What is the risk of thrombosis associated with Phencyclidine (PCP) use?

Thrombosis Risk Associated with Phencyclidine (PCP) Use

Phencyclidine (PCP) use is associated with an increased risk of thrombosis due to its effects on cardiovascular function, particularly through hypertensive crisis and platelet activation mechanisms.

Mechanisms of PCP-Induced Thrombosis Risk

• PCP has been documented to cause significant hypertensive crises, which can damage vascular endothelium and trigger thrombotic events 1
• As with other drugs of abuse, PCP may induce a prothrombotic state through multiple mechanisms including increased platelet activation, endothelial damage, and altered blood viscosity 2
• The acute cardiovascular effects of PCP include dramatic increases in blood pressure that can lead to endothelial injury, a key initiating factor in thrombosis formation 1, 3
• PCP-induced malignant hyperthermia, a documented complication of intoxication, can trigger systemic inflammatory responses that further increase thrombosis risk 3

Clinical Presentations Related to Thrombosis Risk

• Severe hypertensive episodes during PCP intoxication can occur suddenly and may lead to vascular complications including thrombotic events 1
• Documented cases of sudden death associated with PCP use have included findings of pulmonary embolism at autopsy, suggesting thrombotic complications 4
• PCP intoxication can present with several clinical patterns that may increase thrombosis risk:
  • Comatose state (10.6% of cases) with immobility increasing venous thrombosis risk 4
  • Catatonic syndrome (11.7% of cases) with prolonged immobility 4
  • Rhabdomyolysis (2.2% of cases), which can trigger disseminated intravascular coagulation 4

Management Considerations

• Patients with PCP intoxication should have continuous monitoring of blood pressure in an intensive care unit to detect and manage hypertensive crises that could lead to thrombotic events 1
• For patients with known cardiovascular disease who have used PCP, the risk of thrombotic events may be significantly higher, similar to the increased risk seen with other prothrombotic substances 2
• In cases of severe PCP intoxication with prolonged immobility, thromboprophylaxis should be considered, following similar principles to those used in other high-risk immobile patients 5

Risk Factors for Increased Thrombosis with PCP

• Pre-existing cardiovascular disease may significantly increase the risk of PCP-induced thrombotic events 2
• Concomitant use of other substances with prothrombotic effects may have synergistic effects with PCP 2
• Prolonged immobility during PCP-induced catatonic states or coma increases venous thrombosis risk 4
• Severe hyperthermia, which can occur with PCP use, is associated with increased platelet activation and endothelial dysfunction 3

Clinical Pitfalls and Caveats

• The thrombosis risk from PCP may be underrecognized in emergency settings where focus is primarily on managing behavioral and neurological symptoms 6
• PCP's variable clinical presentation (stimulant, depressant, hallucinogenic effects) may mask underlying thrombotic events 6
• The unpredictable nature of PCP's effects means that thrombotic risk cannot be reliably predicted based on the amount consumed 6
• Patients with PCP intoxication may be unable to report symptoms of thrombosis due to altered mental status, making clinical vigilance particularly important 4