Background
A new form of implantable subdermal contraceptive device (Nexplanon) is available in the market since 2001 and provides 99% effective contraception. However, similar to other hormonal contraception, its effectiveness is compromised with the use of cytochrome P450 inducing drugs resulting in an unplanned pregnancy. Despite this theoretical risk, little is known on the outcome of concomitant use of anti-tuberculosis medications and Implants.
Case presentation
A 26 years old GIII PII who has been using Nexplanon for the past 2 years and 7 months presented to the family planning referral clinic with the diagnosis of failed implant and second-trimester pregnancy at gestational age of 19 weeks. She was initiated on rifampicin based anti-tuberculosis 8 months prior to her presentation for the diagnosis of tuberculosis of the lymph nodes.
Conclusion
All health professionals should be aware of the possible reduced effectiveness of certain hormonal contraceptives due to concomitant use of hepatic cytochrome P450 enzyme-inducing medications. Women should be given detailed counseling about the potential for drug interaction. The discussion should include the use of other alternative methods. A multidisciplinary approach with consultation or referral to reproductive health specialists is crucial for optimal management of women who are at increased risk of contraceptive failure and unintended pregnancy.