Ondansetron

Ondansetron In Dogs & Cats: Uses, Dosage and Side Effects

Overview

• This medication exerts strong antiemetic effects by acting on both the gastrointestinal (GI) tract and the chemoreceptor trigger zone.
• It was originally developed for and is especially effective in preventing vomiting triggered by chemotherapy drugs.
• Its mechanism of action also makes it a suitable option for managing vomiting caused by peripheral emetogenic stimuli, such as GI tract irritation.

Uses of Ondansetron

• Treatment of nausea and vomiting in patients whose symptoms remain uncontrolled by other drugs like maropitant and metoclopramide.
• While similar drugs such as dolasetron, granisetron, palonosetron, and tropisetron exist, their use in companion animals is not well-documented.
• The oral bioavailability of this medication is generally regarded as low.
• However, when administered subcutaneously to healthy cats, ondansetron is more bioavailable and leads to a longer duration of exposure compared to oral administration.

Dose of Ondansetron in Dogs and Cats

Dogs, Cats:

• All uses: 0.5 mg/kg i.v. loading dose followed by 0.5 mg/kg/h infusion for 6 hours or 0.5–1 mg/kg p.o. q12–24h.

Side Effects of Ondansetron in Dogs and Cats

• Well tolerated.
• In humans, constipation, headaches, occasional alterations in liver enzymes and, rarely, hypersensitivity reactions have been reported.

Contraindications of Ondansetron in Dogs and Cats

• Intestinal obstruction.

Some Notes:

• Ondansetron may reduce the effectiveness of tramadol and so the dose of tramadol may need to be increased.