PHARMACOLOGY Nitrate tolerance prevented with hydralazine

It appears that the concomitant use of oral hydralazine can prevent early development of nitrate tolerance in patients with chronic heart failure, say US-based investigators.

Their study involved 28 evaluable patients (including 5 women) with chronic heart failure due to left ventricular systolic dysfunction, who were randomised to receive a continuous infusion of nitroglycerin [glyceryl trinitrate] either alone or with hydralazine 75mg 4 times daily. IV nitroglycerin was administered via an infusion pump for 24 hours to achieve a ~ 30% reduction in mean pulmonary artery wedge pressure or until a maximal dose of 560 flg/min was reached. Haemodynamic parameters were measured at regular intervals during the infusion.

While continuous infusion or frequent use of oral nitrates leads to significant attenuation of nitrate-mediated haemodynamic and anti-ischaemic effects, concomitant use of oral hydralazine resulted in a persistent nitrate-mediated haemodynamic effect on systemic BP, pulmonary artery and pulmonary artery wedge pressures, and left ventricular filling pressures in this study. Gogia H, Mehra A, Parikh S, Raman M. Ajit-Uppal J, et al. Prevention of tolerance to hemodynamic effects of nitrates with concomitant use of hydralazine in patients with chronic heart failure. Journal of the American College of Cardiology 26: 1575-1580, Dec 1995 800414722

0156.2703/9611019-000191$01.00° Adlalnternatlonal Limited 1996. All rlghta reserved

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INPHARMAe 13 Jan 1996