Buprenorphine Hydrochloride




  • Injectable: 0.324 mg (equivalent to 0.3 mg base/mL) in 1 mL ampules.


Buprenorphine, a thebaine derivative, is a synthetic partial opiate agonist. It has some activity at the mu receptor which gives it a longer duration of analgesic action than butorphanol.

Buprenorphine is considered to be approximately 30 times stronger than morphine. However, morphine is a much stronger pain reliever due to the fact that morphine has more activity at the mu receptor. The duration of action may last from 8 to 12 hours. However, in rats, the duration of action is reported to be 6 hours, but may be prolonged in the presence of impaired liver function. 42

Respiratory depression, decreased heart rate, and blood pressure are possible with this drug.

It is well absorbed IM, and SQ, and is metabolized in the liver. In rats, the drug concentrates in the liver, brain, gastrointestinal tract, and placenta. It is then excreted in urine, and via breast milk. While studies have not shown teratogenicity, there is not sufficient documentation at this time for safety in pregnant or lactating animals. It is, therefore, recommended to avoid giving in pregnant or lactating rats.


Used as an analgesic for pain relief with surgical procedures.

Drug Interactions or Contraindications

  • It is incompatible with diazepam and lorazepam.
  • Compatible drugs are acepromazine, atropine, diphenhydramine, droperidol, glycopyrolate, hydroxyzine, scopolamine, and xylazine.
  • If used with other central nervous system depressants such as anesthetic agents, antihistamines, phenothiazines, barbiturates and tranquilizers, may increase central nervous system and respiratory depression.
  • It is not recommended to give with MAO inhibitors.
  • Use with caution in respiratory compromise and impaired liver or renal function.

Adverse Reactions

CNS: sedation, confusion, lethargy, agitation.

CV:  bradycardia

Resp:  decreased respiratory rate

GI:  pica, constipation

GU:  urinary retention

Skin:  itching


In the event there are signs of overdose such as cardiac and respiratory depression administer the following:

  • naloxone 0.01 to 0.1 mg/kg SC, IP (narcotic reversal) 1, 34, 41, 42
  • fluids
  • O2
  • vasopressors

Dosage Recommendations

0.1 mg/kg to 0.25 mg/kg, PO, q8hr to q12hr  41


0.02 mg/kg to 0.50 mg/kg , SQ , IP , IV, q6hr to q12hr  1, 28


0.01 mg/kg to 0.05 mg/kg, SQ, IV, q8hr to q12hr  41


0.05 mg/kg to 0.1 mg/kg , SQ , q6hr to q12hr  2, 34, 42


  • Important note to veterinarians: It has been reported that rats may develop pica after receiving this drug.1,2,4

    Be sure to instruct pet owners to monitor for this behavior if an opioid medication is given, and to contact vet immediately. Also have the pet owner remove the rat from any bedding source that might be chewed and ingested until medication has passed through the system. In severe cases it may be necessary to reduce or eliminate the drug from the rat’s system by providing warmed SQ or IV fluids. 21

    It is also important to be aware that pica may be observed, in rats, where pain has not been adequately addressed.

    *Note: per veterinary discretion, when discharging a rat to home postop, or for palliative care, injectable buprenorphine may be given, by needless syringe, to the buccal (to cheek tissue inside mouth) area.
    Anecdotally: pet owners have noted less issue with pica at home when administered to the buccal area.

  • Store drug at room temperature.
  1. Anesthesia and Analgesia in Laboratory Animals at UCSF. (2005, April 5). Retrieved December 20, 2008, from http://www.iacuc.ucsf.edu/Proc/awRatFrm.asp. Also, (2018, November ). Retrieved September 5, 2020, from https://larc.ucsf.edu/veterinary-information.
  2. Clark, J., Myers, P., Goelz, M., Thigpen, J., & Forsythe, D. (1997). Pica behavior associated with buprenorphine administration in the rat. Lab Anim Sci, 47(3), 300-3.
  3. Leach, M., Forrester, A., & Flecknell, P. (2010). Influence of preferred foodstuffs on the antinociceptive effects of orally administered buprenorphine in laboratory rats. Lab Anim., 44(1), 54-8.
  4. Lee-Parritz, D. (2007). Analgesia for Rodent Experimental Surgery. Israel Journal of Veterinary Medicine, 62(3-4), 74-78. Retrieved December 20, 2008, from https://www.isrvma.org/article/62_3-4_2.htm.
  5. Rat Analgesics. (n.d.). Retrieved December 20, 2008, from https://campusvet.wsu.edu/infofac/ratanalgesicsuse.htm. See: https://web.archive.org/web/20040823193416/https://campusvet.wsu.edu/infofac/ratanalgesicsuse.htm
  6. Vogler, G. (2005). Anesthesia and Analgesia. In Suckow, M., Weisbroth, S., & Franklin, C. (Eds). The Laboratory Rat, Second Edition (American College of Laboratory Animal Medicine) (pp. 627-678). Toronto: Academic Press.
  7. Takeda, N., Hasegawa, S., Morita, M., & Matsunaga, T. (1993). Pica in rats is analogous to emesis: an animal model in emesis research. Pharmacology, biochemistry, and behavior, 45(4), 817–821. https://doi.org/10.1016/0091-3057(93)90126-e


Links to

Linked from


The Rat Guide and its affiliates accept no responsibility for misuse or misunderstanding of its information. This guide in whole or part, exists solely for the purpose of recognizing and understanding the care and illnesses in the pet rat. Please seek advice and treatment from a qualified Veterinarian if your rat is ill.

2000 - 2024 by Karen Grant RN. All rights reserved.
All other written and visual materials used by permission of specific authors for the sole use of the Rat Guide. Please visit our Privacy Policy for details.
Brought to you by KuddlyKorner4u
See Logos page for linking to the Rat Guide.
Contact us here: Rat Guide Team
Please note: Rat Guide email is not checked daily. Send e-mail to if you have an urgent medical problem with your pet rat. When possible, it is always best to take your rat to a qualified rat veterinarian.