Gabapentin

Gabapentin is a gabapentinoid used extra-label in veterinary medicine for selected neuropathic pain states, adjunctive seizure treatment and situational anxiety. A particularly common application is reduction of transport- or examination-related stress in cats. Its clinical effect depends on the indication, and evidence is stronger for some uses than for others.

Group

Gabapentinoid

Mechanism of Action

Gabapentin binds the alpha2delta auxiliary subunit of voltage-gated calcium channels in neurons. This alters channel trafficking and calcium-dependent neurotransmitter release, reducing excitatory signaling in sensitized pain pathways and neuronal networks. These effects contribute to its analgesic and anticonvulsant actions. Despite its structural relationship to GABA, it does not act as a direct GABA-receptor agonist.

Dose Rates

Dog

Use / stage	Dose	Route	Schedule	Instructions
Adjunctive epilepsy	10–20 mg/kg	PO	Every 8 h
Neuropathic pain — Initial	5–15 mg/kg	PO	Every 12 h
Neuropathic pain — Maintenance	40 mg/kg	PO	Every 8–12 h	Upper reported escalation, reached gradually only if needed and tolerated.
Behavior adjunct	5–30 mg/kg	PO	Every 8 h	Up to three times daily; start low and change dose about 7 days apart.
Situational anxiety	30–60 mg/kg	PO	Once	1–2 hours before the anticipated event.
Chronic pain adjunct	3 mg/kg	PO	Every 24 h
Chronic pain adjunct	1.25–10 mg/kg	PO	Every 24 h

Cat

Use / stage	Dose	Route	Schedule	Instructions
Adjunctive epilepsy	5–10 mg/kg	PO	Every 12 h
Adjunctive epilepsy	20 mg/kg	PO	Every 8–12 h	Escalation in selected cats.
Neuropathic pain	5–10 mg/kg	PO	Every 12 h
Situational anxiety	100 mg/animal	PO	Once	Source fixed regimen, approximately 90 minutes before the event; peak effects 2–3 hours. Individualize in small, frail or renally impaired cats.
Situational anxiety	20–30 mg/kg	PO	Once	Weight-based alternative; do not add to the fixed-dose regimen.
Chronic pain adjunct	3 mg/kg	PO	Every 24 h
Chronic pain adjunct	1.25–10 mg/kg	PO	Every 24 h
Neuropathic pain	2.5–5 mg/kg	PO	Every 12 h	Titrate to effect and sedation; reduce in renal insufficiency and taper gradually.
Refractory seizures adjunct	5–10 mg/kg	PO	Every 8–12 h
Refractory seizures adjunct	10–30 mg/kg	PO	Every 8–12 h

Horse

Use / stage	Dose	Route	Schedule	Instructions
Neuropathic pain	2.5 mg/kg	PO	Every 12 h
Laminitis adjunct	2.5 mg/kg	PO	Every 8 h
Laminitis adjunct	2.5 mg/kg	PO	Every 12 h
Laminitis adjunct	2.5 mg/kg	PO	Every 24 h
Laminitis adjunct	10 mg/kg	PO	Every 8–12 h	Higher studied exposure; clinical efficacy remains uncertain and oral absorption is low.

Indications

Reduction of transport- and veterinary-visit-associated fear or stress in cats.
Adjunctive management of selected neuropathic pain in dogs and cats, including some dogs with syringomyelia-associated pain; efficacy varies with the condition.
Adjunctive treatment of refractory seizure disorders in selected dogs, with a limited veterinary evidence base.
Adjunctive treatment of selected situational anxiety or fear-related disorders in dogs, supported by more limited evidence than feline pre-visit use.

Contraindications

Adjust for impaired clearance; avoid abrupt withdrawal after sustained treatment.
Avoid xylitol-containing formulations in dogs.

Interactions

Antacids reduce absorption; separate by 2 hours.
Sedatives and anesthetics may require lower doses.

Adverse effects

Sedation and ataxia
GI upset at high doses

Preparations

Preparation	Form	Strength	Route
Gabapentin 100 mg	Tablet	100 mg / tablet	PO
Gabapentin 300 mg	Tablet	300 mg / tablet	PO
Gabapentin 400 mg	Tablet	400 mg / tablet	PO
Gabapentin 600 mg	Tablet	600 mg / tablet	PO
Gabapentin 800 mg	Tablet	800 mg / tablet	PO
Gabapentin 100 mg capsule	Capsule	100 mg / capsule	PO
Gabapentin 300 mg capsule	Capsule	300 mg / capsule	PO
Gabapentin 400 mg capsule	Capsule	400 mg / capsule	PO

Monitoring and Administration

Monitor sedation and functional benefit; evidence for pain varies by condition. Taper prolonged therapy.

Avoid xylitol-containing oral products in dogs. Transdermal delivery in cats has not provided reliable therapeutic exposure.

A 50 mg/mL human oral solution is described, but xylitol-containing products are not included as routine canine preparations. Extended-release Gralise is not interchangeable with these immediate-release regimens.