Doxycycline How does it work? Doxycycline belongs to a group of antibiotics called tetracyclines. It is an antibiotic that has the ability to inhibit the growth of a wide variety of bacteria and certain other organisms. It works by preventing bacteria from producing proteins that are essential to them. Without these proteins the bacteria cannot grow, replicate and increase in numbers. Doxycycline therefore stops the spread of the infection and the remaining bacteria eventually die. Doxycycline is used to treat a wide variety of respiratory, urinary tract, eye and sexually transmitted infections, and various other infections caused by susceptible bacteria and micro-organisms. It is also used for severe acne, as it is active against the bacteria associated with acne, Propionebacterium acnes. This is a common type of bacteria that feeds on sebum produced by the sebaceous glands in the skin. It produces waste products and fatty acids that irritate the sebaceous glands, making them inflamed and causing spots. By controlling bacterial numbers, doxycycline brings the inflammation of the sebaceous glands under control, and the skin is allowed to heal. Doxycycline is also active against the parasite that causes malaria. It is sometimes used to treat malaria, and can also be used to prevent it when visiting high-risk malarial areas, in particular areas where the malaria parasite is resistant to chloroquine. What is it used for? Acne vulgaris Bubonic plague Chlamydia Cholera Chronic bronchitis Death and decay of tissue in a infected wound due to gas production by the infecting bacteria (gas gangrene) Disease caused by infection with Leptospira bacteria (Weil's Disease/leptospirosis) Disease of rodents and rabbits that can be transmitted to humans (tularaemia) Eye infections Gonorrhoea Infection caused by the bacteria brucella (brucellosis) Infection of the lungs and airways (lower respiratory tract infection) Infections of the urinary system Infections with bacteria transmitted by lice, fleas, ticks and mites (rickettsial infections) Infectious disease of parrots and man (parrot fever/psittacosis) Infectious disease of rodents that can be transmitted to humans (melioidosis) Inflammation of the sinuses Lesions in the groin and genitalia caused by a sexually transmitted bacteria (granuloma inguinale) Louse and tick-bourne relapsing fever Pneumonia Prevention of an infectious disease called Scrub typhus Prevention of infection with Leptospira bacteria (leptospirosis) Prevention of malaria Prevention of traveller's diarrhoea (enterotoxigenic E coli) Protozoal infection of the intestine (amoebiasis) Sexually transmitted infection that causes genital ulcers (chancroid) Syphilis Tetanus Treatment of malaria caused by chloroquine-resistant Plasmodium falciparum Warning! This medicine can cause the skin to react abnormally to direct sunlight and UV light, causing an exagerated sunburn reaction. Avoid exposing your skin to direct sunlight and UV light while taking this medicine. Stop taking this medicine and consult your doctor at the first sign of any skin reaction. If you are using this medicine as malaria prevention you should start taking it, as directed by your doctor, two days before you travel. You should continue taking it throughout your stay in the malarious region, and for a further four weeks after leaving. Doxycycline capsules should be taken with plenty of water while you are sitting or standing. Avoid taking them just before going to bed. This is to prevent the medicine irritating the throat. If you find the medicine irritates your stomach you can minimise this by taking it with food or milk. Occasionally this antibiotic may upset the natural balance of micro-organisms in the body, allowing those that are not susceptible to doxycycline to overgrow and cause infection. This may happen with yeasts such as Candida, resulting in thrush infections. If this happens, stop taking this medicine and see your doctor. Use with caution in Decreased liver function Long-term inflammation of skin and some internal organs (systemic lupus erythematosus) People taking medicines with potential to cause adverse effects on the liver Not to be used in Allergy to other tetracycline antibiotics, eg doxycycline, minocycline Breastfeeding Children under 12 years of age Pregnancy This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy. If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately. Pregnancy and Breastfeeding Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine. This medicine should not be used during pregnancy as it may be harmful to the unborn baby. Seek medical advice from your doctor. Significant amounts of this medicine may pass into breast milk. It should not be used by breastfeeding mothers. Discuss this with your doctor. Label warnings Avoid exposure of skin to direct sunlight or sun lamps. Do not take iron preparations or indigestion remedies at the same time of day as this medication. Take at regular intervals. Complete the prescribed course unless otherwise directed. This medication is to be taken with plenty of water.