Antimalarial drugs rheumatoid arthritis

Hydroxychloroquine Plaquenil) and chloroquine Ara-len) are 4-aminoquinoline antimalarial drugs that possess modest DMARD activity. They are indicated for the treatment of rheumatoid arthritis and systemic lupus erythematosus their use as antimalarials is detailed in Chapter 53. The onset of action of these drugs is longer than that of other DMARDs, and their side effects are relatively mild. Because of this, these agents show promise as ingredients of combination therapies for rheumatoid arthritis. 

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. 

Chloroquine and related antimalarials are effective in rheumatoid arthritis and lupus erythematosus, but their mode of action is not known. The anthelmintic drug levamisole (186) is also effective but adverse effects limit its use. 

So far, the choice of quinine-like drugs to treat rheumatoid arthritis has been based on preliminary selection as antimalarials. Because the two types of action are presumably unconnected, there might be some value in a screening program aimed directly at rheumatoid disease. 

There are two classes of drugs, gold compounds and antimalarials which, whilst they have been shown to possess certain experimental anti-inflammatory activities, seem, on the basis of their clinical effects, to have a delayed action against rheumatoid arthritis. Their effect appears to be more selective than that of the salicylates and other drugs previously discussed. Indeed, in view of their favourable influence on the sheep-cell agglutination titre (SCAT), they may even modify the disease process itself. Control of the disease, however, is usually incomplete and their ultimate effect is doubtful . 

Bondeson J, Sundler R. Antimalarial drugs inhibit phospholipase A2 activation and induction of interleukin Ibeta and tumor necrosis factor alpha in macrophages imphcations for their mode of action in rheumatoid arthritis. Gen Pharmacol 1998 ... 

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