Drotaverine (INN, also known as drotaverin) is an antispasmodic drug, structurally related to papaverine. Drotaverine is a selective inhibitor of phosphodiesterase 4, and has no anticholinergic effects. Drotaverine has been shown to possess dose-dependant analgesic effects in animal models. One small study has shown drotaverine to be eliminated mainly non-renally. (en)
Drotaverine inhibits phosphodiesterases hydrolysing cAMP, thereby increasing cAMP concentration, decreasing Ca uptake of the cells and changing the distribution of calcium among the cells. It may also have minor allosteric calcium channel blocking properties. (en)