Idezar Special Precautions

Fetal/Neonatal Morbidity and Mortality: The use of drugs that act directly on the renin-angiotensin-aldosterone system has been associated with fetal 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 fetal renal function; oligohydramnios in this setting has been associated with fetal limb contractures, craniofacial deformation, and hypoplastic lung development. Prematurity, intrauterine growth retardation, and patent ductus arteriosus have also been observed, 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 fetuses are exposed to an angiotensin II receptor antagonist only during the first trimester should be so informed. Discontinue irbesartan as soon as possible when pregnancy is detected.
If oligohydramnios is observed, discontinue irbesartan unless it is considered life saving for the mother. Contraction stress testing (CST), a nonstress test (NST), or biophysical profiling (BPP) may be appropriate, depending upon the week of pregnancy. However, physicians and patients should be aware that oligohydramnios may not appear until after the fetus has sustained irreversible injury.
Infants with history of in utero exposure to an angiotensin II receptor antagonist should be closely observed for hypotension, oliguria and hyperkalemia. If oliguria occurs, attention should be directed toward support of blood pressure and renal perfusion. Exchange transfusion or dialysis may be required as a means of reversing hypotension and/or substituting for disordered renal function.
Hypotension in Volume- or Salt-depleted Patients: Excessive reduction in blood pressure was rarely observed in patients with uncomplicated hypertension. Initiation of antihypertensive therapy may cause symptomatic hypotension in patients with intravascular volume- or sodium-depletion (e.g., those treated vigorously with diuretics or in patients on dialysis). These conditions should be corrected before starting irbesartan therapy, or a lower starting dose should be used.
If hypotension occurs, the patient should be placed in the supine position and, if necessary, administered with intravenous infusion of normal saline. A transient hypotensive response is not a contraindication to further treatment, which usually may be continued without difficulty once the blood pressure has stabilized.
Renal Impairment and Kidney Transplantation: In studies, ACE inhibitors may increase blood urea nitrogen (BUN) and serum creatinine in patients with unilateral or bilateral renal artery stenosis. There has been no known use of irbesartan in patients with unilateral or bilateral renal artery stenosis, but a similar effect should be anticipated.
Periodic monitoring of potassium and creatinine serum levels is recommended when irbesartan is used in patients with impaired renal function.
There is no experience regarding the use of irbesartan in patients with recent kidney transplantation.
Hyperkalemia: Hyperkalemia may occur during irbesartan treatment, especially in the presence of renal impairment, overt proteinuria due to diabetic renal disease, and/or heart failure. Monitor closely serum potassium in patients at risk.
Aortic and Mitral Valve Stenosis, Obstructive Hypertrophic Cardiomyopathy: As with other vasodilators, special caution is indicated in patients suffering from aortic or mitral valve stenosis, or obstructive hypertrophic cardiomyopathy.
Primary Aldosteronism: Generally, patients with primary aldosteronism will not respond to antihypertensive agents acting through inhibition of the renin-angiotensin-aldosterone system; thus, irbesartan use is not recommended.
General: Treatment with drugs that affect the renin-angiotensin-aldosterone system has been associated with acute hypotension, azotemia, oliguria or, rarely, acute renal failure in patients whose vascular tone and renal function depend predominantly on the activity of this system (e.g., patients with severe congestive heart failure or underlying renal disease, including renal artery stenosis). As with any antihypertensive agent, excessive hypotension in patients with ischemic cardiopathy or ischemic cardiovascular disease could result in a myocardial infarction or stroke.
Irbesartan and other angiotensin antagonists are apparently less effective in lowering blood pressure in black people than in non-blacks, possibly because of higher prevalence of low-renin states in the black hypertensive population.
Use in Children: Irbesartan 4.5 mg/kg/day, once daily, did not appear to decrease blood pressure effectively in children 6 to 16 years old. Irbesartan has not been studied in children less than 6 years old.
Use in Elderly: There were no age-related differences in efficacy or safety profile of irbesartan, but greater sensitivity of some older individuals cannot be ruled out.