Papaverine (Latin papaver, “poppy”) is an opium alkaloid antispasmodic drug, used primarily in the treatment of visceral spasm and vasospasm (especially those involving the intestines, heart, or brain), and occasionally in the treatment of erectile dysfunction.
While it is found in the opium poppy, papaverine differs in both structure and pharmacological action from the analgesic morphine-like compounds.
Papaverine is found as a contaminant in some heroin and can be used by forensic laboratories in heroin profiling to identify its source.
The metabolites can also be found in the urine of heroin users, allowing street heroin to be distinguished from pharmaceutical diacetylmorphine.
In the US Papaverine is a Rx Only drug.