Hydralazine Dose is affected by its pharmacokinetics. Hydralazine is well absorbed orally, and is subjected to first pass metabolism in liver. The chief metabolic pathway is acetylation which exhibits a bimodal distribution in the population there are slow and fast acetylators. Bioavailability is higher in slow acetylators, but these patients are more prone to develop the lupus syndrome.
Hydralazine dose is also adjusted as it is completely metabolized both in liver and plasma; the metabolites are excreted in urine, t½ 1-2 hours. However, hypotensive effect lasts longer (12 hours), probably because of its persistence in the vessel wall.
Hydralazine Dose is 25-50 mg one daily or in divided doses.
Commercial preparation: NEPRESOL 25 mg tab.