Letters to the Editor: Letter to the Editor
To the Editor
Our institutions, along with many others across the country, have revised protocols to address potential issues for women on oral contraceptives who have received sugammadex in the perioperative period. According to the package insert from Merck & Co, Inc, “5.6 Due to the administration of Bridion, certain drugs, including hormonal contraceptives, could become less effective due to a lowering of the (free) plasma concentrations.” The insert also states, “7.3 In vitro binding studies indicate that Bridion may bind to progestogen, thereby decreasing progestogen exposure. Therefore, the administration of a bolus dose of Bridion is considered to be equivalent to missing dose(s) of oral contraceptives containing an estrogen or progestogen. If an oral contraceptive is taken on the same day that Bridion is administered, the patient must use an additional, non-hormonal contraceptive method or back-up method of contraception for the next 7 days.” Due to these warnings, it is our understanding that many anesthesiologists and their institutions have gone to great lengths to notify patients of this potential risk by providing both counseling and additional discharge paperwork suggesting alternative contraceptive use for this patient subset.
Interestingly, a similar potential risk exists with the administration of common perioperative antibiotics. The package insert for a common oral contraceptive ORTHO-NOVUM tablets (norethindrone/ethinyl estradiol) states, “Contraceptive effectiveness may be reduced when hormonal contraceptives are coadministered with antibiotics, anticonvulsants, and other drugs that increase the metabolism of contraceptive steroids.” While some of the implicated medications include antibiotics that are frequently administered in the perioperative period, there has been a previous lack of discussion and counseling regarding those potential risks. Although studies have not been definitively conclusive, many antibiotics are believed to decrease oral contraceptive efficacy, including cephalosporins, tetracyclines, antifungals, penicillins, macrolides, metronidazole, and sulphonamides.1 Particular individuals have shown more susceptibility to fluctuating plasma hormonal levels in the face of antibiotic administration.2 Some antibiotics cause interruption of the enterohepatic cycling of ethinylestradiol, leading to inhibition of hydrolysis of the conjugated hormone with subsequent increased fecal loss and ultimately lower circulating levels of ethinylestradiol. Others promote induction of cytochrome P450 hepatic microsomal enzymes, increasing metabolism of both the estrogen and progesterone component. We find it interesting that a new product such as sugammadex with only in vitro-binding studies warrants such attention and change in practice, but previous warning of interactions between oral contraceptives and antibiotics has to this date been relatively dismissed.
Perhaps we need more definitive data to support changing our system. Or perhaps a revision of the anesthetic consent should contain a general statement such as, “You may receive medications during your anesthetic that could interfere with the effectiveness of oral contraceptives. If you are using oral contraceptives, consider alternative methods of birth control for 7 days following your anesthetic.” This disclosure would cover potential interactions with sugammadex, antibiotics, and other medications.
David M. Corda, MDDepartment of AnesthesiologyUniversity of Florida College of MedicineGainesville, Floridadcorda@anest.ufl.edu
Christopher B. Robards, MDDepartment of Anesthesiology and Perioperative MedicineMayo Clinic FloridaJacksonville, Florida
1. Bainton R. Interaction between antibiotic therapy and contraceptive medication. Oral Surg Oral Med Oral Pathol. 1986;61:453–455.
2. Dickinson BD, Altman RD, Nielsen NH, Sterling ML; Council on Scientific Affairs; American Medical Association. Drug interactions between oral contraceptives and antibiotics. Obstet Gynecol. 2001;98:853–860.