The effects of glyceryl trinitrate and nicotinic acid ointments during cold exposure.

The aim of the present experimental study was to examine the effects of local application of glyceryl trinitrate and nicotinic acid on the cold-provoked haemodynamic responses, pain and hand dexterity. Ten young healthy volunteers participated in this randomized, cross-over study with three phases at least two days apart. Five cm of 2% glyceryl trinitrate ointment, 10% nicotinic acid ointment or placebo ointment was applied on the back of each subject's both hands 15 min. before the 7 min. cold exposure. Blood pressure and heart rate were measured prior to, during and after the cold exposure. In addition, the effect of cold on hand dexterity was evaluated by the Purdue pegboard test and the subjects assessed the pain in their hands during the cold exposure. Pretreatment with glyceryl trinitrate ointment counteracted the cold-induced haemodynamic response, as evidenced by a significantly (P < 0.05) smaller mean increase in the systolic blood pressure from the baseline compared with placebo. In contrast, the cold-induced increase in the systolic blood pressure observed after pretreatment with nicotinic acid ointment did not differ from placebo. Both glyceryl trinitrate and nicotinic acid alleviated the cold-induced pain, but neither of them prevented the deterioration of hand dexterity. In conclusion, the haemodynamic response provoked by a brief cold exposure could to some extent be counteracted by pretreatment with glyceryl trinitrate ointment, but not with nicotinic acid ointment, compared with placebo.