Proxibarbital (Ipronal) is a barbiturate derivative synthesized in 1956. It has anti-anxiety properties and is, in contrast to most barbiturates, almost without hypnotic action. It was also used in the treatment of migraine headaches in a similar manner to butalbital. Valofane isomerises to Proxibarbal in vivo. References Barbiturates Antimigraine drugs Allyl compounds GABAA receptor positive allosteric modulators