Lorazepam is available in tablets and as a solution for intramuscular and intravenous injections. It is also available as a parenteral patch.

Dosage

Daily doses vary greatly, from 0.5 mg at bedtime for insomnia to 2.5 mg every 6 hours or more in the acute treatment of mania, before firstline drugs (such as lithium or 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 recur and treatment for some days may be necessary. Sometimes haloperidol is given concomitantly.

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 (anterograde amnesia) such as therapeutic interventions (endoscopies, etc.), which is a desirable effect. But in these cases the risk is taken that a patient could later make 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 incalcuable residual effects of the drug like tiredness, vertigo, hypotension etc. Also, the patient should not drive a car or handle machines for 24 hours after injection.

Disadvantages

Lorazepam, like other benzodiazepines, can cause psychological and/or physical dependence. Withdrawal symptoms similar in character to those of alcohol and barbiturates have been observed after abrupt discontinuation, therefore, a gradual taper is recommended over a period of weeks or even months, depending on the length of time it was used and the dosage taken.

The likelihood of abuse, dependence and withdrawal symptoms is substantially greater with lorazepam relative to other benzodiazepines because of its short half-life, higher potency and stronger binding to the GABA receptor complex. In this regard it behaves like alprazolam (short half-life and high potency) and clonazepam (long half-life and high potency).

Long term therapy may lead to cognitive deficits, however this is reversible upon discontinuation.

Lorazepam belongs to the Food and Drug Administration (FDA) pregnancy category D which means that it is likely to cause harm to the unborn baby, although this is very rarely seen. Lorazepam given near the time of birth may cause floppy infant syndrome and withdrawal symptoms in the infant.

In some cases there can be paradoxical effects with benzodiazepines, such as increased hostility and aggression. This is thought by some doctors to be due to disinhibition, and is therefore more likely to occur in those with preexisting personality disorders who may have less than average inhibition.

Abuse

Those with preexisting substance abuse disorders or addictive personalities are more likely to abuse medications such as lorazepam, and care should be taken when prescribing it on an outpatient basis. It is often used in an inpatient setting to assist with detox.