The long-term safety and tolerability of transdermal glyceryl trinitrate, when used with a patch-free interval in patients with stable angina.

The safety and tolerability of intermittent (16 hours on/8 hours off) nitrate patch therapy (0.2, 0.4 or 0.6 mg/hr: dose adjusted as required) was studied for a median duration of 356 days in 106 patients (mean age 60.9 +/- 8.6 years) with angina pectoris. Most patients (82%) were on existing beta-blocker and/or calcium antagonist therapy. Safety, tolerability and efficacy data were obtained by means of patient diary cards and regular clinic visits. Almost 90 treatment years revealed no significant or serious adverse events, and there were no changes in haematology or biochemistry associated with intermittent nitrate patch therapy. The most frequently reported side-effects were headache, skin reactions and dizziness (53%, 20% and 8% of patients respectively). Treatment resulted in a sustained reduction in the frequency and severity of angina attacks, reduced sublingual GTN consumption, an improvement in general wellbeing and a rise in the proportion of patients in whom angina was controlled.