Analgesia, Sedação e Anestesia em Repteis 2015

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ExoticsCon 2015 Pre-conference Proceedings 163
Reptile Sedation, Anesthesia and Analgesia
Christoph Mans, Dr med vet, Dipl ACZM
Session #284
Affiliation: From the School of Veterinary Medicine, University of Wisconsin-Madison, 2015 Linden 
Drive, Madison, WI 53706, USA.
Abstract: Utilizing chemical restraint methods in reptile patients is commonly needed for diagnostic and 
therapeutic procedures. However, the significant differences in anatomy and physiology amongst different 
groups of reptiles as well as several other factors such as body temperature, injection site and route as well 
as underlying disease processes make sedation and anesthesia in reptiles challenging at times. Reducing 
environmental temperatures below the preferred temperature range of reptile patients will lead to a delay 
in onset of action of anesthetic drugs, longer action and delayed recovery. If temperatures are increased, 
onset of sedation or anesthesia is more rapid, but the duration of effect can be shorter. Therefore it is 
critical to ensure that reptile patients are maintained at an appropriate temperature prior to and during 
sedation and anesthesia. 
Sedation, Anesthesia and Analgesia
Injection of sedative and anesthetic drugs in the caudal body-half should be avoided if possible, since some drugs 
may undergo a hepatic first pass effect, which may be more important for most anesthetic drugs, compared to 
the more often discussed renal first-pass effect.1,3 Plasma levels and efficacy of anesthetic drugs can be greatly 
reduced and may require repeated drug administration.3
Historically the intramuscular route has been recommended as the route of choice for non-vascular administra-
tion of anesthetic and sedative drugs in reptiles (Tables 1 and 2). However, the subcutaneous route provides 
a suitable alternative, in particular in animals with reduced muscle mass or if larger volumes of drugs need to 
be administered. While the onset of effect is often slower following subcutaneous administration, the depth of 
sedation or anesthesia reached is ultimately similar following intramuscular administration.1
By considering short acting drugs and partial or completely reversible drug protocols for sedation and anesthesia, 
prolonged recoveries or fatalities can be avoided. Sedation often is sufficient for most diagnostic procedures as 
well as certain therapeutic procedures, particularly if combined with local anesthetics (Table 1).2 Lidocaine and 
bupivacaine can be used for local infiltration, nerve block as well as for spinal anesthesia in reptiles.2,4
Our knowledge on reptile analgesia continues to grow, and increasing scientific evidence is available to guide 
the selection of drugs which are likely to provide analgesia in reptiles.1,5 However, the side effects of opioid 
analgesics, such as sedation and respiratory depression and well as differences in response amongst groups of 
reptiles should be carefully considered. In general most mu-opioid receptor agonists have been shown to provide 
analgesia in turtles and tortoises as well as lizards and crocodilians. Drugs such as morphine, hydromorphone, 
fentanyl and tramadol are most commonly used (Table 3).5-7 
However, limited information is available in regards to drug side effects across different reptile species. 
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Table 1. Sedation protocols commonly used in reptiles.a 
 
 
 
Protocol Dose [mg/kg] Route
b Species Comments 
Chelonians 
Midazolam 2 SC/IM Red-eared slider Mild sedation, inconsistent effects, completely reversible 
Dexmedetomidine 
+ midazolam 0.1 + 1 SC/IM 
Red-eared slider 
NA box turtles 
Mild to moderate sedation, 
completely reversible; rapid 
recovery after reversal 
Dexmedetomidine 
+ midazolam + 
ketamine 
0.1 
+ 1 + 2 SC/IM Red-eared slider 
Moderate sedation, partially 
reversible; rapid recovery after 
reversal 
Medetomidine + 
ketamine 0.1 + 5 SC/IM Red-eared slider 
Deep sedation, suitable for 
intubation 
Medetomidine + 
ketamine + morphine 
0.15 + 
2.5 + 1 SC/IM Tortoises 
Deep sedation - light anesthesia, 
partially reversible; rapid recovery 
after reversal 
Medetomidine + 
midazolam + morphine 
0.2 + 2 + 
1 SC/IM Tortoises 
Deep sedation - light anesthesia, 
completely reversible; rapid 
recovery after reversal. 
Alfaxalone 10 IM Red-eared slider Moderate sedation, suitable for intubation 
Propofol 2-5 IV Moderate sedation - light anesthesia 
Lizards 
Dexmedetomidine 
+ midazolam 
0.1 
+ 1 SC/IM 
Bearded dragon, 
green iguana 
Moderate sedation, completely 
reversible; rapid recovery after 
reversal 
Dexmedetomidine 
+ midazolam + 
ketamine 
0.05 - 
0.1 
+ 1 + 3 
SC-IM Bearded dragon, green iguana 
Moderate - deep sedation, partially 
reversible; rapid recovery after 
reversal 
Alfaxalone 10 IM, IV Green iguana 
Light-moderate sedation, maximum 
effect after ~ 5 min, duration of 
effect ~ 10 min 
Propofol 3-5 IV, IO Deep sedation - light anesthesia 
Snakes 
Midazolam 1-2 IM Mild sedation, inconsistent effects 
Telazol 2-5 SC, IM Large snakes Mild-moderate sedation, endotracheal intubation 
Ketamine 5-10 SC, IM Mild-moderate sedation, endotracheal intubation 
Propofol 3-5 IV Moderate sedation - light anesthesia 
aAtipamezole is used to antagonize medetomidine/dexmedetomidine in 1:1 volume, SC or IM. Flumazenil is used 
to antagonize midazolam: 0.05mg/kg SC, IM or IV. Nalaxone is used to antagonize morphine or hydromorphone: 
0.04mg/kg SC, IM, or IV. 
bAbbreviations: SC=subcutaneous; IM=intramuscular; IV=intravenous; IO=intraosseous. 
 
Table 1. Sedation protocols commonly used in reptiles.a
ExoticsCon 2015 Pre-conference Proceedings 165
 
 
Table 2. Anesthetic protocols commonly used in reptiles.a 
 
 
 
 
 
Protocol Dose [mg/kg] Route
b Species Comments 
Chelonians 
Medetomidine + midazolam + 
ketamine + hydromorphone 
0.15 
+ 0.5 + 10 
+ 0.5 
SC/IM Tortoises Surgical anesthesia, maintain with gaseous anesthetic if necessary 
Medetomidine + ketamine 0.2 + 10 SC/IM Red-eared slider Surgical anesthesia partially reversible 
Medetomidine + ketamine + 
morphine 
0.1 + 10 
+1.5 SC/M Map turtle 
Surgical anesthesia, Administration 
of nalaxone recommended if 
recovery is slow or to prevent 
renarcotization 
Dexmedetomidine + ketamine + 
hydromorphone 
0.15 
+ 10 
+ 0.5 
SC/IM 
Surgical anesthesia, supplement 
with gaseous anesthesia if 
necessary 
Propofol 2-10 IV Induction agent; use lower dose in large tortoises 
Propofol 10-20 IV Red-eared slider Light anesthesia for ~ 60 min (10mg/kg) or ~ 90 min (20mg/kg) 
Alfaxalone 20 IM Red-eared slider Induction agent; light anesthesia for 28 ± 13 min at 20°C 
Lizards 
Alfaxalone 20-30 IM Green iguana 
Induction agent, effect after 5 
minutes, duration of effect 20-40 
min 
Alfaxalone 10 IV Green iguana Induction agent; maintain with gaseous anesthetic 
Propofol 5-10 IV, IO Green iguana Induction agent, apnea common, requires intubation and IPPV 
Snakes 
Propofol 3-10 IV, IC Induction agent; maintain with gaseous anesthetic 
Alfaxalone 9 IV Australian snakes 
Light anesthesia, endotracheal 
intubation 
Telazol® 2-6 IM Induction agent; maintain with gaseous anesthetic 
All reptiles 
Isoflurane 2-5% Induction 5%, maintenance 2-3% 
Sevoflurane 2.5-8% Induction 7-8%, maintenance 2.5-4.5% 
aAtipamezole is used to antagonize medetomidine/dexmedetomidine in 1:1 volume, SC or IM. Flumazenil is used to 
antagonize midazolam: 0.05 mg/kg SC, IM or IV. Nalaxone is used to antagonize morphine or hydromorphone: 0.04 
mg/kg SC, IM, or IV. 
bAbbreviations: SC=subcutaneous; IM=intramuscular; IV=intravenous; IO=intraosseous. 
 
Table 2. Anesthetic protocols commonly used in reptiles.a
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Drugs previously believed to have analgesic properties in reptiles, such as butorphanol and buprenorphine, have 
so far not shown to be effective in providing analgesia in reptiles.7,8 Non-steroidalanti-inflammatory drugs are 
frequently administered to reptiles. However, to date, no evidence for analgesic efficacy of these drugs in reptiles 
exists. Meloxicam appears to be safe and even at high doses no adverse effects were found.9 Future research 
is necessary in order to determine safe and effective analgesic drug protocols for the reptile species most com-
monly kept in captivity.
References
1. Sladky KK, Mans C. Clinical anesthesia in reptiles. J Exot Pet Med. 2012;21:17-31.
2. Schumacher J, Mans C. Anesthesia. In: Mader D, Divers, SJ, eds. Current Therapy in Reptile Medicine and 
Surgery. St. Louis, MO:WB Saunders;2013.
3. Kummrow MS, Tseng F, Hesse L, et al. Pharmacokinetics of buprenorphine after single-dose subcutaneous 
administration in red-eared sliders (Trachemys scripta elegans). J Zoo Wildl Med. 2008;39:590-595.
4. Mans C. Clinical technique: Intrathecal drug administration in turtles and tortoises. J Exot Pet Med. 
2014;23:67-70.
5. Sladky KK. Analgesia In: Mader D, Divers SJ, eds. Current Therapy in Reptile Medicine and Surgery. St. 
Louis. MO: WB Saunders;2013.
6. Giorgi M, Salvadori M, De Vito V, et al. Pharmacokinetic/pharmacodynamic assessments of 10 mg/kg tra-
madol intramuscular injection in yellow-bellied slider turtles (Trachemys scripta scripta). J Vet Pharmacol 
Ther. 2015. In press.
7. Mans C, Lahner LL, Baker BB, et al. Antinociceptive efficacy of buprenorphine and hydromorphone in 
red-eared slider turtles (Trachemys scripta elegans). J Zoo Wildl Med. 2012;43:662-665.
8. Sladky KK, Miletic V, Paul-Murphy J, et al. Analgesic efficacy and respiratory effects of butorphanol and 
morphine in turtles. J Am Vet Med Assoc. 2007;230:1356-1362.
9. Divers SJ, Papich M, McBride M, et al. Pharmacokinetics of meloxicam following intravenous and oral 
administration in green iguanas (Iguana iguana). Am J Vet Res. 2010;71:1277-1283.
 
 
Table 3. Analgesic drugs commonly used in reptiles. 
 
 
Drug Dose [mg/kg] Route Species Comments 
Hydromorphone 0.5-1 SC/IM Chelonians q24h 
Morphine 1-2 SC/IM Chelonians q24h 
Tramadol 5-10 PO, SC/IM Chelonians q48-72h 
Buprenorphine 0.02 – 0.2 SC/IM Chelonians No analgesia demonstrated 
Butorphanol 1-8 SC/IM Chelonians No analgesia demonstrated 
Meloxicam 0.2 PO, SC/IM Green iguanas q24h, PK data only 
Ketoprofen 2 SC/IM Green iguanas > q24h, PK data only 
Table 3. Analgesic drugs commonly used in reptiles.