Quality Resource Guide l Antibiotic Use in Dentistry 4th Edition 5 www.metdental.com Table 2 - Clinically significant drug interactions involving antibiotics used in dentistry (modified from reference 18) Primary Drug Action Interaction (and Effect) Alcohol ...metabolism decreased by... Metronidazole (severe nausea, vomiting) Benzodiazepines ...enhanced by... Erythromycin, clarithromycin (increased CNS depression) Carbamazepine ...enhanced by... Erythromycin, clarithromycin (increase carbamazepine toxicity) Coumarins (including warfarin) ...enhanced by... Erythromycin, clarithromycin, metronidazole, penicillins, tetracyclines (increased risk of bleeding) Digoxin ...enhanced by... Erythromycin, clarithromycin (increased toxicity of digoxin, including cardiac arrhythmias) Lidocaine ...enhanced by... Erythromycin, clarithromycin (increased toxicity of lidocaine, CNS depression) Penicillins ...antagonized by... Coumarin, phenytoin, griseofulvin (reduced efficacy against infection) Statins ...enhanced by... Erythromycin, clarithromycin (increased statin toxicity, e.g., rhabdomyolysis) Tetracyclines ...antagonized by... Antacids, iron (reduced absorption of tetracyclines) Tetracyclines ...antagonizes... Penicillin (reduced efficacy against infection) Theophylline ...potentiated by... Erythromycin, clarithromycin (increase toxicity of theophylline, possible cardiac arrhythmias) Less significant drug interactions are also possible - the clinician is urged to consult the complete prescribing information for all drugs prescribed. For medically compromised patients with systemic disease that could impact drug metabolism and/or excretion, consultation with the patient’s physician is recommended.