Drug Interaction Report

Antibiotics such as doxycycline may reduce the effects of estradiol in some women. If you are using estradiol for birth control, you may be at increased risk for pregnancy or breakthrough bleeding. Be sure to alert your doctor if you are having any vomiting and/or diarrhea as this too can impact how well estradiol works. Talk to your doctor or pharmacist to determine if you should use an alternative or additional form of birth control during or after treatment with doxycycline. In addition, some birth control preparations may include "placebo" non-hormonal pills that contain iron. If you are taking these iron-containing pills during treatment with doxycycline, you should separate the dosing times by several hours so that the iron does not interfere with absorption of the antibiotic. Ask your doctor or pharmacist for information on when best to take these medications. If you are using estradiol for a purpose other than birth control, please let your doctor know if you have any questions or notice any changes in how well estradiol is working. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

Grapefruit juice may increase the blood levels of certain medications such as norgestimate. You may want to limit your consumption of grapefruit and grapefruit juice during treatment with norgestimate. However, if you have been regularly consuming grapefruit or grapefruit juice with the medication, then it is advisable for you to talk with your doctor before changing the amounts of these products in your diet, as this may alter the effects of your medication. Contact your doctor if your condition changes or you experience increased side effects. Orange juice is not expected to interact.

Consumer information for this interaction is not currently available.

GENERALLY AVOID: The oral bioavailability of quinolone and tetracycline antibiotics may be reduced by concurrent administration of preparations containing polyvalent cations such as aluminum, calcium, iron, magnesium, and zinc. Therapeutic failure may result. The proposed mechanism is chelation of quinolone and tetracycline antibiotics by di- and trivalent cations, forming an insoluble complex that is poorly absorbed from the gastrointestinal tract. Reduced gastrointestinal absorption of the cations should also be considered.

MANAGEMENT: Concomitant administration of oral quinolone and tetracycline antibiotics with preparations containing aluminum, calcium, iron, magnesium, and/or zinc salts should generally be avoided. Otherwise, the times of administration should be staggered by as much as possible to minimize the potential for interaction. Quinolones should typically be dosed either 2 to 4 hours before or 4 to 6 hours after polyvalent cation preparations, depending on the quinolone and formulation. Likewise, tetracyclines and polyvalent cation preparations should typically be administered 2 to 4 hours apart. The prescribing information for the antibiotic should be consulted for more specific dosing recommendations.

Information for this minor interaction is available on the professional version.

Information for this minor interaction is available on the professional version.