Hello dear
I understand your concern
Yes antibiotics decrease the effectiveness of the birth control pill.
It depend on the type of the antibiotics.
Following are the antibiotics decrease the effectiveness of the birth control pill:
Rifampicine, Amoxicillin, ampicillin,
griseofulvin,
metronidazole and
tetracycline, sulfamethoxazole/trimethoprim, tetracycline, minocycline, and
nitrofurantoin.
Very light brown discharge could be due to
implantation bleeding.
So it should be confirmed by the urine pregnancy test.
You can also confirm the pregnancy by blood HCG test. (will give positive result even 10 days after the sex)
So birth control pill may decrease the effectiveness of the birth control pill by decrease the concentration of the active hormone in the blood as it increase the metabolism in the liver.
Avoid stress, take healthy diet, drink plenty of water and do regular exercise.
Hope this may help you
Contact HCM for further health query
Best regards
Dr. Sagar