Parenteral Chloroquine for Treating Falciparum Malaria

There is no information and therefore no consensus on how chloroquine should be ad-ministered to persons with severe malaria. Although widely considered dangerous, paren-teral chloroquine is extensively used. We studied the acute disposition and toxicity of in-travenous (iv), intramuscular (im), subcutaneous (sc), and oral chloroquine in 60 adult Zambian patients hospitalized with falciparum malaria. Plasma concentration profiles after parenteral administration were characterized by wide fluctuations between peak and trough values. Absorption of im and sc chloroquine was rapid, with a median time to peak concentration of 30 min and a peak plasma concentration five times higher than after oral administration. The pharmacokinetic data suggest that the acute toxicity of parenteral chloroquine is related to transiently high concentrations in blood and result from incomplete distribution out of a relatively small central compartment. Parenteral chloroquine may be administered safely by simply giving smaller, more-frequent doses than are currently used or, in the case of iv administration, by using continuous infusion. Chloroquine is the most widely prescribed antimalar-ial drug in the world [1]. Despite increasing resistance of Plasmodium falciparum in recent years, chloro-quine remains the drug of choice for treating sensi-tive strains of this parasite and also for treating the other three human malarias. Oral chloroquine is safe, cheap, and effective in uncomplicated malaria, but there are doubts concerning the safety of chloroquine when administered parenterally. Intravenous chlo-roquine causes predictable hypotension [2], and im administration has been associated with sudden Received for publication 14 April 1986, and in revised for