There is marked interindividual variation in hypotensive response to intravenous hydralazine (H). We examined the determinants of response in patients with hypertension. After a single intravenous dose of 0.3 mg/kg H, response was correlated independently (r = 0.8364) with both predrug blood pressure and acetylator index (AI). Intravenous dose ranging studies showed that response also depended on the amount of H in the systemic circulation. Although plasma H levels depend on AI after oral doses, this is not so after intravenous administration. AI must therefore affect response to H by an alternative, presumably nonmetabolic mechanism which, after oral dosing, would add to its effect on H levels. Response to intravenous nitroprusside was not related to AI, perhaps indicating specificity of this effect for H. These data reinforce the potential usefulness of determining AI before giving H to a patient.
ASJC Scopus subject areas
- Pharmacology (medical)