Caverject Mechanism of Action

Pharmacotherapeutic group: Drugs used in erectile dysfunction. ATC code: G04B E01.
Pharmacology: Pharmacodynamics: Alprostadil is present in various mammalian tissues and fluids. It has a diverse pharmacologic profile, among which some of its more important effects are vasodilation, inhibition of platelet aggregation, inhibition of gastric secretion, and stimulation of intestinal and uterine smooth muscle. The pharmacologic effect of alprostadil in the treatment of erectile dysfunction is presumed to be mediated by inhibition of alpha₁- adrenergic activity in penile tissue and by its relaxing effect on cavernosal smooth muscle.
Pharmacokinetics: Following intracavernous injection of 20 micrograms of alprostadil, mean peripheral levels of alprostadil at 30 and 60 minutes after injection are not significantly greater than baseline levels of endogenous PGE1. Peripheral levels of the major circulating metabolite, 15-oxo-13,14-dihydro-PGE1, increase to reach a peak 30 minutes after injection and return to pre-dose levels by 60 minutes after injection. Any alprostadil entering the systemic circulation from the corpus cavernosum will be rapidly metabolized. Following intravenous administration, approximately 80% of the circulating alprostadil is metabolized in one pass through the lungs, primarily by beta- and omega-oxidation. The metabolites are excreted primarily by the kidney and excretion is essentially complete within 24 hours. There is no evidence of tissue retention of alprostadil or its metabolites following intravenous administration.
Toxicology: Preclinical Safety Data: No relevant information additional to that already contained in this monograph.