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Lorazepam: 7 things you should know

Medically reviewed by Carmen Fookes, BPharm. Last updated on Feb 27, 2023.

1. How it works

  • Lorazepam calms and sedates and may be used to treat anxiety, as an anticonvulsant, or for its sedative effects.
  • Experts aren't exactly sure how lorazepam works, but believe its effects are due to its ability to strongly bind to the GABA-benzodiazepine receptor complex, which enhances the affinity for GABA (a neurotransmitter that blocks impulses between nerve cells in the brain). Low levels of GABA have been linked to anxiety, mood disorders, seizure disorders, and pain.
  • Lorazepam belongs to the class of medicines known as benzodiazepines.

2. Upsides

  • May be used for the short-term relief of anxiety (such as before surgery) or in the management of anxiety disorders (although studies have not documented use beyond 4 months).
  • Also available in an injectable form that may be used for the treatment of prolonged seizures.
  • May be used off-label (this means for an indication that has not been approved by the FDA but may still have a place in therapy) for some other indications such as lower back pain.
  • Generic lorazepam is available.

3. Downsides

If you are between the ages of 18 and 60, take no other medication or have no other medical conditions, side effects you are more likely to experience include:

  • Drowsiness, sleepiness, or dizziness are the most common side effects reported. Any one of these side effects may impair reaction skills and affect a person's ability to drive or operate machinery or increase the risk of falls. Alcohol may potentiate these effects and should be avoided.
  • Amnesia, confusion, unsteadiness, visual problems (blurred or double vision), sexual dysfunction, nausea, constipation, and several other side effects have also been reported.
  • May rarely cause respiratory depression (unusually slow and shallow breathing). The risk is greater with larger dosages of lorazepam, in people with pre-existing respiratory conditions, or if lorazepam is used in addition to other medications that also cause respiratory depression (such as opioids).
  • Lorazepam may increase the risk of depression or unmask depression or increase the risk of suicidal thoughts. Monitor for worsening of mood.
  • Lorazepam is potentially addictive and may cause both emotional and physical dependence. The lowest dose should be used for the shortest possible time. Lorazepam supplies may be sought out by drug seekers.
  • Withdrawal symptoms (including convulsions, tremors, cramps, vomiting, sweating, or insomnia) may occur with abrupt discontinuation; taper off slowly under a doctor's supervision.
  • Occasionally, paradoxical reactions (the opposite of what is to be expected) may occur. Symptoms include anxiety, agitation, rage, sleep disturbances, sexual disinhibition, or hallucinations.
  • People over the age of 50 may be more at risk of profound and prolonged sedation after IV administration of lorazepam.
  • May interact with several other medications including opioids, other medications that cause sedation (such as alcohol, antipsychotics, antidepressants, or sedative antihistamines), clozapine, probenecid, and valproate.
  • May not be suitable for some people including those with pre-existing respiratory disease (such as COPD or sleep apnea), a history of drug or alcohol abuse, at high risk of falls, women who are pregnant or breastfeeding, or people with renal or hepatic impairment. The elderly or frail may be especially sensitive to lorazepam's effects.

Note: In general, seniors or children, people with certain medical conditions (such as liver or kidney problems, heart disease, diabetes, seizures) or people who take other medications are more at risk of developing a wider range of side effects. View complete list of side effects

4. Bottom Line

  • Lorazepam may be used for the treatment of anxiety or as a preoperative medicine. It is potentially addictive and a withdrawal syndrome may be experienced upon discontinuation. Sedation is a common side effect.

5. Tips

  • May be taken with or without food. May be given in split doses, with the largest dose just before bedtime when used to relieve anxiety.
  • Take exactly as directed by your doctor. Do not increase or decrease the dosage without his or her advice. If you have been taking lorazepam for a long time do not stop suddenly as withdrawal reactions (blurred vision, insomnia, sweating, and rarely seizures) may occur. Your doctor will advise you about tapering off the dose. Keep out of sight of potential drug seekers.
  • Lorazepam may cause sleepiness and affect your ability to drive or perform other complex tasks. Avoid doing these activities if lorazepam has this effect on you.
  • Avoid drinking alcohol while taking lorazepam as it may enhance the side effects of sedation and respiratory depression.
  • Lorazepam may make you feel dizzy, increasing your risk of falls. Be careful when sitting or standing up after lying down.
  • If you think you have become dependent on lorazepam or are addicted to it, talk with your doctor.
  • Do not take any other medications with lorazepam including those bought over the counter without first checking with your pharmacist or doctor that they are compatible.

6. Response and effectiveness

  • The time-to-peak effects differ depending on the formulation of lorazepam used. Optimum effects when used preoperatively (including lack of recall or recognition) are seen within two hours of intramuscular (IM) administration) and 15-20 minutes after intravenous (IV) administration. Peak concentrations occur within two hours of oral administration.
  • Intended effects usually last six to eight hours, but may last longer in some people.

7. Interactions

Medicines that interact with lorazepam may either decrease its effect, affect how long it works, increase side effects, or have less of an effect when taken with lorazepam. An interaction between two medications does not always mean that you must stop taking one of the medications; however, sometimes it does. Speak to your doctor about how drug interactions should be managed.

Common medications that may interact with lorazepam include:

  • anti-anxiety medications, including other benzodiazepines, such as diazepam and oxazepam
  • anticonvulsants such as valproate
  • antidepressants, such as amitriptyline, imipramine, nortriptyline
  • antihistamines that cause sedation, such as diphenhydramine
  • barbiturates
  • duloxetine
  • monoamine oxidase inhibitors, such as selegiline, isocarboxazid, or phenelzine
  • opioid analgesics such as codeine, oxycodone and morphine
  • oral contraceptives
  • muscle relaxants such as cyclobenzaprine
  • probenecid
  • scopolamine
  • sleeping pills, such as zolpidem
  • some medications used to treat mental illness, such as clozapine and thioridazine
  • theophylline.

Alcohol may worsen the side effects of lorazepam such as drowsiness and dizziness.

Note that this list is not all-inclusive and includes only common medications that may interact with lorazepam. You should refer to the prescribing information for lorazepam for a complete list of interactions.


Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use lorazepam only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Copyright 1996-2023 Revision date: February 27, 2023.