From the Research
Rifampicin, a common anti-tuberculosis medication, significantly reduces the effectiveness of Implanon (etonogestrel implant) contraception, and therefore, alternative contraceptive methods should be used during TB treatment and for 28 days afterward. This interaction occurs because rifampicin increases liver enzymes that metabolize etonogestrel more quickly, lowering its concentration in the blood and reducing contraceptive efficacy 1. The most recent study on tuberculosis and pharmacological interactions highlights the importance of managing drug-drug interactions to improve treatment outcomes and patients' quality of life 1.
Key Considerations
- Rifampicin is a potent inducer of the cytochrome P450 enzyme group, which is involved in the metabolism of many drugs, including oral contraceptives like Implanon 2.
- The interaction between rifampicin and Implanon can lead to reduced contraceptive efficacy, and therefore, alternative contraceptive methods should be used during TB treatment and for 28 days afterward.
- Alternative options include using non-hormonal contraceptives like copper IUDs, which are not affected by TB medications, or considering injectable contraceptives like depot medroxyprogesterone acetate (DMPA), which may be less affected by enzyme inducers but still require more frequent administration (every 10 weeks instead of 12) 1.
Recommendations
- If taking rifampicin or other enzyme-inducing medications for TB treatment, use additional contraceptive methods during treatment and for 28 days afterward.
- Consider using non-hormonal contraceptives like copper IUDs or injectable contraceptives like DMPA.
- If continuing with Implanon, reliable barrier methods such as condoms should be used concurrently.
- After completing TB treatment, the Implanon implant may need replacement if it has been significantly compromised by long-term rifampicin exposure.
- Always discuss your specific situation with healthcare providers who can offer personalized advice based on your complete medical history and treatment regimen 3.