ANTIPYRINE, COUMARIN AND GLIPIZIDE AFFECT N-ACETYLATION MEASURED BY CAFFEINE TEST

The effect of various treatments on acetylation status measured by caf feine metabolites was investigated in 17 subjects with non-insulin dep endent diabetes mellitus (NIDDM). The test drugs, caffeine (200 mg), a ntipyrine (20 mg/kg) and coumarin (5 mg), were given simultaneously, a nd urinary ino-6-formyl-amino-3-methyluracil/1-methylxanthine (AFMU/1X ) molar ratio was measured before and after 8 weeks of therapy. The ur inary AFMU/1X molar ratio decreased(p< 0.05) after 8 weeks of therapy with glipizide (2.5 mg), but remained unaltered in those treated with placebo or those who self-monitored blood glucose (SMBG) by glucometer . Antipyrine and coumarin decreased (p < 0.05) the AFMU/1X molar ratio both in diabetics and healthy volunteers. Our data demonstrate that g lipizide, antipyrine and coumarin may interfere with the classificatio n of acetylator status measured by caffeine metabolites.