search results for flagyl

back to: pharmacy | ask your pharmacist

Do antibiotics interact with birth control pills?

Certain antibiotics can interact with birth control pills, making the birth control pills less effective and pregnancy more likely. Spotting - or ‘mid-cycle’ bleeding - may be the first sign that an antibiotic is interfering with the effectiveness of your birth control pills.

Antibiotics that have been shown to interact with birth control pills include rifampin (brand name Rifadin), and to a lesser extent, penicillin (Veetids), amoxicillin (Amoxil), ampicillin (Omnipen), sulfamethoxazole/trimethoprim (Septra or Bactrim), tetracycline (Sumycin), minocycline (Minocin), metronidazole (Flagyl), and nitrofurantoin (Macrobid or Macrodantin).

To help women avoid pregnancy while taking an antibiotic - and for at least one week afterward - doctors generally recommend they use a condom or >spermicide as a back-up method of birth control. If you are taking both antibiotics and birth control pills, be sure to check with your doctor about how long you should continue to use a back-up method. Also, discuss any other questions you may have about this information.

Sources:
Dickey, R.P. Managing Contraceptive Pill Patients. EMIS Inc.,1998.
Hansten, P.D, J.R. Horn. Drug Interactions Analysis and Management, Applied Therapeutics, 2000.
Dipiro, J,T, Pharmacotherapy A Pathophysiologic Approach. Fourth Edition. Appleton &Lange. 1999.
Health. “Birth Control Pills”. http://www.mayoclinic.com. Mayo Clinic Health. Last accessed 11/15/2006.

This answer prepared 3/18/2001.
This information updated 11/15/2006.

>penicillin
>amoxicillin
>ampicillin
>sulfamethoxazole/trimethoprim
>tetracycline
>minocycline
>metronidazole
>nitrofurantoin

You searched for "Flagyl"

Here's what we found

Please click a question below for your pharmacist's response.

•	Is there a drug interaction between Flagyl and alcohol?
•	Do antibiotics interact with birth control pills?
•	Are there any interactions with milk thistle?
•	Are there any prescription treatments for bacterial vaginosis (BV)?
•	Are there any prescription medications for Crohn’s disease?
•	Are there any drug interactions with progesterone (Progest, Prometrium)?
(1 - 6 of 6)