Source: Medicines & Healthcare Products Regulatory Agency (GB) Revision Year: 2019 Publisher: Pfizer Limited, Ramsgate Road, Sandwich, Kent, CT13 9NJ, United Kingdom
Pharmacotherapeutic group: Benzodiazepine derivatives
ATC code: N05BA06
Ativan is a benzodiazepine with anxiolytic, sedative, hypnotic, anticonvulsant and muscle relaxant properties.
Ativan Injection is readily absorbed when given intramuscularly. Peak plasma concentrations occur approximately 60-90 minutes following intramuscular administration.
Ativan is metabolised by a simple one-step process to a pharmacologically inactive glucuronide. There is minimal risk of accumulation after repeated doses, giving a wide margin of safety.
There are no major active metabolites.
The elimination half-life is about 12-16 hours when given intramuscularly or intravenously.
Lorazepam glucuronide, the major metabolite of lorazepam, has no demonstrable CNS activity in animals.
No evidence of carcinogenic potential emerged in rats and mice during an 18-month study with oral lorazepam.
A study of the mutagenic activity of lorazepam on Drosophila melanogaster indicated that this agent was mutationally inactive.
A pre-implantation study in rats was performed with oral lorazepam at a 20 mg/kg dose that showed no impairment of fertility.
Nonclinical research has shown that administration of anesthetic and sedation drugs that block N-methyl-D-aspartate (NMDA) receptors and/or potentiate gamma-aminobutyric acid (GABA) activity can increase neuronal cell death in the brain and result in long term deficits in cognition and behavior of juvenile animals when administered during the period of peak brain development. Based on comparisons across nonclinical species, the window of vulnerability of the brain to these effects is believed to correlate with human exposures in the third trimester of pregnancy through the first year of life, but may extend to approximately 3 years of age. While there is limited information of this effect with lorazepam, since the mechanism of action includes potentiation of GABA activity, a similar effect may occur. The relevance of these nonclinical findings to human use is unknown.
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