74 Relationship between plasma concentration of nifedipine and pressure control in hypertensive pregnant women

Abstract

Introduction Nifedipine is a calcium channel blocker used in treatment of hypertension in pregnant women. Objective The objective of the present study was to investigate the relation between the plasma concentration of nifedipine and pressure control in hypertensive pregnant women. Methods Twenty-two hypertensive pregnant women taking oral slow-release nifedipine 20 mg every 12 h were evaluated. Serial blood samples were collected at times 0–12 h after administration of the last nifedipine dose during the third trimester of pregnancy. The blood pressure of the patients was measured 4 in 4 hours from the time 0 to 12 h. Concentrations of nifedipine were determined by liquid chromatography–tandem mass spectrometry (LC–MS/MS). The plasma concentration and the mean arterial pressure were reported as mean and standard deviation. Results The maximum fall in the measurement of mean arterial pressure after 4 h (95.4 ± 10.2 mmHg) was observed right after the mean maximum plasma concentration (27.5 ± 10.6 ng/mL) at time of maximum concentration (1.5 ± 0.5 h). As well as the values of mean arterial pressure at time 12 h (102.0 ± 11.1 mmHg) was similar to the values from time zero (106.8 ± 11.5 mmHg). Conclusion The study demonstrate the action of the drug during the dose interval used, as well as its efficacy. Acknowledgement Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq).