Benazepril overdosage
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overdosage
Single oral doses of 3 g/kg benazepril were associated with significant lethality in mice. Rats, however, tolerated single oral doses of up to 6 g/kg. Reduced activity was seen at 1 g/kg in mice and at 5 g/kg in rats. Human overdoses of benazepril have not been reported, but the most common manifestation of human benazepril overdosage is likely to be hypotension, which can be associated with electrolyte disturbances and renal failure.
Laboratory determinations of serum levels of benazepril and its metabolites are not widely available, and such determinations have, in any event, no established role in the management of benazepril overdose.
No data are available to suggest physiological maneuvers (e.g., maneuvers to change the pH of the urine) that might accelerate elimination of benazepril and its metabolites. Benazepril is only slightly dialyzable, but dialysis might be considered in overdosed patients with severely impaired renal function (see WARNINGS).
Angiotensin II could presumably serve as a specific antagonist-antidote in the setting of benazepril overdose, but angiotensin II is essentially unavailable outside of scattered research facilities. Because the hypotensive effect of benazepril is achieved through vasodilation and effective hypovolemia, it is reasonable to treat benazepril overdose by infusion of normal saline solution.
If ingestion is recent, activated charcoal should be considered. Gastric decontamination (e.g., vomiting, gastric lavage) may be considered in individual cases, in the early period after ingestion.
Patients should be closely monitored for blood pressure and clinical symptoms. Supportive management should be employed to ensure adequate hydration and to maintain systemic blood pressure.
In the case of marked hypotension, physiological saline solution should be administered intravenously; depending on the clinical situation the use of vasopressors (e.g., catecholamines i.v.) may be considered.[1]
References
Adapted from the FDA Package Insert.