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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.
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