Drotaverine

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.

A small 2003 study found drotaverine to be nearly 80% effective in treating renal colic. It has also been used to accelerate labor.