studies, the incidence of cough in irbesartan-treated patients was 2.8% versus 2.7% in patients receiving placebo. Nephropathy in Type 2 Diabetic Patients Hyperkalemia: In the Irbesartan Diabetic Nephropathy Trial (IDNT) (proteinuria ≥900 mg/day, and serum creatinine ranging from 1.0 to 3.0 mg/dL), the percent of patients with potassium >6.0 mEq/L was 18.6% in the irbesartan group versus 6.0% in the placebo group. Discontinuations due to hyperkalemia in the irbesartan group were 2.1% versus 0.4% in the placebo group. In IDNT, the adverse reactions were similar to those seen in patients with hypertension with the exception of an increased incidence of orthostatic symptoms which occurred more frequently in the irbesartan versus placebo group: dizziness (10.2% vs 6.0%), orthostatic dizziness (5.4% vs 2.7%) and orthostatic hypotension (5.4% vs 3.2%). 6.2 Post-Marketing Experience The following adverse reactions have been identified during post-approval use of irbesartan. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to estimate reliably their frequency or to establish a causal relationship to drug exposure. Urticaria; angioedema (involving swelling of the face, lips, pharynx, and/or tongue); anaphylactic reaction including anaphylactic shock; increased liver function tests; jaundice; hepatitis; hyperkalemia; thrombocytopenia; increased CPK; tinitus.

1 Agents Increasing Serum Potassium Coadministration of irbesartan with other drugs that raise serum potassium levels may result in hyperkalemia, sometimes severe. Monitor serum potassium in such patients. 7.2 Lithium Increases in serum lithium concentrations and lithium toxicity have been reported with concomitant use of irbesartan and lithium. Monitor lithium levels in patients receiving irbesartan and lithium. 7.3 Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) Including Selective Cyclooxygenase-2 Inhibitors (COX-2 Inhibitors) In patients who are elderly, volume-depleted (including those on diuretic therapy), or with compromised renal function, co-administration of NSAIDs, including selective COX-2 inhibitors, with angiotensin II receptor antagonists (including irbesartan) may result in deterioration of renal function, including possible acute renal failure. These effects are usually reversible. Monitor renal function periodically in patients receiving irbesartan and NSAID therapy. The antihypertensive effect of angiotensin II receptor antagonists, including irbesartan, may be attenuated by NSAIDs including selective COX-2 inhibitors. 7.4 Dual Blockade of the Renin-Angiotensin System (RAS) Dual blockade of the RAS with angiotensin receptor blockers, ACE inhibitors, or aliskiren is associated with increased risks of hypotension, hyperkalemia, and changes in renal function (including acute renal failure) compared to monotherapy. Most patients receiving the combination of two RAS inhibitors do not obtain any additional benefit compared to monotherapy. In general, avoid combined use of RAS inhibitors. Closely monitor blood pressure, renal function and electrolytes in patients on irbesartan and other agents that affect the RAS. Do not co-administer aliskiren with irbesartan in patients with diabetes. Avoid use of aliskiren with irbesartan in patients with renal impairment (GFR <60 mL/min).