© 2003-17 Susan K. Mikota DVM and Donald C. Plumb, Pharm.D. Published by
Elephant Care International
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CAUTION! Sedative and anesthetic drug dosages for African elephants often vary from those for Asian elephants. Do not assume that the recommendations for one species can be applied to the other. Significant variation may also occur between individual elephants. Higher doses may be needed in wild or excited animals. Unless otherwise specified, doses refer to captive elephants. The information provided here should be used as a guideline only. Consultation with experienced colleagues is advised.
SPECIAL NOTE REGARDING CARFENTANIL: Opioid narcotics elevate blood pressure and have been implicated in the etiology of pink foam syndrome in wild African elephants. This emergency situation can be fatal. The syndrome manifests as pink froth from the trunk and is caused by pulmonary edema and capillary bleeding. Several authors recommend that azaperone be combined with opioid narcotics to counteract these hypertensive effects (see Hattingh and Knox, 1994 below). Also see azaperone monograph.
a) African elephants: 0.0021 mg/kg; supplement with 0.0005 mg/kg if needed; agitated or aggressive animals may require higher doses; reverse with 0.08 mg/kg naltrexone or nalmefene (Kreeger et.al. 2002).
b) For wild African elephants the following doses of carfentanil are recommended:
Calves with shoulder heights of 90-115 cm: 1 mg
Calves with shoulder heights of 116-114 cm: 3 mg
Calves with shoulder heights of 141-165 cm: 5 mg
Calves with shoulder heights of 166-200 cm: 7 mg
Adult females: 10 mg
Adult males: 13 mg
These doses can be reduced by 25% for elephants in captivity (Raath, 1999).
c) A 5000 kg Asian elephant was given 10 mg carfentanil for surgical curettage of a foot abscess (Honeyman et.al. 1998).
d) Thirty-seven wild African elephants were immobilized as follows: Calves (4-6 years; n=4) were immobilized with 1 mg carfentanil and adults with 3 mg carfentanil mixed with 1500 IU of hyaluronidase. All animals were reversed with naltrexone at a rate of 100 mg for every mg of carfentanil used. For 15 elephants, mean minutes elapsed for initial effect of standing still, recumbency, and recovery following reversal were 5.0 ±1.6, 10.7±3.9, and 5.9±3.9 respectively (Karesh et.al. 1997).
e) Asian elephants: 0.002-0.004 mg/kg (total dose 5-12 mg); African elephants: 0.002 mg/kg (total dose 3-12 mg) (Fowler, 1995).
f) 2.4 µg/kg IM was given to captive juvenile African elephants. See abstract below (Schumacher, et.al. 1995).
g) Carfentanil in combination with azaperone to reduce blood pressure. See abstract below (Hattingh et.al. 1994).
h) For African elephants (wild vs. captive not specified): 1-5 mg for juveniles (1-5 years); 6-8 mg for adult females; 9-10 mg for adult males (Kock et.al. 1993).
i) One African elephant weighing 900 kg was immobilized with 2.3 µg/kg carfentanil IM (1.8 mg total dose), intubated and maintained on halothane and reversed uneventfully with 36 mg nalmefene IV and 36 mg SC. Another African elephant weighing 1,110 kg was immobilized at the same dosage (2.7 mg total dose), maintained on halothane and reversed with 90 mg nalmefene IV and 90 mg SC (Welsch et.al. 1989).
j) Sixteen African elephants were immobilized with single IM injections of 2.3 ± 0.03 µg/kg IM carfentanil. See abstract below (Jacobson et.al. 1988).
k) Fourteen African elephants were immobilized with etorphine (2.9 ± 0.7 µg/kg ) or carfentanil (2.0 ± 0.2 µg/kg) and physiological effects compared. See abstract below. (Jacobson et.al, 1987).
a) Kreeger,T.J., Arnemo,J.M., and Raath,J.P., 2002. Handbook of wildlife chemical immobilization. Wildlife Pharmaceuticals Inc., Fort Collins, Colorado, U.S.A., pp.183-184.
b) Raath,J.P. 1999. Relocation of African elephants. In: Fowler,M.E. and Miller,R.E. (Editors), Zoo and Wild Animal Medicine: Current Therapy 4. W.B. Saunders, Philadelphia, PA, USA pp. 525-533
c) Honeyman,V.L., Cooper,R.M., and Black,S.R. 1998. A protected contact approach to anesthesia and medical management of an Asian elephant (Elephas maximus). Proceedings AAZV and AAWV Joint Conference. Pages: 338-341
d) Karesh,W.B., Smith,K.H., Smith,F., Atalia,M., Morkel,P., Torres,A., House,C., Braselton,W.E., and Dierenfeld,E.S. 1997. Elephants, buffalo, kob, and rhinoceros: immobilization, telemetry, and health evaluations. Proceedings American Association of Zoo Veterinarians. Pages: 296-230
e) Fowler,M.E., 1995. Elephants. In: Restraint and handling of wild and domestic animals. Iowa State University Press, Ames, Iowa, USA pp. 265-269
f) Schumacher,J., Heard,D.J., Caligiuri,R., Norton,T., and Jacobson,E.R. 1995. Comparative effects of etorphine and carfentanil on cardiopulmonary parameters in juvenile African elephants (Loxodonta africana). Journal of Zoo and Wildlife Medicine 26:(4):503-507
Abstract: Fourteen African elephants (Loxodonta africana) were immobilized with either etorphine hydrochloride (3.2 ± 0.5 µg/kg i.m.) or carfentanil citrate (2.4 µg/kg i.m.). Induction time with etorphine was significantly longer (30 ± 21 min) than with carfentanil (8 ± 2 min). Immediately following immobilization all elephants were placed in lateral recumbency and respiratory rate, heart rate, and rectal body temperature were monitored every 5 min throughout the immobilization period. Arterial blood samples, collected from an auricular artery, were taken 10 min after immobilization and every 15 min thereafter for up to 1 hr. At the first sampling, mean values for arterial blood gas variables for etorphine immobilized elephants were pHa, 7.29 ± 0.03; PaCO2, 53.4 ± 5.2 mmHg; PaO2, 71.8 ± 13.8 mmHg; standard base excess (SBE), -1.6 ± 2.9 mEq/L; and HCO3, 25.7 ± 2.7 mEq/L. After 1 hr of immobilization, mean arterial blood gas values were pHa, 7.32 ± 0.06; PaCO2 , 57.2 ± 9.6 mm Hg; and PaO2 , 53.8 ± 10.5 mm Hg; SBE, 2.7 ± 1.4 mEq/L; and HCO3-, 30.6 ± 1.6 mEq/L.
For carfentanil immobilized elephants, blood gas values at the first time of collection were pHa, 7.28 ± 0.04; PaCO2, 52.1 ± 2.8 mmHg; PaO2, 78.3 ± 14.7 mmHg; SBE, -2.3 ± 24 mEq/L; and HCO3-, 24.3 ± 2.1 mEq/L. Sixty minutes after the first sampling, blood gas values of one elephant were pHa, 7.38; PaCO2, 48.7 mmHg; PaO2, 52 mmHg; SBE, 3.4 mEq/L, and HCO3-, 28.8 mEq/L. Over time there was a progressive decline in arterial PO2 in all elephants. It is concluded that elephants immobilized with either etorphine HCl or carfentanil developed hypoxemia (PaO2 < 60 mmHg) after 30 min of immobilization. It is recommended that the administration of one of these opioid drugs be accompanied by supplemental oxygen, or followed by an inhalant anesthetic in 100% oxygen for prolonged procedures. Diprenorphine or nalmefene reversal was rapid and uneventful in both the etorphine and carfentanil group. No cases of renarcotization were noted. Additional excerpt: All elephants in the etorphine group (n=8) received diprenorphine at a mean dosage of 8.3 ± 1.1 µg/kg IV. Two elephants in the carfentanil group (n=6) were administered diprenorphine at a dosage of 8.9 µg/kg IV and IM. Three elephants in this group received nalmefene hydrochloride. One of the three elephants was given nalmefene 166.7 µg/kg both IV and SC. Two of the three elephants were given nalmefene IV and IM. The dosage was 88.9 µg/kg IV and IM in one elephant and 53.3 µg/kg IV and IM in the other. One elephant in the carfentanil group was administered nalmefene (88.9 µg/kg IV) followed by diprenorphine (8.9 µg/kg IM).
g) Hattingh,J. and Knox,C.M. 1994. Arterial blood pressure in anesthetized African elephants. South African Journal of Wildlife Research 24:(1/2): Abstract: A number of elephants previously captured in the Krueger National Park developed a pink frothy discharge from the external nares. Some of these elephants subsequently died and histopathological examinations indicated severe lung oedema. In view of the current hypothesis that high blood pressure could be a causative factor, arterial blood pressure was measured in elephants immobilized with etorphine alone (n=71) and with etorphine/azaperone (n=109) and with carfentanil/azaperone (n=26) mixtures. Arterial pressure was found to be significantly lower in the groups immobilized with azaperone mixtures than in the group immobilized with etorphine alone (p < 0.05). In addition, no cases of lung oedema were observed in animals immobilized with etorphine/azaperone and carfentanil/azaperone mixtures. It is strongly recommended, therefore, that azaperone be added to immobilization mixtures when elephants are subjected to herding prior to darting. Additional excerpt: all elephants in this study were juveniles 200 to 1300 kg. Group 1 (n=71) was immobilized with 4-8 mg etorphine; group 2 (n=109) was immobilized with 4-8 mg etorphine and 50-90 mg azaperone; and group 3 (n=26) was immobilized with 4-8 mg carfentanil and 50-90 mg azaperone.
h) Kock,R.A., Morkel,P., and Kock,M.D., 1993. Current immobilization procedures used in elephants. In: Fowler,M.E. (Editor), Zoo and Wild Animal Medicine Current Therapy 3. W.B. Saunders Company, Philadelphia, PA, USA pp. 436-441
i) Welsch,B., Jacobson,E.R., Kollias,G.V., Kramer,L., Gardner,H., and Page,C.D. 1989. Tusk extraction in the African elephant (Loxodonta africana). Journal of Zoo and Wildlife Medicine 20:(4):446-453 Abstract: Unilateral dentoalveolar abscesses and/or tusk fractures were identified and tusk extractions performed in seven 3.5-21-yr-old African elephants (Loxodonta africana) of both sexes weighing 650-3,000 kg. Following immobilization with etorphine hydrochloride or carfentanil citrate, six of seven elephants were intubated and maintained on a 1-1.5% halothane in oxygen mixture; one elephant was maintained in lateral recumbency by multiple i.v. injections of etorphine. All elephants were positioned with the affected tusk up. For one elephant, two surgical procedures were required to remove the tusk. In six of seven elephants, the tusks were sectioned transversely and the tusk wall thinned by enlarging the pulp cavity with carbide burs. In those tusks with remaining pulp, the pulp was removed with stainless steel rods and hooks. Next, the tusk was sectioned longitudinally into three or four segments using a wood saw within the pulp chamber. bone gouges, osteotomes, and a mallet were used to free the outer epithelial and alveolar attachments from the tusk. Starting with the smallest segment, the sections were removed using long screwdriver-shaped stainless steel rods. The alveolar chamber was then periodically flushed postsurgically with a dilute organic iodine solution. For six of seven elephants, complete granulation of the alveolar chamber was evident by 4 mo postsurgery; the seventh elephant showed partial healing with granulation tissue at 2 mo following surgery.
j) Jacobson,E.R., Kollias,G.V., Heard,D.J., and Caligiuri,R. 1988. Immobilization of African elephants with carfentanil and antagonism with nalmefene and diprenorphine. Journal of Zoo Animal Medicine 19:1-7 Abstract: Sixteen African elephants (Loxodonta africana) were immobilized with single i.m. injections of carfentanil citrate (2.1 ± 0.3 µg/kg body weight). All elephants were laterally recumbent in 10.1 ± 3.7 min. An additional elephant which received 1.4 µg /kg carfentanil did not become recumbent and additional carfentanil was required for immobilization. Following immobilization, nine elephants were maintained in lateral recumbency by administration of multiple i.v. injections of carfentanil, one elephant received a single i.v. dose of ketamine hydrochloride, and four were intubuted and administered 1-1.5% halothane in oxygen. Because a short duration of immobilization was desired, three elephants were not given additional drugs. The duration of immobilization ranged from 4 to 187 min. Following a variety of medical and surgical procedures, 13 elephants received nalmefene hydrochloride, two elephants received diprenorphine, and two elephants received both diprenorphine and nalmefene; antagonists were administered either i.v. and i.m. or i.v. and s.c. Sixteen of 17 elephants were standing in 2.9 ± 1.4 min; the standing time of one elephant was not recorded. See also nalmefene monograph.
k) Jacobson,E.R., Heard,D.J., Caligiuri,R., and Kollias,G.V. 1987. Physiologic effects of etorphine and carfentanil in African elephants. Proc.1st.Intl.Conf.Zool.Avian Med. Pages: 525-527 Abstract: (Full text): The effects of etorphine hydrochloride and carfentanil citrate on blood pressure, heart rate, respiration and body temperature were determined in a group of captive African elephants (Loxodonta africana). Fourteen African elephants, weighing 450 kg to 4000 kg, divided into 2 groups of 6 and 8 elephants each, received either etorphine hydrochloride (2.9 ± 0.7 µg/kg of body weight; mean ± SD) or carfentanil citrate (2.0 ± 0.2 µg/kg of body weight) respectively. The mean time for lateral recumbency in elephants which received etorphine was 31 ± 9.1 minutes while the mean time for lateral recumbency in elephants which received carfentanil was 10.3 ± 4.1 minutes. Following immobilization, a 18 gauge catheter was inserted into an auricular artery, the catheter connected to a pressure transducer system and systolic, diastolic, and mean arterial pressures were monitored by use of a multichannel oscilloscope. Systolic, diastolic, mean arterial pressures, heart rate, respiration, and temperature were recorded every 5 minutes over a 45 to 60 minute period. Elephants were maintained in lateral recumbency over the period of monitoring by intravenous injections of either etorphine or carfentanil.
Following immobilization with etorphine, mean physiological values for elephants were: systolic pressure, 229 ± 33 mm Hg; diastolic pressure, 141 ± 30 mm Hg; mean arterial pressure, 177 ± 30 mm Hg; heart rate 64 ± 10 beats/minute; respiratory rate 10 ± 4 breaths/minute; body temperature, 97 ± 2°F. Mean physiological values at the final time period of monitoring prior to antagonism were: systolic pressure, 217 ± 40 mm Hg; diastolic pressure, 147 ± 36 mm Hg; mean arterial pressure, 176 ± 38mm Hg; heart rate 77 ± 13 beats/minute; respiratory rate 12 ± 1 breaths/minute; body temperature, 98 ± 2°F. Immediately following the last recording, all 8 elephants received the experimental opioid antagonist, nalmefene hydrochloride, administered at 38 ± 11 µg/kg of body weight given both subcutaneously and intravenously. The mean standing time following administration of nalmefene was 1.4 ± 0.7 minutes.
Immediately following immobilization with carfentanil, mean physiological values for elephants were: systolic pressure, 232 ± 28 mm Hg; diastolic pressure, 148 ± 14 mm Hg; mean arterial pressure, 183 ± 24 mm Hg; heart rate 57 ± 11 beats/minute; respiratory rate 11 ± 3 breaths/minute; body temperature, 99 ± 1°F. Mean physiological values at the final time period of monitoring prior to antagonism were: systolic pressure, 224 ± 29 mm Hg; diastolic pressure, 146 ± 13 mm Hg; mean arterial pressure, 179 ± 18mm Hg; heart rate 65 ± 11 beats/minute; respiratory rate 12 ± 1 breaths/minute; body temperature, 99 ± 1°F. Immediately following the last recording, all 6 elephants received the opioid antagonist, nalmefene hydrochloride administered at 62 ± 17 µg/kg of body weight given both subcutaneously and intravenously. The mean standing time following administration of nalmefene was 2.6 ± 1.6 minutes.
The results of this study indicated that both etorphine and carfentanil resulted in high blood pressure over the duration of the period of monitoring. Based upon these findings, both etorphine hydrochloride and carfentanil citrate are not recommended as the primary agent in performing major invasive surgical procedures in African elephants.
Raath,J.P. 1993. Chemical capture of the African elephant. In: The Capture and care manual : capture, care, accommodation and transportation of wild African animals. Pretoria : Wildlife Decision Support Services : South African Veterinary Foundation, Pretoria pp. 484-511