Doxycycline Drug Interactions
The following sections explain in detail the potentially negative interactions that can occur when doxycycline is taken with any of the medications listed above.
If doxycycline is taken with products containing aluminum, calcium, magnesium, or iron, your body may not absorb doxycycline adequately. To avoid this interaction, it is a good idea to take doxycycline at least two hours before or six hours after any products with aluminum, calcium, magnesium, or iron.
Barbiturate medications may decrease the level of doxycycline in the blood, perhaps making it less effective. Check with your healthcare provider before taking doxycycline with a barbiturate.
Bile Acid Sequestrants
Bile acid sequestrants may bind to doxycycline in the digestive tract, preventing it from being properly absorbed. This may make doxycycline less effective. Separate your doses of doxycycline and a bile acid sequestrant by as much time as possible (at least two hours or more).
Birth Control Pills
Despite the longstanding belief that antibiotics interact with birth control pills, several studies have shown that most antibiotics do not increase the risk of pregnancy in women taking birth control pills. Nevertheless, there have been reports of birth control pill failure in women who have taken antibiotics. Ask your healthcare provider about whether or not you need a backup method of birth control. In many situations, it is better to use backup rather than to take any risk of an unintended pregnancy.
Bismuth subsalicylate may decrease the absorption of doxycycline. It is best to take doxycycline at least two hours before or six hours after taking bismuth subsalicylate.