Lorazepam

By Lauren R. Forsythe, PharmD, MBA, DICVP; Rania Gollakner, BS, DVM, MPH

What is lorazepam?

Lorazepam (brand names Ativan®, Lorazepam Intensol®) is a benzodiazepine medication used off label to treat behavior problems such as anxiety, fears, and phobias in cats and dogs. It can also be used to treat seizures or to stimulate appetite in cats.

Many drugs are commonly prescribed for off-label use in veterinary medicine. “Off label” means the drug is being used in a way that has not been reviewed or approved by the U.S. Food and Drug Administration (FDA) or Health Canada. In these instances, follow your veterinarian’s directions and cautions carefully, as they may be significantly different from those on the label.

How is lorazepam given?

  • Lorazepam is given by mouth in the form of a tablet or liquid. It can also be given as an injection in the hospital. 
  • It may be given with or without food. If vomiting occurs when dosed on an empty stomach, give future doses with food. 
  • Tablets dissolve quickly in the mouth, so if pilling is difficult, place the pill in the check followed by a treat a minute later to facilitate swallowing. 
  • Measure liquid forms carefully.
  • When using lorazepam for behavioral triggers, give it about an hour before the triggering event. 
  • Do not leave your pet unattended the first time this medication is used and monitor your pet for side effects. 
  • If using long-term, do not stop this medication abruptly or rebound effects may occur.

This medication should take effect within 1 to 2 days, and improvements in clinical signs should follow.

What if I miss giving my pet the medication?

Give the missed dose as soon as you remember, and then wait the recommended amount of time between doses. Never give your pet two doses at once or give extra doses.

Are there any potential side effects?

Lorazepam may cause the following side effects:

  • sleepiness
  • muscle weakness
  • incoordination
  • increased appetite (in cats)
  • drooling
  • aggressive or unusual behavior
  • increased activity 
  • increased anxiety
  • vocalization

Serious adverse reactions may occur. If any of the following signs develop, contact your veterinarian immediately:

  • yellowing of the skin, gums, or eyes
  • lack of appetite or depression (in cats)

This short-acting medication should stop working within 24 hours, although effects can be longer in pets with liver or kidney disease. Do not stop this medication abruptly or rebound effects may occur.

Are there any risk factors for this medication?

Lorazepam should NOT BE USED in pets

  • that are allergic to it or other benzodiazepines. 
  • with severe breathing problems or liver disease. 

Lorazepam should be USED WITH CAUTION in:

  • pets that are pregnant or lactating
  • pets with kidney disease
  • pets with glaucoma
  • pets that are debilitated or geriatric
  • working dogs

Are there any drug interactions I should be aware of?

The following medications should be used with caution when given with lorazepam:

  • antacids
  • antihypertensive agents
  • carbonic anhydrase inhibitors
  • central nervous system depressant agents
  • fluoxetine
  • hepatic enzyme inducers or inhibitors
  • theophylline/aminophylline
  • tricyclic antidepressants

It is important to tell your veterinarian about any medications (including vitamins, supplements or herbal therapies) that your pet is taking before starting any treatment.

Is any monitoring needed with this medication?

  • No specific monitoring is required while your pet is taking this medication. 
  • Your veterinarian may monitor your pet to be sure that the medication is working. 
  • Monitor your pet for serious side effects.

How do I store lorazepam?

  • Store tablets at room temperature between 68°F and 77°F (20°C and 25°C) in a tight container and protect from direct sunlight. 
  • Store the liquid in the refrigerator between 36°F and 46°F (2°C and 8°C) and protect from light.

Lorazepam is a controlled substance, which means that it has been designated by the Drug Enforcement Administration (DEA) as having a potential for diversion to people other than the patient it was prescribed for. Use of a controlled substance in any person or animal other than that for which it is prescribed is illegal. Therefore, this medication should be stored in a locked cabinet or safe that cannot be easily moved, with access limited to only those that need to administer the medication. Monitor the amount of medication remaining to ensure the expected amount is present.

What should I do in case of emergency?

If you suspect an overdose or an adverse reaction to the medication, call your veterinary office immediately. If they are not available, follow their directions in contacting an emergency facility.

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