Interactions with doxycycline

What are the interactions with doxycycline?

Tell your doctor about all the medicines you are taking.

Doxycycline can interact with many different medicines so it is very important that you tell your health professional about all the medicines you are taking — including prescription, over-the-counter and complementary medicines (herbal, ‘natural’, and vitamin and mineral supplements). This is because all medicines, including herbal and natural medicines, can cause side effects and may interact with doxycycline.

Do not take doxycycline if you are taking medicines containing the following active ingredients.

  • Oral retinoids (isotretinoin or acitretin, used to treat acne and tretinoin used to treat leukaemia): if you are taking an oral retinoid (e.g. Roaccutane) you should not be prescribed doxycycline. This is because the combination of these medicines increases the chance of raised fluid pressure inside the brain (benign intracranial hypertension), which can lead to brain injury.

Take doxycycline at least 2 hours before or after medicines containing the following active ingredients.

  • Antacids (to counteract stomach acid) can prevent doxycycline from being absorbed into your body, resulting in less doxycycline in your blood to fight your infection. You can prevent this by taking doxycycline at least 2 hours before or after antacids.
  • Mineral supplements containing iron, calcium, magnesium or zinc can all prevent doxycycline from being absorbed into your body, resulting in less doxycycline in your blood to fight your infection. You can prevent this by taking doxycycline at least 2 hours before or after these supplements.

Doxycycline may also interact with medicines containing the following active ingredients.

  • Methotrexate (used to suppress swelling or inflammation and the immune response, e.g. if you have cancer or rheumatoid arthritis): doxycycline may increase the methotrexate concentration in the blood, which can increase the chance of toxic effects if you are taking a high dose of methotrexate.
  • Rifampicin and rifabutin (antibiotics used to treat another bacterial infection) reduces the effect of doxycycline, and you may need a higher dose of doxycycline.
  • Warfarin (used to prevent blood clots): doxycycline can increase the effect of warfarin and this will increase the risk of bleeding. Your dose of warfarin may need to be decreased.
  • Strontium ranelate (used to treat osteoporosis) may react with doxycycline chemically to reduce its absorption into your blood stream, resulting in less doxycyline to fight your infection. You will have to stop taking strontium ranelate until the day after you have finished the course of doxycycline.

Medicinewise tip

To check if your medicine contains this active ingredient, look on the packaging of your medicine for the active ingredient name, or use our Medicines Finder.

Can I drink alcohol if I am taking doxycycline?

Drinking alcohol in moderation is unlikely to interact with doxycycline or cause additional side effects.

Find out more about drinking alcohol when you are taking antibiotics.

Will doxycycline affect my contraceptive?

Doxycycline won’t affect your hormone contraceptive.

Rifampicin and rifabutin are the only types of antibiotic that are known to interact with some forms of hormone contraceptives, such as the combined contraceptive pill, making it less effective.

Find out more about antibiotics and contraception.

Phone for medicines information

Call NPS Medicines Line on 1300 MEDICINE (1300 633 424) to get information about your prescription, over-the-counter and complementary medicines (herbal, ‘natural’, vitamins and mineral supplements) from a pharmacist. Your call will be answered by healthdirect Australia.

References
  • Rossi S, ed. Australian Medicines Handbook [online]. Adelaide: AMH, July 2012.
  • Sweetman S, ed. Martindale: The complete drug reference [online]. London: Pharmaceutical Press (accessed 18 October 2011).
  • Antibiotic Expert Group. Therapeutic Guidelines: Antibiotic version 14; Doxycycline. Melbourne: Therapeutic Guidelines Limited, 2012 (accessed 27 March 2012).