1.The toxicity and therapeutic efficacy of single intravenous injections of chloroquine dihydrochloride in doses of 5.7 to 14.9 mgm. of chloroquine base per kilogram of body weight have been studied in 110 patients with falciparum malaria.
2.The drug had been administered by three techniques—by syringe, both diluted with saline (25 patients) and undiluted (10 patients); and by intravenous infusion (75 patients).
3.The toxic effects varied directly with the speed of injection and appeared to be related principally to a depressor effect of the drug.
4.Following the rapid intravenous injection of undiluted chloroquine (6.0 to 10.8 mgm. of base per kilogram of body weight), the subjective reactions included dizziness, nausea, vomiting, haziness of vision, and drowsiness. A transitory decrease in systolic blood pressure (average, 26 mmg. Hg) was observed.
5.When administered by intravenous infusion in 500 ml. of physiologic saline, both subjective reactions and depression of systolic blood pressure were almost completely eliminated.
6.No serious toxic reactions were observed in this series of patients treated with chloroquine intravenously.
7.Single intravenous injections of chloroquine proved highly effective in terms of temperature response and disappearance time of trophozoites. Recrudescence of the disease was not observed in this series during short periods of post-treatment observation.
8.In view of the low order of toxicity and high degree of therapeutic efficacy, chloroquine administered intravenously is the method of choice for initiating treatment in falciparum malaria, especially in severely ill patients.
With the Technical Assistance of Kathryn Teeple.
Acknowledgment: The generous cooperation of Dr. Roberto Martinez F. is gratefully acknowledge.