Papaverine is a opium alkaloid antispasmodic drug, used primarily in the treatment of visceral spasms and vasospasms (especially those involving the intestines, heart, or brain), occasionally in the treatment of erectile dysfunction and acute mesenteric ischemia.
It is used as an erectile dysfunction drug, alone or sometimes in combination. Papaverine, when injected in penile tissue, causes direct smooth muscle relaxation and consequent filling of the corpus cavernosum with blood resulting in erection.
Off-label it is a prophylaxis (preventative) for migraine headaches. It is not a first line drug such as a few beta blockers, calcium channel blockers, tricyclic antidepressants, and some anticonvulsants such as divalproex, but rather when these first line drugs and secondary drugs such as SSRIs, angiotensin II receptor antagonists, etc. fail in the prophylaxis of migraines, have intolerable side effects or are contraindicated.
