Jill asked
Hi. I'm taking Ciprofloxacin currently. The condom broke while I was having sex. Can I take plan B while taking ciprofloxacin? Thank you
Answer
There is some uncertainty regarding whether or not ciprofloxacin, a fluoroquinolone antibiotic, affects the efficacy of oral contraceptives. This includes high dose emergency contraceptives such as Plan B and My Way. Most studies indicate the ciprofloxacin does not affect birth control pills and will not decrease efficacy. However, there may be a small number of people who are affected, who can be difficult to identify.
Plan B - Ciprofloxacin Interaction
One comprehensive study reviewed multiple publications to determine the overall effect of a variety of antibiotics on oral hormonal birth control. The study concluded that most antibiotics do not significantly affect hormonal concentrations obtained from birth control pills and therefore, do not decrease their efficacy. Per the study, the following antibiotics did not affect birth control hormone concentrations in the body :
- Ampicillin
- Cipro (ciprofloxacin)
- Clarithromycin
- Doxycycline
- Metronidazole
- Ofloxacin
- Tetracycline
Studies have only definitively shown one family of antibiotics having a significant effect on birth control, the rifampin family of antibiotics. These medications are associated with birth control pill failure and pregnancy.
Having stated the above, it is important to note that there are studies that have shown a small number of individuals who experienced significant decreases in birth control hormone levels while taking antibiotics, even if the overall population didn't show a change on average. Most of the authors of these studies conclude that because females most at risk for birth control failure aren't easily identified, and due to the serious consequences of unintended pregnancy, short term back-up birth control may be prudent.
Studies that have looked at ciprofloxacin specifically, and not entire classes of antibiotics, have shown that ciprofloxacin does not appear to negatively effect birth control hormone concentrations and should not cause contraceptive failure. There are no studies that indicate ciprofloxacin affects high dose emergency contraception (e.g. Plan B) either. You can feel comfortable taking ciprofloxacin and Plan B together as no study has indicated that the effectiveness of either will be affected.
