[Anti-anginal efficacy of oral nitroglycerin. A clinical double-blind study with dose-effect relationships]

Nitroglycerin, bound to polymerized cellulose (Nitroglin) was administered orally in single doses of 2.6 mg, 6.5 mg, 10 mg and 20 mg (randomized sequence) on four different days to 12 patients with angina due to coronary heart disease. This was done within the framework of a placebo-controlled double-blind study with intra-individual cross-over to assess dose-related reduction of the ischaemia reaction in the exercise ECG. The ischaemia reaction (sum of ST segment depressions) 30 min after a placebo was 10.4 +/- 4.6 mm; after 2.6 mg nitroglycerin it was 8.0 +/- 4.3 mm (-23%, not significant); after 6.5 mg it was 6.4 +/- 3.4 mm (-38%, P less than 0.01), after 10 mg it was 4.7 +/- 2.9 mm (-55%, P less than 0.001), and after 20 mg 2.7 +/- 1.9 mm (-74%, P less than 0.0001). The dose-related effect of nitroglycerin was still demonstrable to the same extent three hours after intake. After 20 mg a reduction in ischaemia reaction by 55% compared with the placebo effect was still present 6 hours later (P less than 0.01). The arterial blood pressure on lying and standing as well as the heart rate on lying, standing and on exercise did not change significantly, regardless of dose. Taken by mouth nitroglycerin was well tolerated and had a dose-related anti-anginal effect. After single doses of 10-20 mg the anti-ischaemic effect was shown to persist for several hours.