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Ovid: Oxford Handbook of Tropical Medicine

Editors: Eddleston, Michael; Pierini, Stephen; Wilkinson, Robert; Davidson, Robert Title: Oxford Handbook of Tropical Medicine, 2nd Edition Copyright ©2005 Oxford University Press (Copyright 2005 by M. Eddleston, S. Pierini, R. Wilkinson, and R. Davidson) > Table of Contents > Chapter 2 > Chapter 2A – Malaria > Chemoprophylaxis Chemoprophylaxis Chemoprophylaxis against malaria rarely provides full protection and measures should be taken at all times to reduce mosquito bites. Insecticide-treated bednets should be used: they reduce morbidity and mortality from malaria in children. Individuals should be aware of malarial symptoms, which may be non-specific, and report early for a blood film if malaria is suspected. Travellers to malarial areas should preferably begin prophylaxis 1 week (2–3 weeks in the case of mefloquine) before arrival, and must continue for 4 weeks after departure, except in the case of Malarone, where prophylaxis may be commenced the day before entry into a malarious area and ended 7 days after return. Any febrile illness occurring within 1 year of travel could be malaria. For long-term non-immune residents consideration should be given to the balance between the risks of infection and the side-effects of chemoprophylaxis. It may be possible to target prophylaxis during the transmission season alone. Drugs used in prophylaxis

  • Proguanil: used for prophylaxis in pregnant women and non-immune individuals in areas of low risk only. It is more commonly used in combination with chloroquine (see below). Dose 200 mg PO od in adults, including pregnant women. Children <1 yr 25 mg/day; 1–4 yrs 50 mg/day; 5–8 yrs 100 mg/day; and 9–14 yrs 150 mg/day. A folic acid supplement should be taken during pregnancy.
  • Chloroquine is used in combination with proguanil in low-risk areas, in pregnant women, and other individuals who cannot tolerate other antimalarials. Dose: 300 mg (as base) PO weekly in adults, including pregnant women. Children require 5 mg/kg weekly.
    • Chloroquine binds to melanin in the retina, causing concern that long-term prophylaxis may lead to visual impairment/blindness. Total life time exposure therefore should not exceed 100 g (~6 yrs of continuous usage). Twice-yearly retinal screenings should be performed in anyone who has taken 300 mg of chloroquine weekly for >6 yrs.
  • Mefloquine is now a favoured drug for the prophylaxis of malaria in many areas where chloroquine resistance is present. Dose: 250 mg PO weekly in adults; in children >45 kg 62.5 mg weekly in children 3 months–5 yrs, 125 mg for 6–8 yrs, 187.5 mg for 9–14 yrs). Mefloquine is not recommended in neonates.
  • Doxycycline: useful as an alternate to mefloquine for short term prophylaxis of up to 8 weeks. Dose: 1.5 mg/kg PO od, up to a max of 100 mg. Do not use in children <12 yrs and in pregnant and lactating women. Conception should be avoided for >1 week after its use.
  • Pyrimethamine-dapsone (Maloprim®): used in areas of chloroquine resistance (with chloroquine to cover P. vivax) when mefloquine or doxycycline are contraindicated. However, availability has become a limiting factor. Dose: 12.5 mg pyrimethamine plus 100 mg dapsone (1 tablet of Maloprim) PO weekly for adults. Children: 1–5 yrs ¼ dose, 6–11 yrs ½ dose, >11 yrs full adult dose. Pyrimethamine-sulfadoxine (Fansidar®) is no longer used for prophylaxis due to the risk of Stevens–Johnson syndrome and bone marrow toxicity.

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Fig. 2A.6

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