levetiracetam and Poisoning

Lamotrigine toxicity can cause coma, seizures, and intraventricular conduction disturbances, and treatment options include good supportive care. We report two cases of lamotrigine poisoning in which multiple-dose activated charcoal may have shortened the elimination half-life of lamotrigine.. A 21-year-old woman ingested 15.6 g lamotrigine, 14 g levetiracetam, and 15 mg clonazepam. She became comatose and developed generalized tonic seizure. One hour post-ingestion, 50 g activated charcoal was administered. Starting 11 h post-ingestion, 25 g activated charcoal was administered every 4 h for 4 doses. The peak concentration of serum lamotrigine was 49.5 µg/mL, and the elimination half-life after commencement of multiple-dose activated charcoal was 6.5 h.. A 46-year-old woman ingested 0.3 g lamotrigine and 0.1 g topiramate twice, 2 h apart. She became drowsy, complained of blurred vision, vertigo, nausea, and vomited. An initial dose of 50 g activated charcoal was administered at 4.5 h post-second ingestion, and subsequent doses of 25 g (total of 3 doses) were administered every 4 h, commencing at 8.5 h post-second ingestion. The peak concentration of serum lamotrigine was 19.9 µg/mL, and the elimination half-life after commencement of multiple-dose activated charcoal was 9.3 h.. The mean elimination half-life of lamotrigine in healthy volunteers and epileptic patients receiving lamotrigine monotherapy is 22.8-37.4 h. In our two cases, multiple-dose activated charcoal may have shortened the elimination half-life of lamotrigine, possibly by inhibiting enterohepatic circulation. Multiple-dose activated charcoal should be considered an option for treating lamotrigine poisoning.

Topics: Adult; Anticonvulsants; Charcoal; Epilepsy; Female; Humans; Lamotrigine; Levetiracetam; Middle Aged; Poisoning; Young Adult

Levetiracetam (Keppra) is a new anticonvulsant used to treat partial complex seizures that is also being investigated for its mood-stabilizing properties. Although its precise mechanism of action is unknown, levetiracetam does not appear to directly interact with the GABA system. We report the first intentional overdose with levetiracetam including clinical effects and serial serum concentrations.. A 38-year-old woman reportedly ingested 60 (500 mg) tablets of levetiracetam that she used as a mood-stabilizing medication for bipolar disorder. She had no other prescription medications available and no other medical history. She vomited 4 hours after ingestion and presented to the ED 2 hours later. In the ED, the patient was obtunded and was intubated secondary to respiratory depression. Her only other significant clinical finding was diminished deep tendon reflexes. Serum ethanol, lithium, carbamazepine, phenytoin, and valproic acid levels were all negative as was a subsequent urine screen for drugs of abuse. Her levetiracetam serum concentration was 400 microg/mL at 6 hours, 72 microg/mL at 18 hours, and 60 microg/mL at 20.5 hours (therapeutic serum concentration is 10-37 microg/mL). The elimination half-life was calculated to be 5.14 hours. She was extubated the next hospital day and recovered without sequelae.. In overdose, levetiracetam is sedating and causes respiratory depression, however, recovery is rapid with supportive care. This is the first reported case of levetiracetam overdose; serial serum concentrations suggest first-order elimination even at concentrations 10-40 fold higher than therapeutic.

Topics: Adult; Anticonvulsants; Bipolar Disorder; Drug Overdose; Female; Half-Life; Humans; Levetiracetam; Neurologic Examination; Piracetam; Poisoning; Respiration, Artificial; Respiratory Insufficiency; Suicide, Attempted