Lorazepam
From Freepedia
Lorazepam is classified as a sedative-hypnotic of the benzodiazepine class. It is available in tablets and as a solution for intramuscular and intravenous injections.
The main indication for its use are some forms of anxiety disorders, so it is also commonly known as an anxiolytic.
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Indications
- for the relief of anxiety disorders
- treatment of insomnia, particular if associated with severe anxiety
- treatment of symptoms associated with alcohol withdrawal
- as a supplanting drug for the initial treatment of depressions, mania and psychotic disorders
- longterm treatment of otherwise resistant forms of petit mal epilepsy
- acute therapy of status epilepticus
- acute therapy of catatonic states alone/or with haloperidol
- supportive therapy of nausea/emesis frequently associated with cancer-chemotherapy together with accepted firstline antiemetics
Pharmacological Data and Pharmacokinetics
Lorazepam is rapidly and nearly completely absorbed after any mode of application (oral, sublingual, i.m., i.v.). After i.v.-injection onset of action is within minutes and may be delayed to 30-45 minutes after oral/sublingual dose and up to 1 hour after i.m. use.
The duration of action depends on the dose and is normally 6 to 12 hours. The halflife of lorazepam in patients with normal liver function is 11 to 18 hours. Therefore, 2-4 daily doses are often needed.
A dose equivalent to 5 mg of diazepam is 500 micrograms (0.5 mg) of lorazepam. [1]. Other experts estimate a proportion of 1 to 5 (5mg diazepam equvalent to 1 mg lorazepam).
Lorazepam is a Schedule IV drug under the Convention on Psychotropic Substances[2].
Dosage
Daily doses vary greatly from 0.5 mg bedtime for insomnia and 2.5 mg every 6 hours and more in the acute treatment of mania, before the firstline drugs (lithium, valproic acid) control the situation.
Catatonia with inability to speak is very responsive and sometimes controlled with a single dose of 2 mg oral or slow i.v. injection. Catatonia may reoccur and treatment for some days may be necessary. Sometimes haloperidol is given concomittantly.
The control of status epilepticus requires slow i.v. injections of 2 to 4 (or even 8) mg. Patients should be closely monitored for respiratory depression and hypotensive effects.
In any case, dose requirements have to be individualized especially in the elderly and debilitated patients in whom the risk of oversedation is greater. Safety and effectiveness of lorazepam is not well determined in children under 18 years of age, but it is used to treat serial seizures. With higher doses (preferably i.v.-doses) the patient is frequently not able to recall unpleasant events (amnesia) such as therapeutical interventions (endoscopies etc.), which is a wanted effect. But in these cases the risk is given that a patient later makes unjustified allegations of sexual abuse during treatment due to poor recall.
After injections of Lorazepam the patient should normally not be released from hospital settings without a care-giving person (parent, spouse etc.) before 24 hours have elapsed, due to uncalcuable residal effects of the drug like tiredness, vertigo, hypotension etc. Also, the patient should not drive a care or handle machines for 24 hours after injection.
Disadvantages
Lorazepam, like other benzodiazepines, can cause dependence and withdrawal symptoms after cessation of a prolonged use. The likelihood of abuse, misuse and addiction as well as of withdrawal symtoms is substantially greater compared to other benzodiazepines because lorazepam is a highly potent benzodiazepine with rapid onset of action, experienced by some users as euphoria ('flash'). In this regard lorazepam behaves like alprazolam and clonazepam. Perhaps, also the relatively short halflife may play a role.
Long term therapy may lead to unreal feelings and motivations of the patient and a loss of social activity, loss of interest in occupational and spare-time actvities and cognitive deficits.
Therefore, lorazepam is usually not suited for long term treatment. Stresses of everyday life usually are not proper indications for its use, as they are best treated with psychotherapy.
Lorazepam belongs to the FDA pregnancy category D which means that it is likely to cause harm to the unborn baby.
In some cases there can be paradoxical effects with benzodiazepines, such as increased hostility and aggression.
Recreational Use
Any abuse of Lorazepam is dangerous and should be advised against. The following is for information purposes only:
- 'legimate use' : The so called 'prescription drug abuse' is most commom. People taking the drug for years without any special reason or indication, but without feeling as addicts, because they have a doctor's prescription.
- 'illegal use' : Special data is not available but as a highly potent benzodiazepine it might be used to help to come down from stimulant abuse in order to sleep or to terminate the action of LSD or other hallucinogens without unpleasant after-effects. It can be expected that Lorazepam has some street use to boost the euphoriant effects of opioids like heroin, perhaps it is already part of the stuff used without the knowledge of the user. The risk if used together with an opioid is to suffer respiratory depression or arrest.
- 'date rape drug' : Lorazepam has no particular taste and could in principal be misued as 'date rape drug'. But Flunitrazepam is the mostly used drug for this purpose. The action of Lorazepam together with alcohol is extremly dangerous (massive central depression commonly with unconsciousness and respiratory depression, permanent damage or death is possible).
Brands
- Ativan
- Temesta
- Tavor (in Europe)
External Links
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