Irbesartan

AVAPRO is an angiotensin II receptor blocker (ARB) indicated for: Treatment of hypertension, to lower blood pressure. Lowering blood pressure reduces the risk of fatal and nonfatal cardiovascular events, primarily strokes and myocardial infarctions. ( 1.1 ) Treatment of diabetic nephropathy in hypertensive patients with type 2 diabetes, an elevated serum creatinine, and proteinuria. ( 1.2 )

1.1 Hypertension AVAPRO ® is 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. AVAPRO may be used alone or in combination with other antihypertensive agents.

1.2 Nephropathy in Type 2 Diabetic Patients AVAPRO is 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, AVAPRO 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) ] .

AVAPRO 150 mg is a white to off-white, biconvex oval, film-coated tablet debossed with a heart on one side and "2872" on the other. AVAPRO 300 mg is a white to off-white, biconvex oval, film-coated tablet debossed with a heart on one side and "2873" on the other. Tablets: 150 mg, 300 mg ( 3 )

AVAPRO is contraindicated in patients who are hypersensitive to any component of this product. Do not coadminister aliskiren with AVAPRO in patients with diabetes. Hypersensitivity to any component of this product. ( 4 ) Coadministration with aliskiren in patients with diabetes. ( 4 )

Hypotension: Correct volume or salt depletion prior to administration. ( 5.2 ) Monitor renal function and serum potassium. ( 5.3 )

5.1 Fetal Toxicity AVAPRO can cause fetal harm when administered to a pregnant woman. Use of drugs that act on the renin-angiotensin system during the second and third trimesters of pregnancy reduces fetal renal function and increases fetal and neonatal morbidity and death. Resulting oligohydramnios can be associated with fetal lung hypoplasia and skeletal deformations. Potential neonatal adverse effects include skull hypoplasia, anuria, hypotension, renal failure, and death. When pregnancy is detected, discontinue AVAPRO as soon as possible [see Use in Specific Populations (8.1) ] .

5.2 Hypotension in Volume or Salt-Depleted Patients In patients with an activated renin-angiotensin system, such as volume or salt-depleted patients (e.g., those being treated with high doses of diuretics), symptomatic hypotension may occur after initialization of treatment with AVAPRO. Correct volume or salt depletion prior to administration of AVAPRO or use a lower starting dose [see Dosage and Administration (2.4) ] .

5.3 Impaired Renal Function Changes in renal function including acute renal failure can be caused by drugs that inhibit the renin-angiotensin system. Patients whose renal function may depend in part on the activity of the renin-angiotensin system (e.g., patients with renal artery stenosis, chronic kidney disease, severe heart failure, or volume depletion) may be at particular risk of developing acute renal failure or death on AVAPRO. Monitor renal function periodically in these patients. Consider withholding or discontinuing therapy in patients who develop a clinically significant decrease in renal function on AVAPRO [see Drug Interactions (7.3) ] .

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) ] Nephropathy in type 2 diabetic patients: The most common adverse reactions which were more frequent than placebo were hyperkalemia dizziness, orthostatic dizziness, and orthostatic hypotension. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact sanofi-aventis U.S. LLC at 1-800-633-1610 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

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 AVAPRO 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 AVAPRO (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 1.0–3.0 mg/dL), the percent of patients with potassium >6 mEq/L was 18.6% in the AVAPRO group versus 6.0% in the placebo group. Discontinuations due to hyperkalemia in the AVAPRO 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 AVAPRO 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 Postmarketing Experience The following adverse reactions have been identified during postapproval use of AVAPRO. 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. Blood and lymphatic system: Anemia, Thrombocytopenia Ear and labyrinth: Tinnitus Gastrointestinal: Intestinal angioedema Hepatobiliary: Hepatitis, Jaundice Immune system: Anaphylactic reaction including anaphylactic shock Investigations: Increased liver function tests, Increased CPK (Creatine Phosphokinase) Metabolism and nutrition: Hyperkalemia, Hypoglycemia in diabetic patients Skin and subcutaneous tissue: Urticaria, Angioedema (involving swelling of the face, lips, pharynx, and/or tongue)

Lithium: Risk of lithium toxicity. ( 7 ) Nonsteroidal Anti-inflammatory Drugs (NSAIDs) and COX-2 inhibitors: Increased risk of renal impairment. Reduced antihypertensive effects. ( 7 ) Dual blockade of the renin-angiotensin system: Increased risk of renal impairment, hypotension, and hyperkalemia. ( 7 )

7.1 Agents Increasing Serum Potassium Coadministration of AVAPRO 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 Nonsteroidal 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, coadministration 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 AVAPRO and other agents that affect the RAS. Do not coadminister aliskiren with AVAPRO in patients with diabetes. Avoid use of aliskiren with AVAPRO in patients with renal impairment (GFR <60 mL/min).

Lactation: Potential for adverse effects in infants. ( 8.2 )

8.1 Pregnancy Risk Summary AVAPRO can cause fetal harm when administered to a pregnant woman. Use of drugs that act on the renin-angiotensin system during the second and third trimesters of pregnancy reduces fetal renal function and increases fetal and neonatal morbidity and death [see Clinical Considerations ] . Most epidemiologic studies examining fetal abnormalities after exposure to antihypertensive use in the first trimester have not distinguished drugs affecting the renin-angiotensin system from other antihypertensive agents. When pregnancy is detected, discontinue AVAPRO as soon as possible. All pregnancies have a background risk of birth defect, loss or other adverse outcomes regardless of drug exposure. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively. Clinical Considerations Disease-associated maternal and/or embryo-fetal risk Hypertension in pregnancy increases the maternal risk for preeclampsia, gestational diabetes, premature delivery, and delivery complications (e.g., need for cesarean section and postpartum hemorrhage). Hypertension increases the fetal risk for intrauterine growth restriction and intrauterine death. Pregnant women with hypertension should be carefully monitored and managed accordingly. Fetal/neonatal adverse reactions Oligohydramnios in pregnant women who use drugs affecting the renin-angiotensin system in the second and third trimesters of pregnancy can result in the following: reduced fetal renal function leading to anuria and renal failure, fetal lung hypoplasia, skeletal deformations, including skull hypoplasia, hypotension, and death. In the unusual case that there is no appropriate alternative to therapy with drugs affecting the renin-angiotensin system for a particular patient, apprise the mother of the potential risk to the fetus. Perform serial ultrasound examinations to assess the intra-amniotic environment. Fetal testing may be appropriate, based on the week of pregnancy. Patients and physicians should be aware, however, that oligohydramnios may not appear until after the fetus has sustained irreversible injury. If oligohydramnios is observed, consider alternative treatment. Closely observe infants with histories of in utero exposure to AVAPRO for hypotension, oliguria, and hyperkalemia and other symptoms of renal impairment. In neonates with a history of in utero exposure to AVAPRO, if oliguria or hypotension occurs, direct attention toward support of blood pressure and renal perfusion. Exchange transfusion or dialysis may be required as means of reversing hypotension and/or substituting for disordered renal function. Data Animal data Irbesartan crosses the placenta in rats and rabbits. In female rats given irbesartan prior to mating through gestation and lactation at oral doses of 50, 180, or 650 mg/kg/day (1.6 to 21.1 times the maximum recommended human dose (MRHD) based on body surface area), fetuses examined on Gestation Day 20 showed increased incidences of hydroureter and renal pelvic cavitation and/or absence of renal papilla in all irbesartan-treated groups. Subcutaneous edema also occurred in fetuses at maternal doses ≥180 mg/kg/day (5.8 times the MRHD). These anomalies occurred when female rats received irbesartan from prior to mating through Day 20 of gestation but were not observed in pups postnatally in the same study, or when irbesartan was given to pregnant rats only during organogenesis (Gestation Day 6 through Gestation Day 15) at oral doses from 50 to 450 mg/kg/day (up to 14.6 times the MRHD). In addition, no adverse effects on kidney development were observed in pups from dams given irbesartan from Gestation Day 15 through Lactation Day 24 at doses of 50, 180, or 650 mg/kg/day (up to 21.1 times the MRHD). The observed effects are believed to be late gestational effects of the drug. Pregnant rabbits given oral doses of irbesartan of 30 mg/kg/day (1.9 times the MRHD based on body surface area) experienced a high rate of maternal mortality and abortion. Surviving females had a slight increase in early resorptions and a corresponding decrease in live fetuses. Radioactivity was present in the rat and rabbit fetuses during late gestation following oral doses of radiolabeled irbesartan.

8.2 Lactation There are no available data on the presence of irbesartan in human milk, effects on milk production, or the breastfed infant. Irbesartan or some metabolite of irbesartan is secreted in the milk of lactating rats [see Clinical Pharmacology (12.3) ] . Because of the potential for adverse effects on the nursing infant, the use of AVAPRO in breastfeeding women is not recommended.

8.4 Pediatric Use Irbesartan, in a study at a dose of up to 4.5 mg/kg/day, once daily, did not appear to lower blood pressure effectively in pediatric patients ages 6 to 16 years. AVAPRO has not been studied in pediatric patients less than 6 years old.

8.5 Geriatric Use Of 4925 subjects receiving AVAPRO in controlled clinical studies of hypertension, 911 (18.5%) were 65 years and over, while 150 (3.0%) were 75 years and over. No overall differences in effectiveness or safety were observed between these subjects and younger subjects, but greater sensitivity of some older individuals cannot be ruled out. [See Clinical Pharmacology (12.3) and Clinical Studies (14.1) .]

Angiotensin II is a potent vasoconstrictor formed from angiotensin I in a reaction catalyzed by angiotensin-converting enzyme (ACE, kininase II). Angiotensin II is the primary vasoactive hormone of the renin-angiotensin system, and an important component in the pathophysiology of hypertension. It also stimulates aldosterone secretion by the adrenal cortex. Irbesartan blocks the vasoconstrictor and aldosterone-secreting effects of angiotensin II by selectively binding to the AT 1 angiotensin II receptor found in many tissues (e.g., vascular smooth muscle, adrenal gland). There is also an AT 2 receptor in many tissues, but it is not involved in cardiovascular homeostasis. Irbesartan is a specific competitive antagonist of AT 1 receptors with a much greater affinity (more than 8500-fold) for the AT 1 receptor than for the AT 2 receptor and no agonist activity. Blockade of the AT 1 receptor removes the negative feedback of angiotensin II on renin secretion, but the resulting increased plasma renin activity and circulating angiotensin II do not overcome the effects of irbesartan on blood pressure. Irbesartan does not inhibit ACE or renin or affect other hormone receptors or ion channels known to be involved in the cardiovascular regulation of blood pressure and sodium homeostasis.