Delorazepam, also known as chlordesmethyldiazepam and nordiclazepam, is a drug which is a benzodiazepine and a derivative of desmethyldiazepam. It is marketed in Italy, where it is available under the trade name EN and Dadumir. Delorazepam (chlordesmethyldiazepam) is also an active metabolite of the benzodiazepine drugs diclazepam and cloxazolam. Adverse effects may include hangover type effects, drowsiness, behavioural impairments and short-term memory impairments. Similar to other benzodiazepines delorazepam has anxiolytic, skeletal muscle relaxant, hypnotic and anticonvulsant properties. Indications Delorazepam is mainly used as an anxiolytic because of its long elimination half-life; showing superiority over the short-acting drug lorazepam. In comparison with the antidepressant drugs, paroxetine and imipramine, delorazepam was found to be more effective in the short-term but after 4 weeks the antidepressants showed superior anti-anxiety effects. Delorazepam is also used as a premedication for dental phobia for its anxiolytic properties. High doses of Delorazepam may be administered the night before a dental (or other medical) procedure in order to provide relief from anxiety-associated insomnia that night with the effects persisting long enough to sufficiently treat anxiety the next day. Delorazepam has also demonstrated effectiveness in treating alcohol withdrawal. Availability Delorazepam is available in tablet and liquid drop formulations. The liquid drop formulation is absorbed more quickly and has improved bioavailibility. Pharmacology Delorazepam is well absorbed after administration, reaching peak plasma levels within 1 – 2 hours. It has a very long elimination half-life and can still be detected 72 hours after dosing. Bioavailability is about 77 percent. Peak plasma levels occur at just over one hour after administration. Significant accumulation occurs of delorazepam due to its slow metabolism; the elderly metabolise delorazepam and its active metabolite slower than younger individuals, resulting in a dose of delorazepam accumulating faster and peaking at a higher plasma concentration than an equal dose administered to a younger individual. The elderly also have a poorer response to the therapeutic effects and a higher rate of adverse effects. The elimination half-life of delorazepam is 80–115 hours. The active metabolite of delorazepam is lorazepam and represents about 15 - 24 percent of the parent drug (delorazepam). The pharmacokinetics of delorazepam are not altered if it is taken with food, except for some slowing of absorption. Delorazepams potency is approximately equal to that of lorazepam, being ten times more potent by weight than diazepam (1 mg delorazepam = 1 mg lorazepam = 5 mg diazepam), typical doses