Changes in the stress markers cortisol and glucose before and during intradermal testing in cats after single administration of pre-appointment gabapentin

Objectives Intradermal allergy testing can be difficult to interpret in cats. Studies have shown that intradermal testing leads to elevations in blood cortisol, which may be an explanation for weak wheal reactions in cats. The primary objective of this study was to determine whether utilizing pre-appointment gabapentin will alter stress before and during intradermal testing, as determined by cortisol/glucose concentrations. Methods This was a randomized, single-blinded, crossover clinical trial of 16 privately owned healthy cats. Cats were scheduled two veterinary visits and randomly assigned to receive either gabapentin (25.0-30.5 mg/kg) or no treatment prior to the first visit and the opposite treatment prior to the second visit. Blood samples were obtained to measure cortisol/glucose concentrations at three time points: directly after physical examination; directly after sedation; and 10 mins after the second blood sample. A limited intradermal test was performed after the second blood sample. The primary author also recorded which visit they believed gabapentin was administered with low/high confidence. A non-blinded owner assessment survey documenting stress levels in their cats was also obtained. Results Mean cortisol concentrations were calculated to be 0.30 mu g/dl lower in the gabapentin group but this reduction was not significant. Mean glucose concentrations were calculated to be 18 mg/dl higher in the gabapentin group. Gabapentin had no negative effect on intradermal histamine readings. The author was able to correctly identify when 14/16 cats received gabapentin. Non-blinded owners (n = 14/16) believed their cats were less stressed when gabapentin was administered. Conclusions and relevance Gabapentin did not significantly decrease cortisol/glucose concentrations. A sedative effect, rather than suppression of the pituitary-adrenocortical axis, may have led to the lower stress assessment. It is unlikely that pre-appointment gabapentin will alter intradermal testing in a majority of cats. This study supports recent clinical trials demonstrating that administration of gabapentin can lower veterinarian/owner assessment of stress in cats.