Interaction of hydralazine with barbiturates.

Barbiturates given together with hydralazine significantly change the hypotensive effect of the latter. The final effect depends on the kind of barbiturate, time of its administration, and initial functional state of the circulatory system. Hydralazine given together with barbiturates significantly prolongs their hypnotic action and shortens the latency of that action. In the case of a short-acting barbiturate, hexobarbital, this effect appears in normotensive rats only if the barbiturate is given 60 min prior to hydralazine administration.