In response to: Midazolam-induced acute dystonia reversed by diazepam.

Dear Editor,

We read with interest the article titled “Midazolam-induced acute dystonia reversed by diazepam.”[1] Indeed, midazolam-induced acute dystonia is reported in the literature, though not very commonly. Not just dystonia, midazolam is also a culprit for other adverse reactions like agitation, excitement, mental confusion, tremors, athetosis, laryngospasm.[23] The proposed mechanism of action of extrapyramidal symptoms after midazolam administration is the loss of inhibition by the inhibitory neurotransmitter GABA, which is a property of Benzodiazepines in general.[4] Both midazolam and diazepam acting at the same receptor site should, therefore, theoretically result in the same response. It seems unlikely that another drug from the benzodiazepine family would resolve a dystonic reaction caused by midazolam. There are reports in the literature showing acute dystonias with diazepam or the commonly called “Street Valium”.[56] Most reports mention reversal of the dystonia after administration of the BZD antagonist “Flumazenil” or anti-cholinergic agents like “Physostigmine.”[378] In this case, the dystonic reaction did not subside with the administration of Flumazenil. It is unlikely that the acute dystonia was an untoward effect of midazolam, and another plausible explanation for acute dystonic reaction observed in the case must be sought.

The dose used in this case, as a premedication (0.2 mg/kg intravenously), appears high. The recommended dose of midazolam for premedication is 0.25-0.5 mg/kg orally, 1.0-2.5 mg for intravenous sedation and 0.1-0.2 mg/kg for induction of anesthesia.[9] The authors mention that throughout the period of dystonia, the sensorium was clear. The reason as to why such a high dose of midazolam was used in a 6-year-old girl remains unclear.