PREVENTION OF NITROGLYCERIN TOLERANCE WITH DIURETICS

Tolerance to prolonged nitroglycerin (NTG) may be due to drug-induced intravascular expansion, To test the hypothesis that concomitant diure tics may reduce volume expansion and thus prevent NTG tolerance, we st udied 23 healthy volunteers randomized to hydrochlorthiazide or placeb o before and during 74-hour continuous NTG exposure, Venodilator respo nse to NTG was tested serially with venous forearm plethysmography, In the preNTG patch phase venodilator response was similar in both the p lacebo and diuretic groups, Venodilator capacity was compared after '' acute'' (2-hour) and ''chronic'' (74-hour) NTG exposure with NTG patch es, Attenuation to NTG was seen in the placebo group, but NTG venodila tor activity was fully maintained in the diuretic group, These data su ggest that diuretics may be helpful in the prevention of NTG tolerance .