Gabapentin as a sedative/anxiolytic prior to ultrasonography in cats
Gabepentin is an enormously useful drug to facilitate ultrasonography in cats. I’m sure most of you are aware of this by now but it’s worth publicising a little more because, to get best effect, the use of gabapentin needs to be planned in advance of the day of scanning.
J Am Vet Med Assoc. 2017 Nov 15;251(10):1175-1181. doi: 10.2460/javma.251.10.1175.
Effects of a single preappointment dose of gabapentin on signs of stress in cats during transportation and veterinary examination.
van Haaften KA, Forsythe LRE, Stelow EA, Bain MJ.
Those authors asked owners to administer a 100mg capsule of gabapentin to their pet 90 minutes before transport to the clinic. Their conclusions:
‘Owners’ perception of stress in their cats is a primary reason for failing to seek veterinary care. Results of this study suggested that gabapentin is a safe and effective treatment for cats to help reduce stress and aggression and increase compliance for transportation and veterinary examination’
Although unlicensed, gabapentin is widely considered to be safe for cats.
J Vet Intern Med. 2018 Nov;32(6):1996-2002. doi: 10.1111/jvim.15313. Epub 2018 Oct 11.
The pharmacokinetics of gabapentin in cats.
Adrian D1,2, Papich MG3, Baynes R4, Stafford E2,4,5, Lascelles BDX1,2,6,7.
J Feline Med Surg. 2018 Jun;20(6):535-543. doi: 10.1177/1098612X17719399. Epub 2017 Jul 18.
Use of single-dose oral gabapentin to attenuate fear responses in cage-trap confined community cats: a double-blind, placebo-controlled field trial.
Pankratz KE1, Ferris KK1, Griffith EH2, Sherman BL1.
Mild adverse effects such as ataxia, hypersalivation, and vomiting have been reported. All effects resolved within 8 hours after gabapentin administration in the JVIM, JFMS and JAVMA papers. All 53 cats in the JFMS paper underwent general anaesthesia uneventfully after gabapentin administration.
Gabapentin is widely considered to be safe to use in the presence of cardiovascular disease and not to significantly affect echocardiographic findings.
‘Gabapentin produces no known cardiovascular effects, direct or indirect, in cats.’
Although this does not appear to have been verified in a prospective, peer-reviewed paper to the best of our knowledge. Generally speaking, our feeling is that cats with uncontrolled, severe dyspnoea can usually be dealt with effectively without full echocardiography (essentially the important issue initially is just to decide whether CHF is the cause of dyspnoea) and thus probably don’t need or justify sedation. Please talk to us if in doubt. Cats presenting with other scenarios requiring echocardiography, on the other hand (murmur, stable heart disease, syncope) often do need full echocardiography for accurate diagnosis, treatment and prognosis. For those guys, if you’re going to have to sedate then gabapentin is almost certainly safer and less likely to affect findings than any of the alternatives. And, indeed, safer than trying to struggle with a nervous, un-medicated cat.
Bodyweight of cats in the JAVMA study ranged from 3.4-7.7Kg. Owners of the two lightest cats reported marked sedation after return home. The authors suggest:
‘For cats with a body weight close to the mean in this study (5.15 kg), a gabapentin dose of 100 mg (approx 20 mg/kg) appeared to result in the best balance of clinical effect with adverse effects. However, pharmacokinetics data suggest a wide range of individual variation in peak plasma concentration with oral gabapentin administration in cats; consequently, doses may need to be tailored to the individual patient’
In the JFMS paper doses up to 47mg/Kg were administered without serious adverse effects.
In our experience gabapentin is not always completely effective in allowing us to scan cats without further sedation. Thus it’s worth factoring in the cat’s temperament to your choice of dose. A completely unhandleable, dangerous-to-handle cat would justify a dose of 30-35mg/kg whereas a wriggly, nervous but not-as-far-as-we-know-aggressive cat would be OK at 20mg/Kg.
Gabapentin apparently has a mild taste: many cats will voluntarily consume it when mixed with food. I cant find a specific scientific reference to document the effect of opening the capsule and mixing the content with food. However, anecdotally, people certainly do this and it seems to be safe and effective.
Liquid formulations of gabapentin are available in the UK. At least some of these contain xylitol which should not be used in dogs. In cats, however, xylitol does not appear to be dangerous.
Apparently, in the UK chicken-flavoured gabapentin paste is available from Bova
In the JFMS paper a liquid formulation was administered in combination with flavouring by syringe through the bars of cage to feral cats.