Lindsay Murray

Topiramate Overdose: Clinical and Laboratory Features

Limited data exist on overdose with new antiepileptic drugs. We reviewed the medical records of two patients who took a topiramate overdose as a suicide attempt. We recorded their medical and seizure histories, concomitant antiepileptic medications, neurologic examination, and laboratory findings at the time of presentation following the overdose. We also recorded their progress and the evolution of laboratory abnormalities. Both patients progressed to coma and had generalized convulsive status epilepticus, requiring intubation and treatment with benzodiazepines. Both patients recovered within 2 days but had a non-anion-gap metabolic acidosis that persisted for 5-6 days. Physicians should carefully monitor patients treated with topiramate who develop signs of clinical depression. The non-anion-gap metabolic acidosis observed may be due to inhibition of renal cortical carbonic anhydrase.

A risk assessment based approach to the management of acute poisoning

Early assessment and management of poisoning constitutes a core emergency medicine competency. Medical and psychiatric emergencies coexist; the acute poisoning is a dynamic medical illness that represents an acute exacerbation of a chronic underlying psychosocial disorder. The emergency physician must use an approach that ensures early decisions address potentially time critical interventions, while allowing management to be tailored to the individual patient’s needs in that particular medical setting. This article outlines a rationale approach to the management of the poisoned patient that emphasises the importance of early risk assessment. Ideally, this approach should be used in the setting of a health system designed to optimise the medical and psychosocial care of the poisoned patient.

Prospective study of 101 patients with suspected drink spiking

Objective:  To evaluate cases of suspected drink spiking presenting to the ED by the prospective collection of standardized relevant historical, clinical and laboratory data.

Oral methotrexate overdose

Background: Methotrexate (MTX) is a folate antagonist used in the management of rheumatoid arthritis and as an antimetabolite in cancer chemotherapy. MTX toxicity following parenteral administration is well described, predictable on the basis of timed serum concentrations, and preventable by the administration of folinic acid. Although MTX toxicity has never been reported fol- lowing single oral overdose, many authorities recommend treatment with folinic acid. The objective of this study was to describe the clinical course following acute MTX ingestion and the utilization of MTX levels in refining the risk assessment. Methods: Following institution of a standard management protocol for acute MTX ingestion at the NSW Poisons information Centre, data was prospectively collected on all acute intentional or unintentional ingestions of methotrexate reported to the centre. The proto- col withheld immediate administration of folinic acid for ingestion of < 500 mg in adults or < 5 mg/kg in children, provided results of timed plasma MTX concentrations could be obtained within 24 hours. Follow-up full blood count was recommended for all patients at 7 days. Results: Between March 2004 and November 2005, 13 patients were reported to the centre: three paedi- atric unintentional and 9 adult intentional ingestions. One patient was lost to follow-up. Accidental ingestions: doses ranged from 2.5–12.5 mg. No child developed symptoms or required any treatment. Intentional ingestions: median ingested dose was 300 mg (Range 40–1000 mg). Table 1 below demonstrates the MTX levels for the intentional ingestions. No patient demonstrated any symptoms and no patient had a serum MTX level greater than that predicting toxicity (5 micromoles/L at 6 hours post-ingestion). Many patients were given folinic acid by the treating physician despite PIC recommendations. Three patients had follow-up full blood counts at 7 days post ingestion; all were normal. Further cases are being recruited. Conclusions: Single acute overdose of MTX does not result in serum MTX concentrations associated with toxicity. It is likely that folinic acid therapy can be safely withheld for ingestions of less than 500 mg in adults.