Effect of gabapentin on ambulatory, direct, systemic arterial blood pressure in apparently healthy cats in the at-home and in-clinic environments

Abstract

Objectives Situational increases in blood pressure (BP) frequently confound the accurate diagnosis of pathological systemic hypertension in cats. The objective of this study was to investigate the effect of gabapentin on direct, ambulatory systolic arterial BP (SBP) in cats in at-home and in-clinic environments. Methods Six adult purpose-bred cats with surgically implanted femoral artery telemetric BP-sensing catheters were administered 100 mg of gabapentin or a placebo orally in two randomized, masked, crossover study phases. In the first, direct BP was measured continuously in undisturbed cats for 24 h before (at-home baseline) and 4 h after administration of study drug. The mean SBP after administration of the drug was compared between treatments. In the second study period, cats were administered gabapentin or placebo 90 mins before transport to a clinic, where direct BP was measured continuously during a simulated veterinary visit that included an indirect BP measurement session. Changes in mean direct SBP relative to the 24-h at-home pre-treatment period were calculated for each of one waiting room and two examination-room periods, and compared between treatments. Concurrent in-clinic direct and indirect SBP measurements were compared within-cat. Data were compared using linear mixed models. Results Direct SBP data from one cat were excluded due to implant failure. There were no differences in at-home or in-clinic SBP between treatment groups, with large inter-individual variability. Cats in both treatment groups experienced in-clinic increases in direct SBP relative to at-home baseline (range 11–50 and 10–52 mmHg in placebo- and gabapentin-treated cats, respectively). Across all visits, direct SBP was 15.6 mmHg higher than indirect SBP ( P <0.001). No effects of treatment on difference between direct and indirect SBP were identified. Conclusions and relevance Significant effects of gabapentin on direct SBP were not identified, though a type II error is possible. Situational increases cannot be excluded in gabapentin-treated cats with high SBP.

Assessment of the effect of gabapentin on blood pressure in cats with and without chronic kidney disease

“…A study assessing the effects of gabapentin in a small number of research cats (n = 5) with surgically placed telemetry devices did not find an effect of gabapentin on systolic BP measured by direct methodology. 25 Interestingly, a subjective difference between the direct and indirect systolic BP (with Doppler measuring lower BP after gabapentin administration) was observed, although given the small number of cats, this was not statistically significant. This piece of information raises the question of whether there might be a perceived effect on BP specific to the Doppler technology, perhaps related to the mechanism of peripheral vasodilation and altered arterial myogenic tone.…”

“…Previous studies have documented that Doppler methodology has inconsistent agreement with direct methods of BP measurement. [25][26][27] However, implantation of telemetry for the gold-standard determination of BP was considered too invasive in this patient population, given the number of cats needed to achieve statistical power. In addition, the clinical question was not related to the 'actual' BP measurement, but rather to determine whether a difference in BP was observed between treatment groups as measured by this particular commonly used device.…”