ROUTE AND RATE OF HYDRALLAZINE ADMINISTRATION AS DETERMINANTS TO ITS HYPOTENSIVE EFFECT IN RABBITS

SUMMARY 1. The cardiovascular responses to varying doses of hydralazine were studied in renal hypertensive rabbits. 2. The depressor effect of hydralazine was independent of the rate of its i.v. administration (bolus v. a 15 min constant infusion). 3. Intraperitoneally administered hydralazine was significantly less active than equimolar i.v. doses, and the relative potency (i.p. v. i.v.) did not increase with increasing doses. 4. In spite of inferential evidence to the contrary, we did not find any pharmacodynamic support for non-linear processes being involved in metabolism of hydralazine.