Maropitant citrate hydrate is a specific neurokinin-1 (NK-1) receptor antagonist that selectively inhibits the production of substance P, a mediator involved in signalling vomiting. Maropitant citrate was therefore originally used to treat vomiting in dogs and cats. Currently, it is also used as an adjunct to visceral analgesia in dogs and cats, and in other species such as horses and birds.
The maximum, minimum, and average concentrations of maropitant achieved at steady state were 375.5 ± 200, 16.8 ± 7.7, and 73.5 ± 45.1 ng/ml, respectively. The terminal elimination half-life was 11.6 ± 1.4 hr, and the accumulation index was 1.3 ± 0.07. Heart rate decreased between Day 1 and Day 5 (p = .005), with three horses having heart rates of 20 beats per minute and atrioventricular block on Day 5. Pharmacokinetics of repeated maropitant administration suggests the drug could be considered for use in healthy horses.
Veterinary Drugs and Treatments
Maropitant citrate injectable solution is indicated for the prevention
and treatment of acute vomiting in dogs; maropitant citrate
tablets are indicated for the prevention of acute vomiting and the
prevention of vomiting due to motion sickness in dogs. Both are
also used extra-label in cats.
