Clinical pharmacokinetics of hydralazine

Hydralazine is one of the most frequently prescribed drugs for the treatment of moderate to severe hypertension. In addition, it is being used increasingly for the treatment of congestive heart failure when more traditional approaches fail. Although hydralazine has been in clinical use for 30 years, there is insufficient information concerning dose-blood concentration and blood concentration-response relationships to formulate rational approaches for dosage individualisation. This paucity of data is primarily due to the fact that many previous methods for measurement of hydralazine in plasma were non-selective and measured circulating, inactive metabolites. Recently, more selective procedures have been developed and are being applied to the study of the pharmacokinetic behaviour of hydralazine in man.