Effects of transdermal mirtazapine and oral gabapentin as pre-veterinary visit pharmaceuticals for shelter cats

Abstract

Humane medical handling of fearful felines in the shelter is a challenge for staff. Gabapentin has entered into clinical use to attenuate fear and anxiety in cats during handling, but restraint for pilling can be dangerous for the handler and contribute to fear responses in the cat. Administering pre-veterinary visit pharmaceuticals to cats with minimal stress remains elusive. Transdermal medications, which require minimal handling, may improve compliance. While no transdermal anxiolytics have shown a sufficient pharmacodynamic effect in cats, transdermal mirtazapine has entered into use for appetite stimulation. This double-blinded, placebo-controlled study assessed (1) the effect of transdermal mirtazapine on the amount of gabapentin-laced food ingested, and (2) the effect of gabapentin on signs of fear and anxiety in cats when handled for examination. To test this, 94 healthy shelter cats were randomly assigned to one of five treatment groups. Data collected included the amount of food consumed, estimated gabapentin dose consumed where applicable, and physiologic and behavioral parameters during examination. Cats pre-treated with transdermal placebo consumed significantly less gabapentin-laced food than cats pre-treated with transdermal mirtazapine. While there was a significant inverse relationship between estimated gabapentin dose consumed and heart rate and respiratory rate, the addition of transdermal mirtazapine counteracted these effects. No other significant relationships were found between treatments and the remaining measurements. While pre-treatment transdermal mirtazapine allowed for easier administration of gabapentin, its stimulating effects may have counteracted gabapentin’s anxiolytic effects. Future research should investigate reliable, minimally stressful methods for administering pre-veterinary visit pharmaceuticals to shelter cats.