THE PET PHARMACY By Wendy C. Brooks, DVM, DipABVP Educational Director, VeterinaryPartner.com

(for veterinary information only)

Brand Names: Bonine, Antivert, Meclizine Hydrochloride

Available in 25 mg chewable tablets; 12.5 mg, 25 mg, and 50 mg non-chewable tablets; and 25 mg and 30 mg capsules

Background

Carsickness is an important problem for many pets and while the commonly prescribed acepromazine has many benefits as an antinausea drug, its long-acting tranquilizing properties make it inconvenient for short trips. Fortunately, there are more appropriate alternatives. Ideally, for short-term relief of carsickness, we would like a medication with: minimal side effects; does not yield long-lasting drowsiness; and is conveniently dosed. Although meclizine hydrochloride is a human medication, it has proved to be quite helpful for relief of nausea in our pets.

How this Medication is Used

Meclizine hydrochloride is generally used for nausea relief due to motion sickness. It is also used to control the nausea resulting from vestibular disease, a syndrome characterized by vertigo and loss of balance.

For the prevention of motion sickness, meclizine hydrochloride should be given approximately 30 minutes before travel.

Side Effects

Meclizine hydrochloride is a member of the piperazine class of antihistamines. It may produce some drowsiness though nothing like the 6 to 8 hours of tranquilization yielded by its cousin acepromazine.

Most antihistamines have potential to cause any of a group of symptoms referred to as anticholinergic symptoms: urinary retention, dry mouth, increased heart rate, and exacerbation of glaucoma (elevated pressure within the eye). It may also reduce the ability to produce milk in lactating mothers.

Interactions with other Drugs

Meclizine hydrochloride should not be given in conjunction with other tranquilizing drugs, as such a combination may lead to excess sedation.

Concerns and Cautions

Meclizine hydrochloride is known to cause birth defects in experimental animals and thus should not be used in pregnant pets.

Due to its potential to reduce milk production, meclizine hydrochloride should not be given to nursing mothers.

Meclizine hydrochloride should not be given to patients who are at risk for urinary retention.

Meclizine hydrochloride should not be given to patients with a history of heart failure.

Meclizine hydrochloride use may interfere with allergic skin testing in patients undergoing evaluation for inhalant allergies.

Meclizine hydrochloride activity can be expected to be prolonged in patients with liver disease.

Date Published: 1/1/2001
Date Reviewed/Revised: 02/01/2008