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Phenoxybenzamine

Also sold as: Dibenzyline

Adrenergic alpha-AntagonistsPrescription OnlyGeneric Available

Related Medications

Important: Only drugs listed as "Exact Equivalents" (FDA AB-rated) are confirmed interchangeable. All other listings are for informational reference only and do NOT indicate that drugs can be substituted without a physician's explicit guidance.
Same Pharmacologic Class

These drugs share a pharmacologic classification but are NOT interchangeable. Listing here does not imply clinical equivalence. A physician must evaluate each drug individually for the patient's specific condition.

Classification: Adrenergic alpha-Antagonists (source: RxClass/NLM)

Insurance Coverage User-Reported

No community coverage data yet for phenoxybenzamine.

Coverage data submission coming soon.

Drug Information

Indications & Uses

INDICATION AND USAGE Phenoxybenzamine hydrochloride capsules are indicated in the treatment of pheochromocytoma, to control episodes of hypertension and sweating. If tachycardia is excessive, it may be necessary to use a beta -blocking agent concomitantly.

Dosage & Administration

DOSAGE AND ADMINISTRATION The dosage should be adjusted to fit the needs of each patient. Small initial doses should be slowly increased until the desired effect is obtained or the side effects from blockade become troublesome. After each increase, the patient should be observed on that level before instituting another increase . The dosage should be carried to a point where symptomatic relief and/or objective improvement are obtained, but not so high that the side effects from blockade become troublesome. Initially, 10 mg of phenoxybenzamine hydrochloride twice a day. Dosage should be increased every other day, usually to 20 mg to 40 mg 2 or 3 times a day, until an optimal dosage is obtained, as judged by blood pressure control. Long-term use of phenoxybenzamine is not recommended (see PRECAUTIONS - Carcinogenesis and Mutagenesis ).

Warnings & Precautions

WARNING Phenoxybenzamine hydrochloride-induced alpha -adrenergic blockade leaves beta -adrenergic receptors unopposed. Compounds that stimulate both types of receptors may, therefore, produce an exaggerated hypotensive response and tachycardia.

Side Effects (Adverse Reactions)

ADVERSE REACTIONS The following adverse reactions have been observed, but there are insufficient data to support an estimate of their frequency. Autonomic Nervous System*: Postural hypotension, tachycardia, inhibition of ejaculation, nasal congestion, miosis. *These so-called “side effects” are actually evidence of adrenergic blockade and vary according to the degree of blockade. Miscellaneous: Gastrointestinal irritation, drowsiness, fatigue. To report SUSPECTED ADVERSE REACTIONS, contact Amneal Pharmaceuticals at 1-877-835-5472 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

Drug Interactions

Drug Interactions 2 – Phenoxybenzamine hydrochloride may interact with compounds that stimulate both alpha- and beta- adrenergic receptors (i.e. epinephrine) to produce an exaggerated hypotensive response and tachycardia (see WARNING ). Phenoxybenzamine hydrochloride blocks hyperthermia production by levarterenol, and blocks hypothermia production by reserpine.

Contraindications

CONTRAINDICATIONS Conditions where a fall in blood pressure may be undesirable; hypersensitivity to the phenoxybenzamine hydrochloride capsules, or any of its components.

Verify with Primary Sources

Always verify clinical information with authoritative sources.

DailyMed (NLM/NIH)FDA-approved drug labeling↗FDA Orange BookTherapeutic equivalence data↗RxNorm (NLM/NIH)Drug nomenclature & relationships↗