Pre-Hospital Sedation of Cats

Improving the feline experience at the time of the veterinary visit and time surrounding that visit is imperative in cats. Cats, however, can be a far more challenging species to judge behaviorally as they are often less interactive and more elusive than dogs. In stressful situations, such as the unexpected car ride or annual exam, the fearful and anxious cat may display aggressive behaviors such as biting and swatting, which can cause self trauma, harm to the owner, and/or harm to the veterinary staff. The therapies included in this brief article are meant to reduce anxiety and arousal in cats, with the goal of enhancing the entire veterinary visit experience for all involved. The author encourages the use of the included pharmacologic interventions IN TANDEM with other practices such as dedicated cat-friendly environments and “Fear Free” handling techniques (e.g. body wraps, feline pheromones, etc.). Whenever possible, a full physical exam should be done before prescribing pre-hospital sedatives.

Gabapentin binds to calcium a₂-d receptors in the dorsal horn of the spinal cord and forebrain, having an inhibitory effect.^1,2,3,4 It has long-term historical use as an adjunctive analgesic in both humans and animals^1,4,5; however, its antiepileptic properties are likely responsible for sedation. In the acute setting, sedation following gabapentin administration is often profound. This was highlighted in a recent study in which both owners and veterinarians observed stress reduction, improved compliance, and less aggression in cats that received gabapentin 90 minutes prior to transport to the veterinary hospital.⁶ Owners need to be made aware that their pet will often appear considerably more sedate at home. Cats should be more closely supervised on stairs or when jumping place to place given ataxia that may occur following administration. Dosing recommendations and timelines are proposed below (Table 1).⁶ Gabapentin is an ideal agent to use alone, especially in those cats that may be older and have more chronic pain states, as the drug provides sedation and analgesia without undesirable adverse effects.^4,5,6 It can be used in combination with the other included agents in cats needing additional sedation.

Trazodone is classified as a serotonin receptor antagonist and reuptake inhibitor (SARI),^1,7,8 with historical use in anxious dogs. Two recent studies in two different feline populations – 1) a research setting⁷ and 2) client-owned cats in the clinical setting⁸ – indicated that trazodone was well tolerated and resulted in cats with improved behavior and tractability scores. Of note in the clinical study was that owners, too, observed key behavioral improvements following trazodone administration in comparison to placebo.⁸ In laboratory cats, trazodone caused no remarkable changes to physical exam and/or laboratory values⁷ adding to its margin of safety in older, potentially debilitated patients. Pharmacokinetic data have not been measured, but studies indicate peak sedation within 1-3 hours after dosing (Table 1).

Acepromazine is part of the phenothiazine class of sedatives and has widespread use within the veterinary world primarily during the perianesthetic period. Acepromazine elicits behavior-modifying effects primarily by drug binding and blockade of dopamine receptors in the basal ganglia and limbic system.^1,2 The drug exists for veterinary use in two forms – oral and injectable. The injectable form, when administered oral transmucosally (OTM) offers very reliable moderate to marked sedation in cats within 20-30 minutes. With this route of administration, the dose closely follows recommended intramuscular (IM) dosing (Table 1).^1,2,4 In the aggressive or fearful cat, this drug is best given 30-60 minutes prior to the hospital visit with administration guidelines similar to OTM buprenorphine (effects are most profound following absorption from the oral mucosa). Given a higher prevalence of heart disease in cats, acepromazine should be avoided in any cat with a heart murmur of unknown origin and cats with known hypertrophic cardiomyopathy (HCM) as safer alternatives exist and the effects of acepromazine are NOT reversible. Other contraindications include disease states that would deter one from using acepromazine in an anesthetic protocol.

In considering what pharmacologic intervention to start with, it is recommended to move in a stepwise process. Gabapentin and trazadone are recommended as first line choices in ameliorating feline anxiety and aggression as they have both been shown to be safe and effective options to improve feline veterinary visits. They can be given independently (start with one, as you can always add more if needed) or together in those cats requiring increased sedation. All of these oral therapies can be combined with standard anesthetic protocols; however, when using acepromazine OTM, any additional doses of injectable acepromazine should be dose reduced. As a final reminder, all of these therapies should be combined with cat-friendly practices and low-stress handling techniques.

Table 1: Dosing and timeline of administration for sedative agents. Timing regimen should be adjusted based on cat’s appointment time.

References:

1. Lumb and Jones’ Veterinary Anesthesia, 4^th Thurman JC, Tranquilli WJ, Benson GJ. Baltimore: Williams & Wilkins; 2007.
2. Essentials of Small Animal Anesthesia and Analgesia, 2^nd Grimm KA, Tranquilli WJ, Lamont LA. Wiley-Blackwell; 2011.
3. Lamont LA. Adjunctive Analgesic Therapy in Veterinary Medicine. Vet Clin: SA Prac 2008;38:1187-1203.
4. Dyson DH. Analgesia and Chemical Restraint for the Emergent Veterinary Patient. Vet Clin: SA Prac 2008;38:1329-1352.
5. Pypendop BH, Siao KT, Ilkiw JE. Thermal antinociceptive effect of orally administered gabapentin in healthy cats. A J Vet Res 2010;71:1027-1032.
6. Van Haaften KA et al. Effects of a single preappointment dose of gabapentinon signs of stress in cats during transportation and veterinary examination. J Am Vet Med Assoc 2017;251(10):1175-1181.
7. Orlando JM et al. Use of oral trazodone for sedation in cats: a pilot study. J Feline Med Surg 2016;18(6):476-482.
8. Stevens BJ et al. Efficacy of a single dose of trazodone hydrochloride given to cats prior to veterinary visits to reduce signs of transport- and examination-related anxiety. J Am Vet Med Assoc 2016;249(2):202-207.