An overdose of lorazepam can be fatal.

This explains why one lorazepam dose, despite lorazepam's shorter serum half-life, has more prolonged peak effects than an equivalent diazepam dose. However, adverse effects such as behavioural disinhibition may make benzodiazepines inappropriate for some acutely psychotic patients. The intermediate oxime is then reacted with chloracetyl chloride, and upon heterocyclization 6-chloro-2-chlormethyl-4-(2′-chlorophenyl)quinazolin-3-oxide is formed. Do not use Ativan without your doctor's consent if you are pregnant. Synergistic adverse effects may also occur when lorazepam is administered with other drugs such as opioids or other hypnotics. If you have any of these conditions, you may need a dose adjustment or special tests to safely take Ativan. Lorazepam was first introduced by Wyeth Pharmaceuticals in 1971 under the brand names of Ativan and Temesta. 3. Five participants in a sleep study were prescribed lorazepam 4 mg at night, and the next evening three subjects unexpectedly volunteered memory gaps for parts of that day, an effect that subsided completely after 2–3 days' use. However, in critically ill patients, propofol has been found to be superior to lorazepam both in effectiveness and overall cost; as a result, the use of propofol for this indication is now encouraged, whereas the use of lorazepam for this indication is discouraged.