Abstract

Orally administered anesthetic agents have been used in a variety of species including domestic goats,⁷ dogs,⁶ and cats,⁸ as well as several exotic felid species,³ bears,^2,4-6 and nonhuman primates¹. Although successful sedation has been reported with oral narcotic drugs in nonhuman primates, due to the potential hazard to personnel and animals, the current study examined the effectiveness of a nonnarcotic drug combination (detomidine and ketamine).

Dosages were calculated at 0.5 mg/kg detomidine (Dormosedan; Pfizer Animal Health, Pfizer Inc., West Chester, PA, USA) and 10 mg/kg ketamine (Vetamine; Schering-Plough Animal Health, Union, NJ, USA) based on estimated body weight at the time of induction. Some animals were also given 0.4 mg/kg metoclopramide and 0.2 mg/kg diazepam orally approximately 90–120 prior to induction to reduce anxiety and prevent emesis. Drugs were administered by keeper staff using husbandry training techniques. Success of administration was estimated by the keeper.

Seven mandrill baboons (Mandrillus sphinx) were given an average of 0.44 mg/kg detomidine and 10.2 mg/kg ketamine orally. Partial administration occurred in four of seven animals. Mean time for initial sedation was 15 min (± 7 min). Animals receiving complete doses were more sedated at earlier times (10 ± 4.5 min). Although none of the seven animals became laterally recumbent with the oral drugs alone, they showed only minimal to moderate response when hand-injected or darted with supplemental drugs (mean time to lateral recumbency = 33.8 ± 12.9 min). All seven animals required supplemental drugs for safe handling. Anesthetic induction and overall anesthetic ratings were good to excellent in all seven cases with only one animal experiencing significant complications (hypothermia/apnea during recovery from prolonged procedure).

Oral detomidine and ketamine were administered to six lowland gorillas (Gorilla gorilla) for anesthetic induction. The average dose was 0.32 mg/kg detomidine and 9.6 mg/kg ketamine orally. Lateral recumbency was achieved at 17 min in the one animal that received a complete dose (0.3 mg/kg detomidine + 9.4 mg/kg ketamine PO). Supplemental tiletamine-zolazepam HCl (0.94 mg/kg IM, Telazol, Fort Dodge Animal Health, Fort Dodge, IA, USA) was administered via dart to ensure safe handling with no visible reaction. The other five animals receiving partial doses showed initial effects at a mean time of 15 min ± 5 min). These animals required supplemental Telazol IM to induce lateral recumbency. Ratings for induction were fair to excellent and appeared to be correlated with estimated amount of oral drugs received and relative level of sedation. In all cases, animals had only mild to moderate response to darting with no screaming or charging. One of the six gorillas had significant complications during the procedure including regurgitation and difficulty maintaining an adequate plane of anesthesia, requiring supplemental injectable drugs.

Subjectively, inductions were judged to be less stressful based on behavior of the individual being sedated and other members of the troop. Although animals being anesthetized were separated, all procedures were performed in the presence of the troop. Decreased screaming, charging, and other stress behaviors were observed in contrast to previous immobilizations using darting equipment.

This preliminary data suggests that orally delivered detomidine and ketamine can be an effective method for sedating nonhuman primates. Administration of supplemental anesthetic drugs is required to achieve complete immobilization for safe handling of these animals.

Acknowledgments

The authors wish to thank Kerri Bolling, Lidia Castro, Eileen McKee, and Carmen Peccie for excellent technical assistance in performing these procedures; Nancy Pratt, Connie Philipp, Barb Weber, Chris Breder, and the primate keepers of Disney’s Animal Kingdom for their support and participation in this study.

Literature Cited

1.  Kearns KS, Ramsay EC, Swenson B. Oral Anesthetic Induction of Chimpanzees (Pan troglodytes) with droperidol and carfentanil citrate. In: Proceedings from Annu Meet Am Assoc Zoo Vet. Puerto Vallerta, Mexico: 1996:401–403.

2.  Mortenson J, Bechert U. Carfentanil citrate as an oral anesthetic agent for brown bears (Ursus arctos). In: Proceedings from Annu Meet Am Assoc Zoo Vet. Puerto Vallerta, Mexico: 1996:518–528.

3.  Ramsay EC, Grove D, Miller M, Schumacher J. Immobilization of felids using oral detomidine and ketamine. In: Proceedings from Annu Meet Am Assoc Zoo Vet. Columbus, OH: 1999:47–48.

4.  Ramsay EC, Sleeman JM, Clyde VL, Gieser D. Immobilization of bears using orally administered carfentanil citrate. In: Proceedings from Annu Meet Am Assoc Zoo Vet. Pittsburgh, PA: 1994:214.

5.  Ramsay EC, Sleeman JM, Clyde VL. Immobilization of black bears (Ursus americanus) with orally administered carfentanil citrate. J Wildl Dis. 1995;31:391–393.

6.  Ramsay EC, Wetzel RW. Comparison of five regimens for oral administration of medication to induce sedation in dogs prior to euthanasia. J Am Vet Med Assoc. 1988;213:240–242.

7.  Sleeman J, Ramsay E. Preliminary investigations in the use of orally administered carfentanil citrate and detomidine to immobilize domestic goats (Capra hircus). In: Proceedings from Annu Meet Am Assoc Zoo Vet. East Lansing, MI: 1995:271–272.

8.  Wetzel RW, Ramsay EC. Comparison of four regimens for intraoral administration of medication to induce sedation in cats prior to euthanasia. J Am Vet Med Assoc. 1998;13:243–245.