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October 27, 1978

High-dose methaqualone inhibits platelet aggregation

JAMA. 1978;240(18):1940. doi:10.1001/jama.1978.03290180014003

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Soon after methaqualone (Quaalude) became popular as a "street" hypnotic drug, it became obvious that serious hemorrhages occurred in many people who used it. Initially some clinicians postulated that this resulted from an increased vascular permeability and drug-induced changes in calcium metabolism.

Now a Canadian pharmacologist, Donald G. Mills, PhD, from the University of Western Ontario reports that in toxic doses methaqualone may lead to a defect of platelet function. This may partly explain the bleeding associated with the drug, which increasingly is being used both as a recreational and suicidal agent.

In his experiments Mills studied human and rabbit blood platelets. The human platelets were incubated with methaqualone for nine minutes and then mixed with either collagen or adenosine diphosphate (ADP), both of which normally induce aggregation. The rabbits first received injections of methaqualone; blood samples were then drawn 30 and 60 minutes after drug injection. Next, platelet-rich plasma