"What are angiotensin receptor blockers (ARBs) and how do they work?
The class of drugs called angiotensin receptor blockers (ARBs), as the class name suggests, are drugs that block the action of angiotensin. Specifically, ARBs preve"...
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. Treatment with AVAPRO was well-tolerated, with an incidence of adverse events similar to placebo. These events generally were mild and transient with no relationship to the dose of AVAPRO.
In placebo-controlled clinical trials, discontinuation of therapy due to a clinical adverse event was required in 3.3% of patients treated with AVAPRO, versus 4.5% of patients given placebo.
In placebo-controlled clinical trials, the following adverse event experiences 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%).
The following adverse events occurred at an incidence of 1% or greater in patients treated with irbesartan, but were at least as frequent or more frequent in patients receiving placebo: abdominal pain, anxiety/nervousness, chest pain, dizziness, edema, headache, influenza, musculoskeletal pain, pharyngitis, nausea/vomiting, rash, rhinitis, sinus abnormality, tachycardia, and urinary tract infection.
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.
The incidence of hypotension or orthostatic hypotension was low in irbesartantreated patients (0.4%), unrelated to dosage, and similar to the incidence among placebo-treated patients (0.2%). Dizziness, syncope, and vertigo were reported with equal or less frequency in patients receiving irbesartan compared with placebo.
In addition, the following potentially important events occurred in less than 1% of the 1965 patients and at least 5 patients (0.3%) receiving irbesartan in clinical studies, and those less frequent, clinically significant events (listed by body system). It cannot be determined whether these events were causally related to irbesartan:
Body as a Whole: fever, chills, facial edema, upper extremity edema
Renal/Genitourinary: abnormal urination, prostate disorder
Special Senses: vision disturbance, hearing abnormality, ear infection, ear pain, conjunctivitis, other eye disturbance, eyelid abnormality, ear abnormality
Nephropathy In Type 2 Diabetic Patients
In clinical studies in patients with hypertension and type 2 diabetic renal disease, the adverse drug experiences were similar to those seen in patients with hypertension with the exception of an increased incidence of orthostatic symptoms (dizziness, orthostatic dizziness, and orthostatic hypotension) observed in IDNT (proteinuria ≥ 900 mg/day, and serum creatinine ranging from 1.0-3.0 mg/dL). In this trial, orthostatic symptoms occurred more frequently in the AVAPRO 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 following adverse reactions have been identified during post-approval 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. Decisions to include these reactions in labeling are typically based on one or more of the following factors: (1) seriousness of the reaction, (2) frequency of reporting, or (3) strength of causal connection to AVAPRO.
The following have been reported: urticaria; angioedema (involving swelling of the face, lips, pharynx, and/or tongue); increased liver function tests; jaundice; hepatitis; hyperkalemia, and thrombocytopenia.
Impaired renal function, including cases of renal failure, has been reported.
Laboratory Test Findings
In controlled clinical trials, clinically important differences in laboratory tests were rarely associated with administration of AVAPRO.
Creatinine, Blood Urea Nitrogen
Minor increases in blood urea nitrogen (BUN) or serum creatinine were observed in less than 0.7% of patients with essential hypertension treated with AVAPRO alone versus 0.9% on placebo. (See PRECAUTIONS: Impaired Renal Function.)
Mean decreases in hemoglobin of 0.2 g/dL were observed in 0.2% of patients receiving AVAPRO compared to 0.3% of placebo-treated patients. Neutropenia ( < 1000 cells/mm³ ) occurred at similar frequencies among patients receiving AVAPRO (0.3%) and placebo-treated patients (0.5%).
Nephropathy In Type 2 Diabetic Patients
In IDNT (proteinuria ≥ 900 mg/day, and serum creatinine ranging from 1.0-3.0 mg/dL), the percent of patients with hyperkalemia ( > 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.
Read the Avapro (irbesartan) Side Effects Center for a complete guide to possible side effects
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 Avapro and lithium.
In vitro studies show significant inhibition of the formation of oxidized irbesartan metabolites with the known cytochrome CYP 2C9 substrates/inhibitors sulphenazole, tolbutamide and nifedipine. However, in clinical studies the consequences of concomitant irbesartan on the pharmacodynamics of warfarin were negligible. Based on in vitro data, no interaction would be expected with drugs whose metabolism is dependent upon cytochrome P450 isoenzymes 1A1, 1A2, 2A6, 2B6, 2D6, 2E1, or 3A4.
In separate studies of patients receiving maintenance doses of warfarin, hydrochlorothiazide, or digoxin, irbesartan administration for 7 days had no effect on the pharmacodynamics of warfarin (prothrombin time) or pharmacokinetics of digoxin. The pharmacokinetics of irbesartan were not affected by coadministration of nifedipine or hydrochlorothiazide.
Concomitant use of potassium-sparing diuretics, potassium supplements, or salt substitutes containing potassium may lead to increases in serum potassium.
Non-Steroidal Anti-Inflammatory Agents 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.
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 AVAPRO 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 AVAPRO in patients with diabetes. Avoid use of aliskiren with AVAPRO in patients with renal impairment (GFR < 60 mL/min).
Read the Avapro Drug Interactions Center for a complete guide to possible interactions
Last reviewed on RxList: 7/15/2014
This monograph has been modified to include the generic and brand name in many instances.
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