Serum magnesium levels in patients after myocardial infarction or unstable angina treated with nitrites and calcium antagonists.

A rise of serum Mg levels was observed in patients at 3 and 6 months after acute myocardial infarction, irrespective of therapeutic regimen. In unstable angina follow-up, serum Mg levels remained stable, but below normal values (normal mean values = 2.1 +/- SD 0.4 mg%). A significant difference between mean Mg levels at 6 months was noted in patients with unstable angina treated with calcium antagonists and nitrites as well as in patients treated only with nitrites (p less than 0.02).