Side effects
Do antibiotics stop the pill working?
Quick answer
Most antibiotics, like amoxicillin, doxycycline and azithromycin, do not stop the pill working. The big exceptions are rifampicin and rifabutin, used for TB, which make pills and the implant much less effective. Some epilepsy and HIV medicines and the herbal remedy St John's wort do the same.[src]
Most antibiotics are fine
The idea that "antibiotics cancel the pill" comes from older advice. Current UK guidance from the FSRH says antibiotics that do not induce liver enzymes do not reduce the effectiveness of hormonal contraception, so no extra precautions are needed.[src] That covers the antibiotics Filipinos are most often prescribed for UTIs, tooth infections, throat infections and skin infections, such as amoxicillin, co-amoxiclav, cefalexin, doxycycline, azithromycin and ciprofloxacin.
The catch is not the antibiotic but the illness. If the infection or the medicine makes you vomit within 2 hours of a pill, or gives you severe diarrhea, that can count as missed pills.[src] See what if I vomit after taking my pill.
TB treatment: the one that matters in the Philippines
Tuberculosis is common in the Philippines, and standard TB treatment includes rifampicin for months. [TODO: source: WHO Global TB Report or DOH NTP data on TB burden in the Philippines] Rifampicin and rifabutin are strong enzyme inducers: they make the liver break down contraceptive hormones faster, so the levels drop too low to rely on.[src]
This affects:[src]
- Combined pills, such as Trust (levonorgestrel + ethinylestradiol)
- Progestin-only pills, such as Daphne (lynestrenol)
- The implant
Methods that are not affected include the copper IUD, the hormonal IUD and the DMPA injection.[src] These are the usual options to discuss if you are starting TB treatment. The effect can last for about 4 weeks after you finish the enzyme-inducing medicine. [TODO: source: FSRH guideline wording on the 28-day period after stopping an enzyme inducer] Tell your TB DOTS clinic or health center that you use birth control. They can help you switch.
Other medicines to check
- Some epilepsy medicines, for example carbamazepine, phenytoin, phenobarbital and topiramate.[src]
- Some HIV medicines, especially certain older protease inhibitors and efavirenz. Your HIV clinic will know which ones.[src]
- St John's wort, a herbal remedy sold for low mood.[src]
- Lamotrigine works the other way: combined pills can lower lamotrigine levels, so seizure control may change.[src]
Herbal and "slimming" products bought online rarely list their ingredients clearly. If you take any, show the label to a pharmacist.
What to do
- Whenever a doctor prescribes something, say "I am on birth control" and name your brand.
- Ask the pharmacist when you buy it. Filipino pharmacists can check interactions in seconds.
- If you are on rifampicin or rifabutin, use condoms now and talk to a doctor about switching to an IUD or the injection.
Not sure about your medicine?
Ask the prescribing doctor or a pharmacist. If you had sex while unsure, read emergency contraception and talk to a doctor today.
Frequently asked questions
Nakakawala ba ng bisa ng pills ang antibiotics?
Karamihan ng antibiotics, gaya ng amoxicillin, ay hindi. Ang rifampicin at rifabutin na gamot sa TB ay nagpapahina sa pills at implant. Sabihin sa doktor na nag-pi-pills ka.
Do I need condoms while taking amoxicillin on the pill?
Not because of the amoxicillin. Current FSRH guidance says it does not reduce pill effectiveness. You only need extra protection if you vomit soon after pills or miss pills.
I am on TB treatment. Which birth control works?
Rifampicin and rifabutin make pills and the implant unreliable. The copper IUD, hormonal IUD and DMPA injection are not affected. Talk to your TB clinic or a doctor about switching.
This guide is for information. Talk to a doctor before starting, stopping or switching birth control.
Sources
- Drug interactions with hormonal contraception (guideline), FSRH (UK) Added during build. [TODO: link the exact guideline page]
- Managing missed pills (Family Planning Handbook), WHO and Johns Hopkins CCP