Faculty Bibliography

Background: Propoxyphene, an opioid structurally similar to methadone is marketed in combination with acetaminophen or salicylates. Propoxyphene is also a sodiumchannel blocker. Death from propoxyphene overdose may result from respiratory depression or wide-complex dysrhythmias. We report a death from wide-complex dysrhythmia following an intentional propoxyphene/ acetaminophen overdose. Case report: A 37-year-old agitated woman was brought to the ED by EMS. Vital signs: BP, 150/106 mmHg; pulse, 120 beats/min; respirations, 30 breaths/min; room air O2 saturation, 99%. She rapidly became bradycardic with a HR of 40 beats/ min and unresponsive with no measurable blood pressure. CPR and endotracheal intubation were performed, and atropine and epinephrine were given with electrical defibrillation. The systolic BP returned to 40-65 mmHg with a pulse of 30 beats/min. The ECG showed a QRS interval of 180 ms. Sodium bicarbonate, calcium chloride, a glucagon infusion (5 mg/h) and high-dose insulin was administrated without improvement. A transcutaneous pacer was applied but could not capture. Despite high dose infusion of norepinephrine and vasopressin she expired about 4 h later. Tablets of propoxyphene/ acetaminophen were brought in by family and her serum propoxyphene concentration was subsequently reported as 615 ng/mL (200-400 ng/mL). Case discussion: Propoxyphene overdoses are characterized by respiratory depression and sodium channel blockade. Despite significant toxicity, several studies show that propoxyphene's analgesic effect is no better than acetaminophen alone. In 2005, British authorities initiated phased withdrawal of propoxyphene as a result of over 300 deaths/year. In the US since the 1980s, there have been over 2,000 deaths from propoxyphene. At an FDA meeting to determine if propoxyphene should be withdrawn, 14 members voted to withdraw the drug and 12 against withdrawal. Despite this vote, the FDA ultimately decided against withdrawal and recommended a boxed warning about the potential cardiotoxicity. Conclusion: Propoxyphene overdose and fatalities continues to occur in the US. This raises questions about the risk/benefit of this combination product

Pregabalin is prescribed for neuropathic pain. We report the first case of pregabalin toxicity in a hemodialysis patient and her successful treatment with hemodialysis. The patient was a 30-year-old woman on long-term hemodialysis therapy who experienced significant myoclonus of the arms and legs when her dose of pregabalin was mistakenly increased. The drug has 3 properties that contribute to making it amenable to removal by hemodialysis: relatively low molecular weight (159.23 Da), relatively low volume of distribution (0.5 L/kg), and not bound to plasma proteins. We achieved hemodialysis clearance of 88.8 mL/min, which was associated with resolution of symptoms immediately after hemodialysis