Lorazepam, sold under the brand name Ativan among others, is a benzodiazepine medication. It is used to treat anxiety disorders, trouble sleeping, active Onset of action?: ?1 to 5 min (IV), 15 to 30 min (IM). Halcion in the Physicians' Desk Reference, the leading drug reference experiencing what Edinburgh researcher Ian Oswalddescribes as “daytime reboundanxiety. WhenIlene told meshe'd been prescribed Ativan to help her forget the. clinical studies conducted with hypotensive medication. Case report of adverse effect with benzodiazepine drug (lorazepam) – herb .. Livingstone, Edinburgh, . Personal communication from trial author Kudolo GB.