Phenoxybenzamine Capsules

Generic name: phenoxybenzamine hydrochloride
Dosage form: capsule
Drug class:Miscellaneous cardiovascular agents

Medically reviewed by Drugs.com. Last updated on Dec 1, 2020.

Phenoxybenzamine Capsules Description

Each phenoxybenzamine hydrochloride capsule, USP with red cap and body, is imprinted with “Amneal” on cap and “1502” on body, and contains 10 mg of phenoxybenzamine hydrochloride, USP. Inactive ingredients consist of colloidal silicon dioxide, D&C red 33, FD & C red 3, gelatin, iron oxide yellow, lactose monohydrate and sodium lauryl sulfate.

The capsule is imprinted with white pharmaceutical ink which contains butyl alcohol, dehydrated alcohol, isopropyl alcohol, potassium hydroxide, propylene glycol, shellac, strong ammonia solution and titanium dioxide.

Phenoxybenzamine hydrochloride is chemically known as N-(2-Chloroethyl)-N-(1-methyl-2-phenoxyethyl) benzylamine hydrochloride. Its molecular formula is C18H22ClNO·HCl.

The chemical structure is:

Phenoxybenzamine hydrochloride, USP is a white to almost white crystalline powder with a molecular weight of 340.29 g/mol, which melts between 136° and 141°C. It is freely soluble in ethanol (96%) and insoluble in diethyl ether.

Phenoxybenzamine Capsules - Clinical Pharmacology

Phenoxybenzamine hydrochloride is a long-acting, adrenergic, alpha-receptor-blocking agent, which can produce and maintain “chemical sympathectomy” by oral administration. It increases blood flow to the skin, mucosa and abdominal viscera, and lowers both supine and erect blood pressures. It has no effect on the parasympathetic system.

20 percent to 30 percent of orally administered phenoxybenzamine appears to be absorbed in the active form1.

The half-life of orally administered phenoxybenzamine hydrochloride is not known; however, the half-life of intravenously administered phenoxybenzamine hydrochloride is approximately 24 hours. Demonstrable effects with intravenous administration persist for at least 3 to 4 days, and the effects of daily administration are cumulat...