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Methadone

Grade

Opiate Analgesia

Therapeutics

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About Methadone and Analgesia

Methadone is a synthetic μ receptor opioid agonist with affinity for NMethyl-D-Aspartate receptors, which confers its potent analgesic properties comparable to morphine (Ref).

Rabbits

  • Methadone is a popular emerging opiate used extensively for multimodal sedation or anaesthesia and opiate analgesia (ref)

Major Species

  • Methadone is extensively metabolised in the liver and exhibits fewer adverse effects than morphine in most veterinary species because metabolites do not mediate methadone's receptor effect (Schumacher et al., 2017; Animal Refs).

Treatment Goals

  • Analgesia

  • Multimodal Sedation or Anaesthesia

Treatment End Point


Adverse Effects

  • In most veterinary species, these may include bradycardia, hypertension, alterations in gut motility, and sedation.

Contraindications


Reproductive Safety

  • Pregnancy:

  • Lactation:

  • Male Fertility:

  • Female Fertility:

  • Neonates:

Significant Interactions


Alternative Products


Alternative Protocols


Formulations

  • UK Availability: Methadone is a Schedule 2 drug; its usage must be logged, and it should be kept in a locked drug safe (SPC Data).

Evidence

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1 Species-Specific Evidence Review

  1. Benato, L., Rooney, N.J., Murrell, J.C., 2019. Pain and analgesia in pet rabbits within the veterinary environment: a review. Veterinary Anaesthesia and Analgesia 46, 151–162. https://doi.org/10.1016/j.vaa.2018.10.007

  2. Gardhouse, S., Sanchez, A., 2022. Rabbit Sedation and Anesthesia. Veterinary Clinics of North America: Exotic Animal Practice 25, 181–210. https://doi.org/10.1016/j.cvex.2021.08.012

  3. Mercado, L., Desprez, I., Lafuma, F., Sarran, D., Brune, J., Huynh, M., Abadie, J., Risi, E., 2023. Successful management of acinar adenocarcinoma by pulmonary lobectomy in a pet rabbit (Oryctolagus cuniculus). Journal of Exotic Pet Medicine 47, 9–13. https://doi.org/10.1053/j.jepm.2023.06.002

  4. Miller, A.L., Leach, M.C., 2023. Pain Recognition in Rabbits. Veterinary Clinics of North America: Exotic Animal Practice 26, 187–199. https://doi.org/10.1016/j.cvex.2022.07.007

  5. Ozawa, S., Cenani, A., Sanchez-Migallon Guzman Lv, D., 2023. Treatment of Pain in Rabbits. Veterinary Clinics of North America: Exotic Animal Practice 26, 201–227. https://doi.org/10.1016/j.cvex.2022.09.001

  6. Tan, T., Langlois, I., Giron, C., Finck, C., Rembeaux, H., Vigneau, A.-L., Dallaire, A.D., 2023. Unilateral para-ureteral cyst with ipsilateral hydroureteronephrosis in a domestic rabbit (Oryctolagus cuniculus). Journal of Exotic Pet Medicine 47, 4–8. https://doi.org/10.1053/j.jepm.2023.06.001

  7. Vieu, S., Dekerle, B., Monge, E., Raymond, P., Vial, J., Maurice, E., 2022. Surgical treatment of a shoulder joint luxation combined to a Salter-Harris type I fracture of the proximal humerus in a pet rabbit (Oryctolagus cuniculus). Journal of Exotic Pet Medicine 43, 18–21. https://doi.org/10.1053/j.jepm.2022.07.003

2 Condition-Specific Evidence Review

  1. Benato, L., Rooney, N.J., Murrell, J.C., 2019. Pain and analgesia in pet rabbits within the veterinary environment: a review. Veterinary Anaesthesia and Analgesia 46, 151–162. https://doi.org/10.1016/j.vaa.2018.10.007

  2. Gardhouse, S., Sanchez, A., 2022. Rabbit Sedation and Anesthesia. Veterinary Clinics of North America: Exotic Animal Practice 25, 181–210. https://doi.org/10.1016/j.cvex.2021.08.012

  3. Mercado, L., Desprez, I., Lafuma, F., Sarran, D., Brune, J., Huynh, M., Abadie, J., Risi, E., 2023. Successful management of acinar adenocarcinoma by pulmonary lobectomy in a pet rabbit (Oryctolagus cuniculus). Journal of Exotic Pet Medicine 47, 9–13. https://doi.org/10.1053/j.jepm.2023.06.002

  4. Miller, A.L., Leach, M.C., 2023. Pain Recognition in Rabbits. Veterinary Clinics of North America: Exotic Animal Practice 26, 187–199. https://doi.org/10.1016/j.cvex.2022.07.007

  5. Ozawa, S., Cenani, A., Sanchez-Migallon Guzman Lv, D., 2023. Treatment of Pain in Rabbits. Veterinary Clinics of North America: Exotic Animal Practice 26, 201–227. https://doi.org/10.1016/j.cvex.2022.09.001

  6. Tan, T., Langlois, I., Giron, C., Finck, C., Rembeaux, H., Vigneau, A.-L., Dallaire, A.D., 2023. Unilateral para-ureteral cyst with ipsilateral hydroureteronephrosis in a domestic rabbit (Oryctolagus cuniculus). Journal of Exotic Pet Medicine 47, 4–8. https://doi.org/10.1053/j.jepm.2023.06.001

  7. Vieu, S., Dekerle, B., Monge, E., Raymond, P., Vial, J., Maurice, E., 2022. Surgical treatment of a shoulder joint luxation combined to a Salter-Harris type I fracture of the proximal humerus in a pet rabbit (Oryctolagus cuniculus). Journal of Exotic Pet Medicine 43, 18–21. https://doi.org/10.1053/j.jepm.2022.07.003

3 Substance-Specific Evidence Review

  1. Pujol, J., Vergneau-Grosset, C., Beaudry, F., Gaudette, F., Vigneault, A., Benedetti, I.-C.C., 2023. Pharmacokinetics and innocuity of a single dose of intravenous, intramuscular, and subcutaneous methadone in the domestic rabbit (Oryctolagus cuniculus). Journal of Exotic Pet Medicine 47, 41–46. https://doi.org/10.1053/j.jepm.2023.08.001

Supplementary Material 

2 Additional Material Consulted

  1. Booth, D., 2011. Small Animal Clinical Pharmacology and Therapeutics - 2nd Edition [WWW Document]. URL https://shop.elsevier.com/books/small-animal-clinical-pharmacology-and-therapeutics/boothe/978-0-7216-0555-5 (accessed 1.24.24).

  2. Maddison, G., 2008. Small Animal Clinical Pharmacology E-Book: 2nd edition | Edited by Jill E. Maddison | ISBN: 9780702037252 [WWW Document]. Elsevier Asia Bookstore. URL https://www.asia.elsevierhealth.com/small-animal-clinical-pharmacology-e-book-9780702037252.html (accessed 1.23.24).

  3. Plumb, n.d. Methadone @ https://app.plumbs.com/ [WWW Document]. URL https://app.plumbs.com/drug/Ez66Xm6taBPROD?source=search&searchQuery=methadone (accessed 1.27.24).

  4. Quesenberry, K.E. (Ed.), 2021. Ferrets, rabbits, and rodents: clinical medicine and surgery, Fourth edition. ed. Elsevier, St. Louis, Missouri.

  5. Schumacher, M.A., Basbaum, A.I., Naidu, R.K., 2017. Opioid Agonists & Antagonists, in: Katzung, B.G. (Ed.), Basic & Clinical Pharmacology. McGraw-Hill Education, New York, NY.

  6. Varga-Smith, M., 2022. Textbook of Rabbit Medicine - 9780702084034 | Elsevier Health [WWW Document]. Elsevier UK. URL https://www.uk.elsevierhealth.com/textbook-of-rabbit-medicine-9780702084034.html (accessed 1.23.24).

3 Conference Proceedings

  1. Di Girolamo, N., 2020. Practical Approach to Rabbit Anesthesia  ExoticsCon Virtual 2020 Proceedings, in: VIN.Com.

  2. Pathak, D., 2020. Effects of injectable analgesics on selected gastrointestinal physiological parameters in rabbits [WWW Document]. URL http://thevetgazette.com/main/2020/4/29/effects-of-injectable-analgesics-on-selected-gastrointestina.html (accessed 1.26.24).

  3. Touzot-Jourde, G., 2015. Comparison of methadone and morphine sedation and analgesia in the NZW rabbit. Vet Pharm & Therapeutics 38, 1–81. https://doi.org/10.1111/jvp.12246

Monograph Details

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