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Does anyone know if metronidazole decreases the effectiveness of oral contraceptives? I'm getting a lot of contradictory information, thank you!
metronidazole and OCPs
- Thread starter Messerschmitts
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My understanding is that rifampin is the only abx known to actually decrease effectiveness. I was told this by a Family Planning attending at Magee.
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The pubmed search "metronidazole contraceptive" may help you, or some more sophisticated variation.
The most interesting hit I got from that was this:
http://www.ncbi.nlm.nih.gov/pubmed/12063491
1: J Am Acad Dermatol. 2002 Jun;46(6):917-23. Links
Oral contraceptive efficacy and antibiotic interaction: a myth debunked.
Archer JS, Archer DF.
Department of Obstetrics and Gynecology, Medical University of South Carolina, Charleston 29425, USA.
The purpose of this study was to review the pharmacokinetic and clinical literature regarding the efficacy of oral contraceptives when used concomitantly with antibiotic therapy. Relevant literature was identified by searching MEDLINE and EMBASE. Other sources were located by consulting the bibliographies of the material collected from MEDLINE and EMBASE. Pharmacokinetic evidence demonstrates that plasma levels of oral contraceptive steroids are unchanged with the concomitant administration of antibiotics, including ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline. However, reduced steroid levels have been reported in women taking rifampin with oral contraceptives. Clinical reports of contraceptive failure with antibiotic use are retrospective, have multiple potential biases, and are not supported by pharmacokinetic data. Available scientific and pharmacokinetic data do not support the hypothesis that antibiotics (with the exception of rifampin) lower the contraceptive efficacy of oral contraceptives.
PMID: 12063491 [PubMed - indexed for MEDLINE]
The most interesting hit I got from that was this:
http://www.ncbi.nlm.nih.gov/pubmed/12063491
1: J Am Acad Dermatol. 2002 Jun;46(6):917-23. Links
Oral contraceptive efficacy and antibiotic interaction: a myth debunked.
Archer JS, Archer DF.
Department of Obstetrics and Gynecology, Medical University of South Carolina, Charleston 29425, USA.
The purpose of this study was to review the pharmacokinetic and clinical literature regarding the efficacy of oral contraceptives when used concomitantly with antibiotic therapy. Relevant literature was identified by searching MEDLINE and EMBASE. Other sources were located by consulting the bibliographies of the material collected from MEDLINE and EMBASE. Pharmacokinetic evidence demonstrates that plasma levels of oral contraceptive steroids are unchanged with the concomitant administration of antibiotics, including ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline. However, reduced steroid levels have been reported in women taking rifampin with oral contraceptives. Clinical reports of contraceptive failure with antibiotic use are retrospective, have multiple potential biases, and are not supported by pharmacokinetic data. Available scientific and pharmacokinetic data do not support the hypothesis that antibiotics (with the exception of rifampin) lower the contraceptive efficacy of oral contraceptives.
PMID: 12063491 [PubMed - indexed for MEDLINE]
