Authors: ADA Council on Scientific Affairs.
Title: Antibiotic interference with oral contraceptives.
Journal: J Am Dent Assoc
Date: Jul 2002
Citation: 133(7):880
Category: Endodontic Pharmacology
Evidence-based Ranking: 5
Purpose/Objectives: The purpose of this report is to state the American Dental Association’s current position on antibiotic interference with oral contraceptives. Discussion/Summary: There have been mixed reports on the interaction of various antibiotics on the effectiveness of oral contraceptives. The American Medical Association (May, 2002) concluded that women should be informed of the possible interaction, because such an interaction could not be completely discounted and could not be predicted. This conclusion was based on documented interaction between rifampin (an antibiotic used to treat tuberculosis and staphylococcal infections) and oral contraceptives, anecdotal case reports suggesting an oral contraceptive failure associated with other antibiotics, and a plausible hypothesis of a mechanism of action. It is thought that rifampin stimulates liver enzymes which can have an effect on the oral contraceptive and that other antibiotics may alter levels of ethinyl estradiol, the principal active ingredient in oral steroid contraceptives. A recently published report (Hersh, JADA, 1999) identified some antibiotics commonly used in dentistry (amoxicillin, ampicillin, metronidazole and tetracycline) as drugs that may decrease the effectiveness of oral contraceptives.

Therefore, it is the opinion of the ADA Council on Scientific Affairs that, considering the possible consequences of an unwanted pregnancy, when prescribing antibiotics to a patient using oral contraceptives, the dentist should do the following: 1. Advise the patient of the potential risk of the antibiotic’s reducing the effectiveness of the oral contraceptive; 2. Recommend that the patient discuss with her physician the use of an additional non-hormonal means of contraception; 3. Advise the patient to maintain compliance with oral contraceptives when concurrently using antibiotics.