warfarin and Serotonin-Syndrome

Many life-threatening drug interactions are predictable, avoidable events. Emergency medicine physicians have a responsibility to recognize and prevent drug interactions. Keeping current on the many pharmaceutical therapies,their pharmacology, and potential drug interactions currently represents one of the biggest challenges for emergency medicine practitioners. Using current drug interaction resources and knowing the limited number of medications that are responsible for the most serious drug interactions can ease this seemingly overwhelming burden greatly. Clinicians need to be particularly vigilant when prescribing drugs for patients who are taking medications with potential for drug interactions leading to serious consequences.

Topics: Anti-Inflammatory Agents, Non-Steroidal; Anticoagulants; Cardiotonic Agents; Cytochrome P-450 Enzyme Inhibitors; Cytochrome P-450 Enzyme System; Digoxin; Drug Interactions; Drug Monitoring; Drug Therapy, Combination; Drug Utilization; Emergency Medicine; Emergency Treatment; Humans; Intestinal Absorption; Metabolic Clearance Rate; Nonprescription Drugs; Physician's Role; Risk Factors; Serotonin Agents; Serotonin Syndrome; Tissue Distribution; United States; Warfarin

To report the occurrence of a transient ischemic attack (TIA) temporally related to the initiation of paroxetine.. A 57-year-old white man with a history of intermittent atrial fibrillation and hypercholesterolemia developed slurred speech and a facial droop 3 days after starting paroxetine. He was diagnosed with a TIA, hospitalized, and given anticoagulation treatment. The presenting symptoms resolved, but recurred when paroxetine was restarted 2 days later.. Platelets secrete serotonin, which mediates vasoconstriction through stimulation of 5-HT2a receptors. This is counterbalanced by the release of the vasodilator nitric oxide upon serotonin stimulation of endothelial 5-HT1 receptors. In conditions such as atherosclerosis, the damage to the endothelium leads to a greater vasoconstrictive response. Paroxetine has been reported to weakly inhibit norepinephrine reuptake and nitric oxide production in addition to increasing serotonergic activity, potentially compounding the vasoconstrictive response. An objective causality assessment revealed that the TIA was probably an adverse event resulting from use of paroxetine.. Use of paroxetine and other selective serotonin-reuptake inhibitors may result in changes of the vasculature and subsequent ischemic events in predisposed patients.

Topics: Anticoagulants; Drug Interactions; Heparin; Humans; Ischemic Attack, Transient; Male; Middle Aged; Paroxetine; Selective Serotonin Reuptake Inhibitors; Serotonin Syndrome; Warfarin