Travel Health Service Anti-malarial chemoprophylaxis
Travel health Tips

Anti-malarial chemoprophylaxis

For effective prevention against malaria, travellers should first be aware of the risk of contracting malaria. Adopting measures to prevent being bitten by mosquitoes is still the best and the first line of defense. The preventive measures include wearing long-sleeved clothes and long trousers when going out at night, applying effective insect repellent (containing DEET) over exposed parts of the body, and staying in accommodation with air conditioning or mosquito screens and nets. Clothing and nets impregnated with permethrin will make them more effective in avoiding mosquito bites. Anti-mosquito sprays or insecticide dispensers could also be used indoors. These simple first line measures will help to prevent malaria and other mosquito-borne diseases such as yellow fever, dengue fever and Japanese encephalitis.

There is at present no effective vaccine against malaria. Depending on individual travel itinerary, antimalarial pills may be required. There are four drugs commonly used in antimalarial chemoprophylaxis. The drug of choice is determined by the species and patterns of drug resistance of the malaria in the destinations and the current physical condition and past medical history of the traveller.

(1) Chloroquine

This drug should be taken one week before and throughout the journey, then continue for 4 weeks after leaving the area.

Dose : 5mg base per kg once a week

<4 mths 25mg 4-11 mths 50mg
1-2 yrs 75mg 3-4 yrs 100mg
5-7 yrs 125mg 8-10 yrs 150mg
11-13 yrs 250mg >14 yrs 300mg

Adverse effects  
Occasional: pruritus, nausea, headache
Rare: skin eruption, blurred vision, convulsion,impaired hearing, blood dyscrasia
Contraindicated: generalised psoriasis, epileptic, allergy to quinine compounds.

(2) Proguanil

This drug should be taken one day before and throughout the journey, then continue for 4 weeks after leaving the area.

Dose: 3mg per kg daily

<8mths 25mg 8mths-3yrs 50mg
4-7 yrs 75mg 8-10yrs 100mg
11-13 yrs 150mg >14 yrs 200mg

Adverse effects  
Occasional: nausea, diarrhea, mouth ulcers
Rare: haematuria

(3) Mefloquine

This drug should be taken one week before and throughout the journey, then continue for 4 weeks

after leaving the area.

Dose : 5mg per kg once a week

<3mths not recommended 3-23 mths 1/4 tab
2-3 yrs 1/3 tab 4-7 yrs 1/2 tab
8-10 yrs 3/4 tab >11 yrs 1 tab

(one tablet contains 250mg)

Adverse effects  
Frequent:
nausea, diarrhea, dizziness, syncope, extrasystoles
Rare: severe neuropsychiatric syndrome
Caution: avoid pregnancy, cardiac disease
Contraindicated: aircrew, epileptic, psychiatric disorders, first 3 months of pregnancy, allergy to quinine compound

(4) Doxycycline

This drug should be taken one day before and throughout the journey, then continue for 4 weeks after leaving the area.

Dose : 1.5mg salt per kg daily

<8 yrs contraindicated 8-10yrs 50mg
11-13 yrs 75mg >14 yrs 100mg

Adverse effects  
Occasional:
nausea, diarrhea, candida vaginitis
Rare: skin photosensitivity
Caution: avoid pregnancy

The traveller should strictly follow the guidance of physician in order to achieve the maximal protective effect offered by antimalarial chemoprophylaxis. If the traveller experiences severe adverse effects of the drugs during travel, which are so severe that continuation of prophylaxis becomes difficult, he should seek local medical advice.