[e-drug] Concurrent use of Co-trimoxazole and ACT in children (2)

["FHJansen" <Fhjansen@skynet.be>]

E-DRUG: Concurrent use of Co-trimoxazole and ACT in children (2)
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Dear Dr Koleade,

You are presenting an interesting question to E-drug. The comment of the moderator KM answers most of the questions. However, I should like to add a few remarks. The treatment of malaria with Artesunate SP involves a full treatment of SP administered as a single dose. This sulfonamide does have a long elimination half life but due to a very high protein binding it can only exert a proper antiparasite and antimicrobial action for about five days, in some case maybe a little longer. Pyrimethamine will be active for quite a longer time. 
During this period of 5 to 8 days it does not make sense to add another short acting sulfonamide like sulfamethoxazole in combination with timethoprim. The sulfonamide addition may create problems e.g (crystalluria) and will definitely not improve the patients condition (there is nothing to begained by having higher concentrations than Cmin for the free fraction in plasma water (non protein bound concentration). 
Recommendation: do not give Co-trimoxazole in the first 3 - 5 days after starting Artesunate + SP.

This problem can be overcome if for the malaria treatment another ACT is being used. For example Co-arinate (Dafra Pharma). In this medicament Artesunate is given over 3 days but the sulfonamide/pyrimethamine combination is spread over 3 days. It was calculated that with this regimen the folic acid inhibition will last between 12 and 18 days. This should be sufficiently long to treat nearly all concommittant infections sensitive to sulfonamide therapy. Hence, no need for co-trimoxazole.

For a discussion on sulfonamides and the differences see the website www.dafra.be.

Best regards

Dr. F.H. Jansen
Dafra Pharma nv
2300 Turnhout
Belgium
www.dafra.be
Fhjansen@skynet.be