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Evaluation of transdermal fentanyl patches for analgesia in cats undergoing onychectomy

Joanne N. Franks DVM1,2, Harry W. Boothe DVM, MS, DACVS3, Lathrop Taylor PhD4, Sue Geller PhD5, Gwendolyn L. Carroll MS, DVM, DACVA6, Victoria Cracas DVM7, and Dawn M. Boothe DVM, PhD, DACVIM, DACVCP8
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  • 1 Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, Texas A&M University, College Station, TX 77843.
  • | 2 Present address: Dallas Veterinary Surgical Center, 4444 Trinity Mills Rd, Ste 203, Dallas, TX 75287-7003
  • | 3 Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, Texas A&M University, College Station, TX 77843.
  • | 4 Department of Veterinary Anatomy and Public Health, College of Veterinary Medicine, Texas A&M University, College Station, TX 77843.
  • | 5 Department of Veterinary Anatomy and Public Health, College of Veterinary Medicine, Texas A&M University, College Station, TX 77843.
  • | 6 Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, Texas A&M University, College Station, TX 77843.
  • | 7 Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, Texas A&M University, College Station, TX 77843.
  • | 8 Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine, Texas A&M University, College Station, TX 77843.

Abstract

Objective—To evaluate efficacy and safety of using transdermal fentanyl patches (TFP) for analgesia in cats undergoing onychectomy.

Design—Randomized controlled clinical trial.

Animals—45 client-owned cats weighing ≥ 2.7 kg (5.9 lb) undergoing onychectomy, onychectomy and ovariohysterectomy, or onychectomy and castration.

Procedure—Cats were randomly assigned to be treated with a TFP (25 µg/h) or butorphanol; TFP were applied a minimum of 4 hours before surgery (approx 8 hours prior to extubation). Rectal temperature, heart rate, respiratory rate, force applied by the forelimbs, and serum fentanyl concentration were measured, and temperament, recovery, degree of sedation, severity of pain, severity of lameness, and appetite were scored before and periodically for up to 40 hours after surgery.

Results—Cats treated with a TFP had better recovery scores at 2 of 4 evaluation times, lower sedation scores at 2 of 8 evaluation times, and lower pain scores at 6 of 8 evaluation times, compared with cats treated with butorphanol. Use of a pressure-sensitive mat to evaluate force applied by the forelimbs did not reveal any differences between groups but did reveal a significant difference between preoperative and postoperative values. Mean ± SD serum fentanyl concentrations were 1.56 ± 1.08, 4.85 ± 2.38, 4.87 ± 1.56, and 4.35 ± 2.97 ng/ml approximately 8, 24, 32, and 48 hours, respectively, after TFP placement.

Conclusion and Clinical Relevance—Results suggest that use of a TFP (25 µg/h) for postoperative analgesia in cats undergoing onychectomy with or without surgical sterilization is safe and effective. (J Am Vet Med Assoc 2000;217:1013–1020)

Abstract

Objective—To evaluate efficacy and safety of using transdermal fentanyl patches (TFP) for analgesia in cats undergoing onychectomy.

Design—Randomized controlled clinical trial.

Animals—45 client-owned cats weighing ≥ 2.7 kg (5.9 lb) undergoing onychectomy, onychectomy and ovariohysterectomy, or onychectomy and castration.

Procedure—Cats were randomly assigned to be treated with a TFP (25 µg/h) or butorphanol; TFP were applied a minimum of 4 hours before surgery (approx 8 hours prior to extubation). Rectal temperature, heart rate, respiratory rate, force applied by the forelimbs, and serum fentanyl concentration were measured, and temperament, recovery, degree of sedation, severity of pain, severity of lameness, and appetite were scored before and periodically for up to 40 hours after surgery.

Results—Cats treated with a TFP had better recovery scores at 2 of 4 evaluation times, lower sedation scores at 2 of 8 evaluation times, and lower pain scores at 6 of 8 evaluation times, compared with cats treated with butorphanol. Use of a pressure-sensitive mat to evaluate force applied by the forelimbs did not reveal any differences between groups but did reveal a significant difference between preoperative and postoperative values. Mean ± SD serum fentanyl concentrations were 1.56 ± 1.08, 4.85 ± 2.38, 4.87 ± 1.56, and 4.35 ± 2.97 ng/ml approximately 8, 24, 32, and 48 hours, respectively, after TFP placement.

Conclusion and Clinical Relevance—Results suggest that use of a TFP (25 µg/h) for postoperative analgesia in cats undergoing onychectomy with or without surgical sterilization is safe and effective. (J Am Vet Med Assoc 2000;217:1013–1020)