Warning against using erythromycin (even orally) while using protease inhibitors or certain other drugs.
A study of medical records found that combining the antibiotic erythromycin with strong inhibitors of the liver enzyme CYP3A increased the risk of sudden death from cardiac causes--probably by abnormally raising the blood levels of erythromycin.
D000284:Administration, Oral; D000900:Anti-Bacterial Agents / Q000008:administration & dosage; D001189:Aryl Hydrocarbon Hydroxylases / Q000037:antagonists & inhibitors; D000075202:Contraindications; D051544:Cytochrome P-450 CYP3A; D004347:Drug Interactions; D004917:Erythromycin / Q000008:administration & dosage; D015658:HIV Infections / Q000188:drug therapy*; D017320:HIV Protease Inhibitors / Q000008:administration & dosage*; D006801:Humans; D010089:Oxidoreductases, N-Demethylating / Q000037:antagonists & inhibitors
D000900:Anti-Bacterial Agents; D017320:HIV Protease Inhibitors; D004917:Erythromycin; D001189:Aryl Hydrocarbon Hydroxylases; D051544:Cytochrome P-450 CYP3A; D010089:Oxidoreductases, N-Demethylating