Influence of gabapentin on the degree of sedation, physiological variables and propofol dosage in cats premedicated with acepromazine and methadone: a randomized, prospective, blinded, clinical study

This study evaluated the influence of gabapentin on sedation, propofol dosage, and physiological variables in cats premedicated with acepromazine and methadone. Thirty-four cats were randomly assigned to receive 100 mg of oral gabapentin (Gabapentin group) or placebo (Control group) 100 min before intramuscular premedication with acepromazine (0.05 mg/kg) plus methadone (0.3 mg/kg). Variables recorded included sedation, using the Dynamic Interactive Visual Analog Scale (DIVAS, range 0-100 mm) and a Numeric Descriptive Scale (NDS, range 0-14), heart rate, respiratory rate and Doppler systolic arterial pressure (SAP). All variables were measured before (T0), 100 min after administration of gabapentin or placebo (T1), and 30 min after premedication (T2). Physiological variables were also recorded after anesthetic induction with propofol (T3). At T2, NDS scores were higher in Gabapentin than the Control group [median (interquartile range): 4 (2-5) versus 2 (1-4), p = 0.028], whereas DIVAS scores were not significantly different [Control: 9 (4-13); Gabapentin: 12 (5-32)]. Despite the significant difference between groups in NDS scores, overall sedation scores were mild at T1 and T2 regardless of gabapentin administration. The propofol dosage did not differ between groups. The most concerning adverse effect was arterial hypotension (SAP < 90 mmHg), recorded only at T3 in 71% of cats in the Control group and 100% in the Gabapentin group, without significant difference between groups. Administration of gabapentin before premedication with acepromazine and methadone in healthy cats did not result in a clinically significant influence on sedation levels, physiological variables, or propofol dosage required for anesthesia induction.