Dogs Get Vomiting Drug of Their Own: Cerenia Works in Emetic Center of the Brain to Suppress Vomitin
A drug that prevents and treats canine vomiting triggered by both pathways was approved by the Food and Drug Administration (FDA) on Feb. 28, 2007, and tested by 40 veterinary clinics in the United States. Professionals say that Cerenia (maropitant citrate), manufactured by Pfizer Animal Health has a unique delivery mechanism because it works within the emetic (vomiting) center of the brain. It will be available this summer. Cost of the drug and an exact release date were unavailable at press time.
“We’ve never had an FDA-approved drug [to treat vomiting in] dogs,” said Lynn Buzhardt, DVM, who conducted two trials on Cerenia in 2002 and 2004 at The Animal Center in Louisiana. “As veterinarians, we want to prevent illness where we can – which Cerenia does with motion sickness – and treat illness when we see it, which Cerenia does with acute illness.”
Unlike existing products, which address one of two internal pathways that signal vomiting, Cerenia works on both, said Ann Trettien, DVM, manager of Pfizer’s companion animal operations group. It accomplishes this by binding to the NK1 receptor in the emetic center of the brain to block Substance P from adhering to it. The connection of the transmitter and receptor causes vomiting, regardless of whether the problem originates in the central or peripheral pathway of the brain.
Vomiting caused by the central pathway is attributed to gastritis, parvovirus, or emotions that affect higher brain centers like anxiety or fear while vomiting traced to the peripheral pathway is linked to organ failures, toxins in the blood stream, and geriatric ailments, Trettien said. If a gastrointestinal obstruction is suspected, doctors may consider Cerenia as a tool while considering surgery, she added.
Clinical trials on 577 client-owned dogs showed that Cerenia is safe for patients, ages 16 weeks and older, to treat one of the most common ailments presented to veterinarians. Pfizer estimates that veterinarians see an average of 30 vomiting cases per month or 2.8 million cases per year. In trials, the drug had a 95 percent efficacy with prevention (for motion sickness) and an 80 percent efficacy rate with the treatment of vomiting caused by acute illness. Consumer research from Pfizer shows that one out of six dogs suffers from motion sickness though many clients do not report the problem, Trettien said.
In the past, veterinarians have prescribed human drugs – like tranquilizers, metoclopramide, and zofran – to treat or prevent vomiting.
“Human drugs [that we have used in the past] don’t always meet our needs as specifically as we’d like,” Buzhardt explained.
Cerenia, which can be delivered by injection or pill form, will reduce distress associated with vomiting while doctors pursue diagnoses, Trettien said.
Anthony Carr, DVM, DACVIM, of Western College of Veterinary Medicine, has followed Cerenia research and intends to use it after a diagnosis has been established.
“I don’t think this drug should be given out to treat a symptom until an etiological diagnosis is made,” he said. He explained that while drugs like Cerenia are helpful in limiting dehydration for chemotherapy patients, prescribing it before a patient has been diagnosed is inappropriate.
Buzhardt disagreed. She said that giving Cerenia to dogs while she worked up a diagnosis shortened recovery time by preventing the secondary effects of vomiting, such as electrolyte imbalance, loss of appetite, and esophagitis.
“Cerenia expedites the recovery process and it decreases discomfort for dogs and owner anxiety,” said Buzhardt, whose clinic has been used by the FDA to test drugs for the past 27 years.