COMMENTS ON DRUGS USED FOR CHEMOPROPHYLAXIS Since antimalarial drugs may cause some side-effects, the seriousness of any side-effect should be weighed up against the risk and
seriousness of contracting malaria. In most cases it is advisable to continue taking the drug.
CHLOROQUINE Chloroquine is relatively cheap and available without a prescription. It can be safely used
during pregnancy, lactation and in young children. Chloroquine should be used with caution in patients with epilepsy, cardiac or renal disease.
It is usually well tolerated, with most side effects being mild and reversible. The side-effects8 include:
* headache * nausea, vomiting (reduced if taken with a meal) * diarrhoea * pruritus
* skin eruptions and itching of the palms, soles of the feet and scalp * impaired vision
Serious side-effects are rare but may occur wth long term use. Periodic eye examinations are recommended if chloroquine is used for extended periods.
PROGUANIL It is considered to be
one of the best tolerated antimalarial drugs. It has a very good safety profile and can be used during pregnancy and for children. Proguanil rarely causes side effects when used in
prophylactic doses. Reported side effects9 include:
* mild gastric intolerance, which usually subsides as treatment is continued * vomiting and abdominal discomfort * mouth ulcers * skin reactions * hair loss
MEFLOQUINE
Mefloquine should not be used for longer than 1 year at a time. The following people should not take mefloquine:
* pregnant women or for 3 months before conception * children weighing under 15 kg
* patients with a history of epilepsy or psychiatric disorders * people with seizure disorders * people with cardiac conduction abnormalities
* people with depression * people requiring fine coordination such as pilots, scuba divers, mountaineers (it may interfere with fine motor-coordination)
* patients on beta blockers, calcium channel blockers, digitalis or on cyclic antidepressant therapy.
The following side-effects10 may occur when taking mefloquine:
* dizziness or disturbance of balance * gastro-intestinal disturbances
Less frequent side-effects10 that have been reported are:
* headache, myalgia, feeling of weakness, visual disturbances * palpitations, bradycardia, irregular pulse and extrasystoles, AV-block
* hair loss, rash or pruritis, urticaria * convulsions
* psychological changes, e.g. depressive mood, confusion, anxiety, hallucinations, paranoid reactions * transient elevation of transaminases
* leukopenia or leukocytosis and decrease of platelets
If signs of unexplained anxiety, depression, restlessness or confusion are noticed, these may be considered prodromal to convulsions and the drug must be stopped. Travellers taking mefloquine, who find continued side effects unacceptable, should switch to either chloroquine plus proguanil or doxycycline and not take mefloquine
again. If mefloquine is used for prophylaxis, halofantrine should not be used for treatment since it may lead to potentially fatal prolongation of the QTC interval. DOXYCYCLINE
Doxycycline is usually well tolerated and the most common adverse effects11 are:
* gastro-intestinal disturbances such as nausea and diarrhoea * photosensitivity (characterised by an exaggerated sunburn reaction)
* various dermatological reactions * vaginal candidiasis
Doxycycline is contraindicated during pregnancy, in breast-feeding mothers and in children under 8 years of age, as it can seriously damage tooth development.
Doxycycline is not recommended for longer than 3 months (due to lack of safety data for long-term use of daily 100 mg administration). It is an option to consider for epileptic
patients who have to enter a high-risk chloroquine-resistant malaria area. The guidelines are
endorsed by the Medical Association of South Africa. |
