The Effectiveness of Cyproheptadine as a Treatment Option for Cats with Eosinophilic Airway Inflammation

PICO question: In cats with eosinophilic airway inflammation does cyproheptadine compared with no treatment result in a reduction in severity of clinical signs? Category of research: Treatment. Number and type of study designs reviewed: Four studies were evaluated: the first was a randomised, blinded, placebo-controlled, crossover study, the second was a randomised crossover study, the third was a non-randomised, controlled study, and the fourth a non-randomised, controlled study. Strength of evidence: Moderate. Outcomes reported: In two of the four studies it was found that cyproheptadine was not useful in resolving the symptoms of feline airway inflammation. The third study showed that the concentration of cyproheptadine that completely blocked contractile effects of serotonin did not successfully cause a significant effect on contraction caused by muscarinic stimulation. The fourth study provided evidence that cyproheptadine could reduce serotonin-induced bronchoconstriction. Conclusion: There is no current evidence to support that cyproheptadine monotherapy has any immediate benefit over no treatment for feline eosinophilic airway inflammation, and its use is not supported for this indication. How to apply this evidence in practice The application of evidence into practice should take into account multiple factors, not limited to: individual clinical expertise, patient's circumstances and owners' values, country, location or clinic where you work, the individual case in front of you, the availability of therapies and resources.Knowledge Summaries are a resource to help reinforce or inform decision making. They do not override the responsibility or judgement of the practitioner to do what is best for the animal in their care.