[Dose-dependent side effects of acetylsalicylic acid therapy. Results of a prospective randomized clinical study in patients with peripheral arterial occlusive disease].

METHODS

In 359 patients with peripheral arterial occlusive disease who had undergone percutaneous transluminal angioplasty (PTA), a randomized double-blind, controlled clinical study was done to investigate the tolerability of acetyl salicylic acid (ASA) given for reocclusion prophylaxis. A comparison was made between a conventional daily dose of 900 mg ASA and a dose of 50 mg ASA.

RESULTS

Within an observation period of one year following PTA, 35 patients (20%) in the 900 mg group, and 32 patients (17%) in the 50 mg group left the trial because of side effects (p = NS). Under the higher dose, however, severe gastrointestinal side effects (ulcer, haemorrhagic gastritis requiring transfusion) were significantly more common (nine patients delta 5.1% vs two patients delta 1.1%, respectively; p = 0.03). Overall, 107 patients (30%) reported subjective side effects such as upper abdominal pain, a sensation of fullness or nausea during the course of the trial. 62 of these patients were from the 900 mg group (35%) as compared with 45 patients (24%) in the 50 mg group (p = 0.02). Self-scoring of epigastric pain on the basis of a visual analogue scale revealed a score of 1.3 (95% confidence interval 0.9 to 1.6) in the 900 mg group and 0.8 (95% confidence interval 0.6 to 1.0) in the 50 mg group. The subjective pain intensity showed a uniform time course for all three types of symptom, with a maximum after three months.

CONCLUSIONS

Our results confirm the superior tolerability of the lower dose, in particular in elderly patients. For long-term treatment, the smallest possible effective dose should be chosen.