Irbesartan and hydrochlorothiazide

7 DRUG INTERACTIONS NSAIDs and selective COX-2 inhibitors: Can reduce diuretic, natriuretic of diuretic, may lead to increased risk of renal impairment and reduced antihypertensive effect. Monitor renal function periodically. ( 7 ) Dual blockade of the renin-angiotensin system: Increased risk of renal impairment, hypotension, and hyperkalemia. ( 7 ) Antidiabetic drugs: Dosage adjustment of antidiabetic may be required. ( 7 ) Cholestyramine and colestipol: Reduced absorption of thiazides. ( 7 ) Lithium: Increases in serum lithium concentrations and lithium toxicity. ( 7 ) Carbamazepine: Increased risk of hyponatremia. ( 7 )

7.1 Nonsteroidal Anti-inflammatory Agents Including Selective Cyclooxygenase-2 Inhibitors (COX-2 Inhibitors) Irbesartan 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. Therefore, monitor renal function and blood pressure periodically in patients receiving irbesartan and NSAID therapy.

Hydrochlorothiazide Administration of a nonsteroidal anti-inflammatory agent, including a selective COX-2 inhibitor can reduce the diuretic, natriuretic, and antihypertensive effects of loop, potassium-sparing, and thiazide diuretics. Therefore, when AVALIDE (irbesartan and hydrochlorothiazide) tablets and nonsteroidal anti-inflammatory agents are used concomitantly, the patient should be observed closely to determine if the desired effect of the diuretic is obtained.

7.2 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. Closely monitor blood pressure, renal function, and electrolytes in patients on AVALIDE and other agents that affect the RAS. In most patients no benefit has been associated with using two RAS inhibitors concomitantly. In general, avoid combined use of RAS inhibitors. Do not coadminister aliskiren with AVALIDE in patients with diabetes.

Avoid use of aliskiren with AVALIDE in patients with renal impairment (GFR <60 mL/min).

7.3 Agents Increasing Serum Potassium Coadministration of AVALIDE with other drugs that raise serum potassium levels may result in hyperkalemia, sometimes severe. Monitor serum potassium in such patients.

7.4 Antidiabetic Drugs (oral agents and insulin) Dosage adjustment of the antidiabetic drug may be required when coadministered with hydrochlorothiazide.

7.5 Cholestyramine and Colestipol Resins Absorption of hydrochlorothiazide is impaired in the presence of anionic exchange resins. Stagger the dosage of hydrochlorothiazide and the resin such that AVALIDE is administered at least 4 hours before or 4 to 6 hours after the administration of the resin.

7.6 Lithium Increases in serum lithium concentrations and lithium toxicity have been reported with concomitant use of irbesartan or thiazide diuretics. Monitor lithium levels in patients receiving AVALIDE and lithium.

7.7 Carbamazepine Concomitant use of carbamazepine and hydrochlorothiazide has been associated with the risk of symptomatic hyponatremia. Monitor electrolytes during concomitant use.

8.1 Pregnancy Risk Summary AVALIDE 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 AVALIDE 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. 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. Closely observe infants with histories of in utero exposure to AVALIDE for hypotension, oliguria, and hyperkalemia and other symptoms of renal impairment. In neonates with a history of in utero exposure to AVALIDE, 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.

Thiazides cross the placenta, and use of thiazides during pregnancy is associated with a risk of fetal or neonatal…