USE OF MANNITOL IN EXOGENOUS AND ENDOGENOUS INTOXICATIONS

Enhanced elimination in acute barbiturate poisoning - a systematic review

CONTEXT

Despite a worldwide decline in barbiturate use, cases of acute poisoning with severe toxicity are still noted, particularly in developing countries. Severe poisonings often require prolonged admission to an intensive care unit, so enhanced elimination might be useful to hasten recovery. Information regarding the efficacy of these techniques for individual barbiturates is not available in standard textbooks.

OBJECTIVE

To determine the evidence supporting the effect of enhanced elimination and its role in the management of acute barbiturate poisoning.

METHODS

A systematic review was conducted using broad search criteria in three databases. All potentially relevant articles were obtained, and reference lists were manually reviewed. Ninety-four publications fulfilling inclusion criteria were located. Studies were classified as controlled or uncontrolled, and clinical and pharmacokinetic end points were manually extracted. If not directly stated, standard pharmacokinetic methods were used to calculate the clearance and efficiency of enhanced elimination techniques for each barbiturate and tabulated for direct comparison. PROSPECTIVE CONTROLLED CLINICAL TRIALS: Two of the 94 publications were prospective controlled studies (only one stated that allocation was via blinded randomisation), and both assessed the effect of multiple-dose activated charcoal for acute phenobarbital poisoning. These studies demonstrated enhanced elimination with a decrease in elimination of half-life from approximately 80 to 40?h, but only one study reported clinical benefits. UNCONTROLLED SERIES AND SINGLE CASE REPORTS: Sufficient data to determine the clearance due to enhanced elimination were available in only 52 of these papers. Barbiturate clearances by enhanced elimination varied markedly among studies. While extracorporeal modalities appeared to increase the direct clearance of many barbiturates, there was insufficient information to confirm a clinical benefit.

CONCLUSIONS

There is limited evidence to support the use of enhanced elimination in the treatment of poisoning with most barbiturates. There is no role for urine alkalinisation, while multiple-dose activated charcoal may be useful for most phenobarbital and possibly primidone poisonings. Extracorporeal techniques appear to enhance elimination, but the clinical benefits, relative to the potential complications and cost, are poorly defined. Extracorporeal techniques such as haemodialysis and haemoperfusion can be considered for patients with life-threatening barbiturate toxicity such as refractory hypotension.

Phenol burns and intoxications

Phenol burns and intoxications are life-threatening injuries. Roughly 50 per cent of all reported cases have a fatal outcome. Only a small number of cases have been reported with high serum concentrations after phenol burns who survived. In our own experience a patient with 20.5 per cent total body surface area deep partial skin thickness phenol burns and serum concentrations of 17,400 micrograms/litre survived after immediate and repeated treatment of the scalds with polyethylene glycol (PEG) and silver sulphadiazine. A literature review of experiences with phenol intoxications reveals the advantages of PEG application. Questions on the need for enforced diuresis and haemodialysis as well as the initial treatment procedures are discussed. Advantages of different solutions for local therapy are reported.

Intracranial hemorrhage and amphetamine usage. Review of the effects of amphetamines on the central nervous system

A 25-year-old man died after an intravenous injection of 100 mg of methedrine. Postmortem studies showed visceral congestion, lung edema, pericardial petechiae, centrolobular necrosis of the liver, and diffuse subarachnoid blood, intracranial vasculitis and cerebritis in the absence of aneurysms, arteriovenous malformations or chronic hypertension. A review of the English-language literature produced 3 other cases of fatal amphetamine-induced intracranial hemorrhage and seven nonfatal cases. Some were the result of overdose, others of hypersensitivity. Angiographic evidence suggests that such hemorrhages result from the development of fibrinoid necrosis and the formation of microaneurysms in the small intracerebral vessels.

Severe drug overdose: results of treatment

The incidence and management of severe drug overdose patients over a five-year period is presented, together with results and complications. Emphasis is placed on the importance of conservative measures with minimal need for more aggressive methods of treatment.

Hemorrhage in normal man. II. Effects of mannitol on plasma volume and body water dynamics following acute blood loss

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