Drug Interaction Report

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

Taking norfloxacin with food or products that contain minerals like calcium, iron, magnesium and zinc can interfere with its absorption and reduce its levels in the blood and urinary tract. This may make the medication less effective in treating your infection. You should take norfloxacin on an empty stomach at least one hour before or two hours after eating a meal or consuming milk or other dairy products. Do not use mineral supplements, multivitamins, antacids, or other products that may contain calcium, iron, magnesium or zinc within the two-hour period before or after taking norfloxacin. Talk to your doctor or pharmacist if you have questions on how to take this or other medications you are prescribed. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medication without first talking to your doctor.

You may experience reduced absorption of mercaptopurine in the presence of food. Take mercaptopurine on an empty stomach 1 hour before or 2 hours after a meal. This will make it easier for your body to absorb the medication.

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.

Using caffeine together with norfloxacin may increase the effects of caffeine. Contact your doctor if you experience headache, tremor, restlessness, nervousness, insomnia, and increased blood pressure or heart rate. If your doctor does prescribe these medications together, you may need a dose adjustment or special test to safely use both medications. 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.