Amlodipine and benazepril hydrochloride capsules can cause fetal harm when administered to a pregnant woman. Use of drugs that act on the RAS during the second and third trimesters of pregnancy reduces fetal renal function and increases fetal and neonatal morbidity and death. Most epidemiologic studies examining fetal abnormalities after exposure to antihypertensive use in the first trimester have not distinguished drugs affecting the RAS from other antihypertensive agents.
When pregnancy is detected, discontinue amlodipine and benazepril hydrochloride capsules as soon as possible.
The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. 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.
Disease-associated maternal and/or embryo/fetal risk
Hypertension in pregnancy increases the maternal risk for pre-eclampsia, gestational diabetes, premature delivery, and delivery complications (e.g., need for cesarean section, and post-partum 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 gestation. 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 drug treatment. Closely observe neonates with histories of in utero exposure to amlodipine and benazepril hydrochloride capsules for hypotension, oliguria, and hyperkalemia. In neonates with a history of in utero exposure to amlodipine and benazepril hydrochloride capsules, if oliguria or hypotension occurs, support blood pressure and renal perfusion. Exchange transfusions or dialysis may be required as a means of reversing hypotension and replacing renal function.
Benazepril and Amlodipine:
When rats received benazepril: amlodipine at doses ranging from 5:2.5 to 50:25 mg/kg/day, dystocia was observed at an increasing dose-related incidence at all doses tested. On a body surface area basis, the 2.5 mg/kg/day dose of amlodipine is twice the amlodipine dose delivered when the maximum recommended dose of amlodipine and benazepril hydrochloride capsules is given to a 60 kg patient. Similarly, the 5 mg/kg/day dose of benazepril is approximately equivalent with the benazepril dose delivered when the maximum recommended dose of amlodipine and benazepril hydrochloride capsules is given to a 60 kg patient. No teratogenic effects were seen when benazepril and amlodipine were administered in combination to pregnant rats or rabbits. Rats received doses of up to 50:25 mg (benazepril: amlodipine)/kg/day (12 times the MRHD on a body surface area basis, assuming a 60 kg patient). Rabbits received doses of up to 1.5:0.75 mg/kg/day (equivalent to the maximum recommended dose of amlodipine and benazepril hydrochloride capsules given to a 60 kg patient).
Minimal amounts of unchanged benazepril and of benazeprilat are excreted into the breast milk of lactating women treated with benazepril, so that a newborn child ingesting nothing but breast milk would receive less than 0.1% of the maternal doses of benazepril and benazeprilat. Limited available data from a published clinical lactation study reports that amlodipine is present in human milk at an estimated median relative infant dose of 4.2%. No adverse effects of amlodipine on the breastfed infant have been observed. There is no available information on the effects of amlodipine or benazepril on milk production.
Safety and effectiveness in pediatric patients have not been established.
In geriatric patients, exposure to amlodipine is increased, thus consider lower initial doses of amlodipine and benazepril hydrochloride [see Clinical Pharmacology (12.3)].
Of the total number of patients who received amlodipine and benazepril hydrochloride in U.S. clinical studies of amlodipine and benazepril hydrochloride, over 19% were 65 years or older while about 2% were 75 years or older. Overall differences in effectiveness or safety were not observed between these patients and younger patients. Clinical experience has not identified differences in responses between the elderly and younger patients, but greater sensitivity of some older individuals cannot be ruled out.
Exposure to amlodipine is increased in patients with hepatic insufficiency, thus consider using lower doses of amlodipine and benazepril hydrochloride capsules [see Clinical Pharmacology (12.3)].
In patients with severe renal impairment systemic exposure to benazepril is increased. The recommended dose of benazepril in this subgroup is 5 mg which is not an available strength with amlodipine and benazepril hydrochloride capsules. Amlodipine and benazepril hydrochloride capsules are not recommended in patients with severe renal impairment. No dose adjustment of amlodipine and benazepril hydrochloride capsules is needed in patients with mild or moderate impairment of renal function [see Dosage and Administration (2.2), Warnings and Precautions (5.7) and Clinical Pharmacology (12.3)].
Only a few cases of human overdose with amlodipine have been reported. One patient was asymptomatic after a 250 mg ingestion; another, who combined 70 mg of amlodipine with an unknown large quantity of a benzodiazepine, developed refractory shock and died.
Human overdoses with any combination of amlodipine and benazepril have not been reported. In scattered reports of human overdoses with benazepril and other ACE inhibitors, there are no reports of death.
Patients should be admitted to hospital and, generally, should be managed in an intensive care setting, with continuous monitoring of cardiac function, blood gases, and blood biochemistry. Emergency supportive measures such as artificial ventilation or cardiac pacing should be instituted if appropriate.
In the event of a potentially life-threatening oral overdose, use induction of vomiting or gastric lavage and/or activated charcoal to remove the drug from the gastrointestinal tract (only if presented within 1 hour after ingestion of amlodipine and benazepril hydrochloride).
Other clinical manifestations of overdose should be managed symptomatically based on modern methods of intensive care.
To obtain up-to-date information about the treatment of overdose, a good resource is your certified Regional Poison-Control Center. Telephone numbers of certified poison-control centers are listed in the Physicians’ Desk Reference (PDR). In managing overdose, consider the possibilities of multiple-drug overdoses, drug-drug interactions, and unusual drug kinetics in your patient.
The most likely effect of overdose with amlodipine and benazepril hydrochloride capsule is vasodilation, with consequent hypotension and tachycardia. Simple repletion of central fluid volume (Trendelenburg positioning, infusion of crystalloids) may be sufficient therapy, but pressor agents (norepinephrine or high-dose dopamine) may be required. With abrupt return of peripheral vascular tone, overdoses of other dihydropyridine calcium channel blockers have sometimes progressed to pulmonary edema, and patients must be monitored for this complication.
Analyses of bodily fluids for concentrations of amlodipine, benazepril, or their metabolites are not widely available. Such analyses are, in any event, not known to be of value in therapy or prognosis.
No data are available to suggest physiologic maneuvers (e.g., maneuvers to change the pH of the urine) that might accelerate elimination of amlodipine, benazepril, or their metabolites. Benazeprilat is only slightly dialyzable; attempted clearance of amlodipine by hemodialysis or hemo-perfusion has not been reported, but amlodipine’s high protein binding makes it unlikely that these interventions will be of value.
Angiotensin II could presumably serve as a specific antagonist-antidote to benazepril, but angiotensin II is essentially unavailable outside of scattered research laboratories.
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