Antimalarial drugs prophylactic

Chloroquine can cause seizures in patients with epilepsy. The mechanism is uncertain, but it may include reductions in inhibitory neurotransmitters and pharmacokinetic interactions that alter anticonvulsant concentrations. Tonic-clonic convulsions were reported in four patients in whom chloroquine was part of a prophylactic regimen. Antiepileptic treatment was required to control the seizures. None had further seizures after withdrawal of the antimalarial drugs (9). 

Fish DR, Espir ML. Convulsions associated with prophylactic antimalarial drugs implications for people with epilepsy. BMJ 1988 297(6647) 526-7. 

Proguanil is one of the antimalarial drugs most widely used for prophylactic purposes, usually in combination with chloroquine or atovaquone in malaria prophylaxis, and with atovaquone in malaria treatment (SEDA-21, 297). A biguanide, it is rapidly absorbed in standard doses and mainly excreted by the kidneys. Its antimalarial effect is due to its metabolite cycloguanU. However, its metabolism varies individually, and this is reflected in a variable degree of efficacy (SEDA-17, 328). 

Environmental criteria. Prophylactic use of antimalarial drugs is usually combined with a life in areas with high solar irradiance. 

Curd, F.H.S., Davey, D.G. and Rose, F.L. (1945) Studies on synthetic antimalarial drugs-X. Some biguanide derivatives as new types of antimalaiial substances with both therapeutic and causal prophylactic activity. Ann. Trap. Med. 39 208-214. 

P. falciparum. Quinine is therefore an effective suppressive agent but has no prophylactic or radically curative properties. It is, however, becoming increasingly important as a last resort for treating infections with strains of P. falciparum resistant to all other antimalarial drugs [10]. Nevertheless, quinine-resistant strains of P. falciparwn have now been reported in the field, from Vietnam [92]. 

The drug is effective against all four types of malaria with the exception of chloroquine-resistant P. falciparum Chloroquine destroys the blood stages of the infection and therefore ameliorates the clinical symptoms seen in P. malariae, P. vivax, P. ovale, and sensitive P. falciparum forms of malaria. The disease will return in P. vivax and P. ovale malaria, however, unless the liver stages are sequentially treated with primaquine after the administration of chloroquine. Chloroquine also can be used prophylactically in areas where resistance does not exist. In addition to its use as an antimalarial, chloroquine has been used in the treatment of rheumatoid arthritis and lupus erythematosus (see Chapter 36), extraintestinal amebiasis, and photoallergic reactions. 

Amodiaquine (Camoquin) is another 4-aminoquinoline derivative whose antimalarial spectrum and adverse reactions are similar to those of chloroquine, although chloroquine-resistant parasites may not be amodi-aquine-resistant to the same degree. Prolonged treatment with amodiaquine may result in pigmentation of the palate, nail beds, and skin. There is a 1 2000 risk of agranulocytosis and hepatocellular dysfunction when the drug is used prophylactically. 

Tests in man are, of course, the pinnacle of antimalarial evaluation procedures, and the factors governing such tests are similar to any organised clinical trial [23]. However, the search continues for a perfect animal model of hiunan malarias, and the similarity between human and simian malarias has prompted a number of investigations of their interrelationships. P. cynomolgi has long been used as a secondary screen for prophylactic activity to test drugs which showed activity in the primary screens [23], since the course and therapeutic response of this infection are directly parallel to those of human vivax malaria. Moreover, human infections with the simian... 

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