The efficacy of a once daily transdermally applied
nitroglycerin system and of sustained release
nitroglycerin capsules was assessed by ergometer stress testing in 12 patients with
stable angina pectoris in a double-blind crossover study. In the morning the patients received transdermally applied
nitroglycerin (
TDS) which delivered 5.0 mg
nitroglycerin in 24 hours together with a placebo
capsule, respectively 1
nitroglycerin (NTR)
capsule of 2.5 mg together with a plaster placebo. In the evening the first treatment group received 2 placebo capsules, and the second group 1 NTR
capsule and 1 placebo
capsule. Each period lasted 14 days. The patients performed a pre-medication ergometer stress test and repeated the test on the first and 14th day of each treatment period, 1 and 24 hours after medication. At the end of the second period all patients continued in an open study with
TDS once a day for a further three months. Minor degrees of ST-segment depression, and in fewer patients, were observed at comparable workloads in the treatment tests compared with the pre-medication tests. The improvement after
TDS on the first and last day of each period, 1 and 24 hours after medication, was significant and more marked than with NTR. The latter did not reach significance. Furthermore, increase of work capacity and elevation of angina threshold was greater with
TDS than with NTR. Similar results were found at the end of the open study after 3 months' treatment with
TDS. No development of tolerance was observed.