Search

Background: Rifamycin antibiotics are commonly used for treatment of tuberculosis, but may reduce the effectiveness of hormonal contraception (HC)., Objectives: To determine whether interactions between rifamycins and HC result in decreased effectiveness or increased toxicity of either therapy., Search Strategy: We searched MEDLINE, Embase, Cochrane and clinicaltrials.gov through May 2017., Selection Criteria: We included trials, cohort, and case-control studies addressing pregnancy rates, pharmacodynamics or pharmacokinetic (PK) outcomes when HC and rifamycins were administered together versus apart. Of 7291 original records identified, 11 met inclusion criteria after independent review by two authors., Data Collection and Analysis: Two authors independently abstracted study details and assessed study quality using the United States Preventive Services Task Force grading system. Findings are reported descriptively., Main Results: Studies only addressed combined oral contraceptives (COCs) and none reported pregnancy rates. Quality ranged from good to poor. Rifampin increased the frequency of ovulation in two of four studies, and reduced estrogen and/or progestin exposure in five studies. Rifabutin led to smaller PK changes than rifampin in two studies. In one study each, rifaximin and rifalazil did not alter hormone PK., Conclusions: No studies evaluated pregnancy risk or non-oral HCs. PK and ovulation outcomes support a clinically concerning drug interaction between COCs and rifampin, and to a lesser extent rifabutin. Data are limited for other rifamycins., Tweetable Abstract: Rifampin and rifabutin reduce systemic exposure of oral contraceptives, but no studies have evaluated pregnancy risk., (© 2017 Royal College of Obstetricians and Gynaecologists.)

Objective: To evaluate from the literature whether combined hormonal contraception (CHC), including combined oral contraception pills (COCs), transdermal patch, vaginal ring or combined injectables, have different effectiveness or failure rates by body weight or body mass index (BMI)., Study Design: We searched PubMed and the Cochrane Library databases for all articles in all languages published between inception and February 2016, for evidence relevant to body weight or BMI, CHC use and contraceptive effectiveness. The quality of each individual study was assessed using the system for evaluating evidence developed by the United States Preventive Services Task Force., Results: From 2874 articles, we identified 15 reports for inclusion, all of fair to poor quality. Fourteen studies measured the association of obesity status and contraceptive failure among COC users. Three fair quality and one poor quality study reported increased COC failure among a heterogeneous population of overweight and obese women compared with normal weight women, while eight fair quality and two poor quality studies did not find an association. Two fair quality studies reported on contraceptive transdermal patches. One pooled analysis described a higher proportion of pregnancies among women using the patch who weighed ≥90 kg; another secondary analysis suggested BMI>30 was associated with increased failure. No studies directly compared contraceptive effectiveness using the combined vaginal ring or combined injectable., Conclusion: Current available evidence addressing the risk of CHC failure in obese compared to normal weight women is limited to fair and poor quality studies. Studies of COCs show mixed results, though absolute differences in COC failure by body weight and BMI are small. Based on limited evidence, it appears that increasing body weight and BMI may contribute to decreasing contraceptive patch effectiveness., (Copyright © 2017. Published by Elsevier Inc.)

Context: Combined hormonal contraceptive (CHC) use may modify the risk of cardiovascular events in obese [body mass index (BMI) ≥30kg/m 2 ] women., Objective: The objective was to evaluate from the literature whether CHC use modifies the risk of acute myocardial infarction (AMI), stroke, cerebral venous thrombosis (CVT) and venous thromboembolism (VTE) in obese women and to evaluate evidence for a dose-response relationship between BMI and VTE., Methods: We searched PubMed for all articles published between database inception and February 2016 providing direct evidence on BMI, CHCs, and cardiovascular outcomes. We also searched for indirect evidence related to a dose-response relationship between BMI and risk of VTE in the general population, as these data were lacking for CHC users. The quality of each individual study was assessed using the system for grading evidence developed by the United States Preventive Services Task Force., Results: The direct evidence search yielded 3 pooled analyses, 11 case-control studies and 1 cohort study. There was conflicting evidence about the risk of AMI or stroke among obese combined oral contraceptive (COC) users compared to obese nonusers, with one study finding no increased risk for AMI or stroke for COC users overall or stratified by BMI. A second study found significantly increased risk of AMI and stroke for COC users, with the highest risk estimates for high-BMI COC users. A single study suggested that obese COC users may be at higher risk for CVT compared with normal-weight nonusers. For VTE, obese COC users consistently had a risk that was 5 to 8 times that of obese nonusers and approximately 10 times that of nonobese nonusers. Five prospective cohort studies were identified as indirect evidence, and all found increased risk for VTE as BMI increased, suggesting a dose-response relationship between BMI and risk for VTE. No studies on the contraceptive patch or vaginal ring were identified that met the inclusion criteria., Conclusion: Limited evidence of Level II-2, fair quality, concerning whether CHC use modifies the risk of AMI and stroke in obese women is inconclusive, while a single study of Level II-2, poor quality, found that obese COC users may be at higher risk for CVT compared with normal-weight nonusers. Both COC use and higher BMI increase risk for VTE, and the greatest relative risks are for those with both risk factors based on a body of evidence graded as Level II-2, fair to poor quality. It is not possible to estimate absolute risk of VTE among women with both of these risk factors; however, the absolute risk of VTE in healthy women of reproductive age is small., (Published by Elsevier Inc.)