doxycycline in malaria prophylaxis

Last edited 12/2019 and last reviewed 12/2019

Summary: Doxycycline malaria prophylaxis (1,2,3):
  • acts as a suppressive prophylactic

  • 100mg daily (adult dose)

  • start one or two days before entering a malarious area and continue daily while abroad and daily for four weeks after travel

  • doxycycline is contraindicated in pregnancy and breast feeding, in children under 12 years of age and in patients who are allergic to tetracycline (1)

  • side effects
    • oesophagitis - especially if taken on an empty stomach and/or lying down soon after taking it
    • be aware of photosensitivity risk (3% (2)) - the rash fades slowly and therefore it is desirable that people using doxycycline as malaria prophylaxis avoid too much sun and use a high-factor sunscreen (1)
    • may predispose to vaginal candidiasis

  • seek specialist advice for stays over three months

  • doxycycline has been licensed for chemoprophylaxis of malaria (1)

Doxycycline as chemoprophylaxis for malaria (3)

Mode of action

  • doxycycline is lipophilic and acts intracellularly, binding to ribosomal mRNA and inhibiting protein synthesis. It acts as a suppressive prophylactic.

Efficacy

  • doxycycline is of comparable prophylactic efficacy to mefloquine

The capsules and solution of dispersible tablets should be swallowed with plenty of fluid in either the resting or standing position and the recipient should not lie down for at least 1 hour after ingestion to reduce the likelihood of oesophageal irritation and ulceration. If gastric irritation occurs, it is recommended that doxycycline is taken with food or milk. Studies indicate that the absorption of doxycycline is not notably influenced by simultaneous ingestion of food or milk

  • absorption of doxycycline may be impaired by concurrently administered antacids containing aluminium, calcium, magnesium or by oral zinc, iron salts or bismuth preparations. Intake of these substances should be separated from dosing with doxycycline as far as possible

Prophylactic regimen

  • dose 100 mg daily, starting 1 to 2 days before entering a malarious area, continuing throughout the time in the area and for 4 weeks after leaving the area

Contraindications

  • allergy to tetracyclines or to any ingredients of the capsules or dispersible tablets. Children under 12 years of age
  • use during pregnancy is contraindicated in the SmPC
  • the UK National Teratology Information Service states that doxycycline is best avoided for antimalarial prophylaxis during pregnancy. However, if required before 15 weeks' gestation it should not be withheld if other options are unsuitable, see www.toxbase.org
    • course of doxycycline, including the 4 weeks after travel, must be completed before 15 weeks' gestation
  • use while breast feeding is contraindicated in the SmPC
    • a Centers for Disease Control Expert Meeting on Malaria Chemoprophylaxis stated that doxycycline is excreted at low concentrations in breast milk and that the American Academy of Pediatrics assessed tetracycline as compatible with breast feeding
      • PHE view is that doxycycline should not be used in breast feeding unless other options are unsuitable, and its use is felt to be essential

Cautions

  • hepatic impairment. Patients taking potentially hepatotoxic drugs
  • renal impairment
  • Myasthenia gravis
  • Systemic lupus erythematosus
  • Candida infections may occur
  • prescriber should warn against excessive sun exposure (and advise on the correct use of a broad-spectrum sunscreen)

Interactions

  • drugs: The metabolism of doxycycline is accelerated by carbamazepine and phenytoin. In that situation try to advise another antimalarial. If not possible or acceptable to the traveller, increase the dose of doxycycline to 100 mg twice daily and counsel regarding measures to minimise the risk of adverse events. Tetracyclines possibly enhance the anticoagulant effect of coumarins (for example warfarin), and doxycycline may increase the plasma concentration of ciclosporin

  • Doxycycline is a non-enzyme-inducing antibiotic. The Faculty of Sexual and Reproductive Healthcare and the BNF advise that for combined oral contraceptives and for progestogen only oral contraceptives additional precautions are not required when using non-enzyme-inducing antibiotics. However, if the traveller suffers vomiting or diarrhoea, the usual additional contraceptive precautions should be observed

  • Vaccines: Possibly reduces the efficacy of oral typhoid vaccine if given simultaneously. Preferably should not be started within 3 days after the last dose of vaccine

Side-effects

  • doxycycline hydrochloride preparations have a low pH and may produce oesophagitis and gastritis, especially if taken on an empty stomach and/or just before lying down. Doxycycline may cause photosensitivity which is mostly mild and transient

  • doxycycline is a broad-spectrum antibiotic and may predispose to vaginal candidiasis

NB no protection can be 100% effective and so any fever or flu-like illness especially within the first three months could be malaria and needs immediate medical attention. This regime is not licensed for malaria prophylaxis.

The summary of product characteristics must be consulted before prescribing any of the drugs mentioned.

Reference: