Feprosidnine, sold under the brand name Sydnophen, is a stimulant drug which was developed in the USSR in the 1970s.

Sydnophen has multiple mechanisms of action, the relative importance of which has not been clearly established.

Effects on the body include reversible monoamine oxidase inhibition, cholinergic,[3] adrenergic,[4] opioid[5] and nitric oxide donating[6] actions, all of which may contribute to its pharmacological effects to some extent.

The amphetamine [300-62-9] (2) is then added and this is allowed to react overnight to give N-(1-phenyl-2-propylamine)-acetonitrile (3).

Nitrosylation of the amino group by in situ creation of nitrous acid from hydrochloric acid and sodium nitrite results in a 51.5% yield of feprosidnine based on the initial weight of the amine (4).