It was also the first alpha blocker to be used for treatment of benign prostatic hyperplasia,[2] although it is currently seldom used for that indication due to unfavourable side effects.

Phenoxybenzamine has long been known to block ejaculation without affecting semen quality or ability to achieve orgasm, which could make it an effective male contraceptive.

[4][5][6] A dose of 20 mg/day results in aspermia due to reversible paralyzing effects on the vas deferens, ampulla, and ejaculatory ducts.

Based on known information about the structures of these receptors, it likely involves attack by the cysteine at position 3.36 in transmembrane helix 3 to form a stable linkage.

Its only current clinical use is in preparing patients with pheochromocytoma for surgery; its irreversible antagonism and the resultant depression in the maximum of the agonist dose-response curve are desirable in a situation where surgical manipulation of the tumour may release a large bolus of pressor amine into the circulation.

[9][10][11][12] Due to its 5-HT2A receptor antagonism, phenoxybenzamine is useful in the treatment of carcinoid tumor, a neoplasm that secretes large amounts of serotonin and causes diarrhea, bronchoconstriction, and flushing.