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Midazolam as an anticonvulsant antidote for organophosphate intoxication—A pharmacotherapeutic appraisal
Author(s) -
Reddy Sandesh D.,
Reddy Doodipala Samba
Publication year - 2015
Publication title -
epilepsia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.687
H-Index - 191
eISSN - 1528-1167
pISSN - 0013-9580
DOI - 10.1111/epi.12989
Subject(s) - midazolam , anticonvulsant , status epilepticus , medicine , pharmacology , anesthesia , antidote , benzodiazepine , seizure threshold , diazepam , gabaa receptor , flumazenil , epilepsy , receptor , toxicity , sedation , psychiatry
Summary Objective This review summarizes the therapeutic potential of midazolam as an anticonvulsant antidote for organophosphate ( OP ) intoxication. Methods Benzodiazepines are widely used to treat acute seizures and status epilepticus ( SE ), a neurologic emergency of persistent seizures that can lead to severe neuronal damage or death. Midazolam is a benzodiazepine hypnotic with a rapid onset and short duration of action. Results Midazolam is considered the new drug of choice for persistent acute seizures and SE , including those caused by neurotoxic OP s and nerve agents. Midazolam is a positive allosteric modulator of synaptic γ‐aminobutyric acid ( GABA ) A receptors in the brain. It potentiates GABA ergic inhibition and thereby controls hyperexcitability and seizures. Midazolam is administered intravenously or intramuscularly to control acute seizures and SE . Due to its favorable pharmacokinetic features, midazolam is being considered as a replacement anticonvulsant for diazepam in the antidote kit for nerve agents. Clinical studies such as the recent Rapid Anticonvulsant Medication Prior to Arrival Trial ( RAMPART ) trial have confirmed the anticonvulsant efficacy of midazolam in SE in prehospital settings. Significance In experimental models, midazolam is effective when given at the onset of seizures caused by nerve agents. However, benzodiazepines are less effective at terminating seizures when given 30 min or later after OP exposure or seizure onset, likely because of internalization or downregulation of synaptic, but not extrasynaptic, GABA A receptors, which can lead to diminished potency and seizure recurrence.