Local transdermal glyceryl trinitrate has an antiinflammatory action on thrombophlebitis induced by sclerosis of leg varicose veins.
To test the antiinflammatory and analgesic effects of transdermal glyceryl trinitrate (GTN) the authors carried out a double-blind, randomized, controlled clinical study in 21 patients with mild to moderate leg varicose veins who underwent vein sclerotherapy in both legs. GTN or placebo ointment was applied in a blinded protocol along the surface of the sclerosed vein every eight hours until disappearance of inflammation signs. The varicose vein in one leg was treated with GTN and compared with placebo for the vein of the other leg used as control of thrombophlebitis (TP) signs. Fifteen minutes after first application inflammation signs were observed in all cases. The intensity of inflammation signs was assessed as 26% (10.4 +/- 4.1) in GTN-treated veins and as 61.5% (24.6 +/- 6.3) (P < 0.001) in the placebo-treated veins. One hour later only 63% of cases in the GTN group and all cases in the placebo group showed signs of TP (P < 0.001). The reduction in the intensity of signs at this time was 7.7 +/- 3.9 in the GTN group and 19.7 +/- 6.3 in the placebo group (P < 0.001). All veins in the GTN group were free of signs of TP in less than forty-eight hours. In the placebo group, 45% of veins required more than forty-eight hours for complete disappearance of signs of TP (P < 0.001). The authors conclude that GTN has an antiinflammatory effect in TP induced by sclerotherapy. This action may be related to the nitric oxide released from GTN, through a direct action on the vein and the surrounding inflamed tissue.