What is dimenhydrinate?

Dimenhydrinate (brand names: Dramamine®, Gravol®, Travtabs®, Driminate®, Triptone®) is an antihistamine used to prevent motion sickness and to treat nausea, especially in dogs with vestibular disease. It has also been used for its sedative properties and to reduce itchiness associated with allergies.

Its use in cats and dogs to treat nausea and motion sickness is off label (extra label). 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 dimenhydrinate given?

• Dimenhydrinate is given by mouth in the form of a tablet or compounded liquid. It may also be given as an injection in the hospital.
• Measure liquid forms carefully.
• It may be given with or without food.
• If vomiting occurs on an empty stomach, give future doses with food.
• If using dimenhydrinate for motion sickness during travel, give it 30–60 minutes prior to travel.
• Only give products that contain dimenhydrinate as the only active ingredient. Do not give your pet any combination products.
• Give free access to water while giving this medication.

This medication will take effect quickly, in about 1 to 2 hours, and improvement in clinical signs should follow.

What if I miss giving my pet the medication?

If you miss a dose, give it as soon as you remember, and then continue with the regular dosing schedule. However, if it is almost time for the next dose, skip the missed dose and resume the regular dosing schedule. Do not give the pet two doses at once.

Are there any potential side effects?

Dimenhydrinate may cause the following side effects:

• Sleepiness
• Dry mouth
• Difficulty urinating
• Diarrhea (less common)
• Vomiting (less common)
• Lack of appetite (less common)

Serious adverse reactions may occur and may indicate an overdose. If any of the following signs develop, stop giving dimenhydrinate and contact your veterinarian immediately:

• Seizures
• Coma

Drug sensitivities can develop over time, with repeated exposure. Your pet may have no reaction after the first few doses but may develop a sensitivity later. It is important to watch for signs of an allergic reaction over the entire course of treatment.   

Other side effects may occur. If you notice anything unusual, contact your veterinarian immediately.  This short-acting medication should stop working within 24 hours, although effects can be longer in pets with liver or kidney disease.

Are there any risk factors for this medication?

DO NOT USE dimenhydrinate in pets that:

• Are allergic to it or similar antihistamines
• Are neonatal
• Are undergoing antigen skin testing within the next two weeks

USE WITH CAUTION in pets that:

• Have glaucoma
• Have seizures
• Have elevated thyroid levels
• Have heart disease
• Have high blood pressure
• Have enlarged prostate
• Have gastrointestinal or urinary blockage
• Have respiratory disease.
• Are geriatric (likely safe)
• Are pregnant or nursing (likely safe)

Are there any drug interactions I should be aware of?

Several medications should be used with caution when given with dimenhydrinate, including:

• Anticholinergic drugs
• Central nervous system depressants
• Tricyclic antidepressants

Dimenhydrinate may also interact with antigen skin testing; discontinue at least 2 weeks prior to allergy testing.

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

Is any monitoring needed with this medication?

There is no specific monitoring that needs to be done 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 dimenhydrinate?

Store this medication at room temperature and protect liquid forms from freezing.

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.