Use of chloroquine in shock.

One group of dogs received single doses of intramuscular chloroquine and another group served as a control. The dogs were subjected to haemorrhagic shock and then retransfused with their own blood after two hours of shock. The chloroquine-treated dogs had normal PA pressures after correction of acidosis and significantly smaller increases in the pulmonary vascular resistance. The results are similar but less marked than those obtained with aspirin. Chloroquine inhibited in vitro platelet aggregation by 50% and was not associated with any increased bleeding. This may be an advantage when used in patients with multiple trauma or increased bleeding tendency.