What routes can Morphine be administered by?

Available routes: IV, IM, SC, EPIDURAL.

Is Morphine a controlled substance?

Yes — Morphine is a controlled substance under US federal law.

What is the constant rate infusion (CRI) dose for Morphine?

Morphine has 1 CRI dose rule in the ExoticRx formulary, covering Dog (Domestic). See the CRI section on this page for routes, dose ranges, and source citations.

Morphine

Calculate dosage

Sourced from published veterinary references. Awaiting credentialed clinical reviewer — our editorial process.

Morphine is dosed at 0.5–2 mg/kg SC, IM q2-4h in rabbits, per Carpenter JW, Hawkins MG. Personal communication; 2020. | Morissey JM, Carpenter JW. Appendix: Formulary. In: Quesenberry KE, OrcuttCJ, Mans C, et al. Ferrets, Rabbits and Rodents: Clinical Medicine and Surgery, 4th ed., Elsevier, St. Louis, MO; 2021:620-630. — Source: Carpenter's Exotic Animal Formulary, 6th Ed, p.863. Verify against current literature before clinical use.

Drug Class

Analgesic

Routes

IVIMSCEPIDURAL

Indications

Analgesia Analgesia (antinociception) - electro-stimulation model Analgesia (caudal body / thermal analgesia)Analgesia (full mu opioid)Analgesia (opioid)CRIImmobilization (sedation/anesthesia)Moderate to severe painOpioid analgesia Perioperative analgesia (coeliotomy/gonadectomy)PROVIDED analgesia Regional analgesia of the caudal body

Show all 16

Sedation/analgesiaSevere painSurgical analgesia Surgical analgesia (hindlimb, perineal)

Mechanism of Action

Prototype full mu-opioid receptor agonist. Activates mu, kappa, and delta opioid receptors producing analgesia, sedation, and euphoria.

Side effects & warnings

Histamine release with rapid IV injection (hypotension, bronchoconstriction — give slowly). Vomiting and defecation common initial effects. Respiratory depression. Cats: may cause excitation/dysphoria at higher doses. Controlled substance (Schedule II).

Species with Morphine dosing data (34 dose rules)

African Clawed Frog Argentine Tegu Axolotl Bearded Dragon Betta (Siamese fighting fish)Cat (Domestic)Chicken (Poultry)Chinchilla Degu Dog (Domestic)Dwarf Hamster Eastern Box Turtle Ferret Fire Salamander Goldfish Green Iguana

Controlled Substance

Controlled substance in the US

Controlled-drug status and schedules differ by country — check your local scheduling rules.

Evidence levels across 34 dose rules

Moderate×19Weak×8Anecdotal×1Strong×6

Each ExoticRx dose rule is graded by the strength of its primary evidence — see the editorial process.

Constant rate infusion (CRI)

Morphine CRI dose rule from the ExoticRx formulary. Verify against current literature before clinical use; CRI rates differ from bolus dosing and route, dilution, and monitoring matter. Sign in for the complete per-species CRI protocol set.

Species	Route	Rate	Indication	Evidence	Source
Dog (Domestic)	IV	0.1–0.5 mg/kgq2-4h bolus or 0.1-0.3 mg/kg/h CRI	Severe pain, CRI	Strong	Lucas AN, Firth AM, Anderson GA, Vine JH, Edwards GA. Comparison of the effects of morphine administered by constant-rate intravenous infusion or intermittent intramuscular injection in dogs. J Am Vet Med Assoc. 2001;218(6):884-891. doi:10.2460/javma.2001.218.884 — Plumb's 10th ed printed p.907, Morphine monograph spanning p.907-911.

Dog (Domestic)IV
0.1–0.5 mg/kgq2-4h bolus or 0.1-0.3 mg/kg/h CRI
Severe pain, CRI
Strong

Sample dosing (2 of 34 cited rules)

A dog/cat sample is shown here. Cited dosing for all 28 species — reptiles, birds, pocket pets, livestock, and equine — is free on the per-species pages above. Pro adds the weight-based calculator for every species.

Species	Route	Dose	Frequency	Evidence	Source
Dog (Domestic)	IV	0.1–0.5 mg/kg	q2-4h bolus or 0.1-0.3 mg/kg/h CRI	Strong	Lucas AN, Firth AM, Anderson GA, Vine JH, Edwards GA. Comparison of the effects of morphine administered by constant-rate intravenous infusion or intermittent intramuscular injection in dogs. J Am Vet Med Assoc. 2001;218(6):884-891. doi:10.2460/javma.2001.218.884 — Plumb's 10th ed printed p.907, Morphine monograph spanning p.907-911.
Dog (Domestic)	EPIDURAL	0.1 mg/kg	Single injection	Strong	Plumb's Veterinary Drug Handbook, 10th ed (2023), Morphine monograph, printed p.910, DOGS - Analgesia (extra-label), item c) Epidural. -Compilation only — we have not located an independent source that prints this figure.

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Backed by 27 published sourcesShow

· 188. Ritchie BW, Harrison GJ. Formulary. In: Ritchie BW, Harrison GJ, Harrison LR, eds. Avian Medicine: Principles and Applications; Wingers Publishing, Lake Worth, FL; 1994:457-478. — Source: Carpenter's Exotic Animal Formulary, 6th Ed, p.644 — Carpenter's Exotic Animal Formulary 6th ed, Table 6.4 (Chemical Restraint/Anesthetic/Analgesic Agents Used in Backyard Poultry,).
· 294. Mans C. Clinical technique: intrathecal drug administration in turtles and tortoises. J Exot Pet Med. 2014;23:67-70. — Source: Carpenter's Exotic Animal Formulary, 6th Ed, p.255 doi:10.1053/j.jepm.2013.11.011 — Carpenter's Exotic Animal Formulary 6th ed, Table 4.6 (Analgesic (Including Antiinflammatory) Agents Used in Reptiles).

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Calculate Dosage for Morphine

Lucas AN, Firth AM, Anderson GA, Vine JH, Edwards GA. Comparison of the effects of morphine administered by constant-rate intravenous infusion or intermittent intramuscular injection in dogs. J Am Vet Med Assoc. 2001;218(6):884-891. doi:10.2460/javma.2001.218.884 — Plumb's 10th ed printed p.907, Morphine monograph spanning p.907-911.

434. Sladky KK, Kinney ME, Johnson SM. Analgesic efficacy of butorphanol and morphine in bearded dragons and corn snakes. J Am Vet Med Assoc. 2008;233:267-273. / 488. Williams CJ, James LE, Bertelsen MF, et al. Tachycardia in response to remote capsaicin injections as a model for nociception in the ball python (Python regius). Vet Anaesth Analg. 2015;43:429-434. — Source: Carpenter's Exotic Animal Formulary, 6th Ed, p.255 doi:10.2460/javma.233.2.267 — Carpenter's Exotic Animal Formulary 6th ed, Table 4.6 (Analgesic (Including Antiinflammatory) Agents Used in Reptiles). — SOURCE ROW: Mader's Reptile Medicine and Surgery — "Morphine 1.0-5.0 SC, IM q24h — Good analgesic efficacy in RES & bearded dragons; unknown efficacy in snakes", with respiratory depression noted as not studied. A higher figure of 10 mg/kg IM is reported for bearded dragons in another formulary; that row was not verifiable in the held corpus and this rule is not raised on it.

· 51. Flecknell PA. Analgesia and post-operative care. Laboratory Animal Anaesthesia; 2016:141-192. | 122. Meredith A. BSAVA Small Animal Formulary: Part B: Exotic Pets, British Small Animal Veterinary Association, Quedgeley, Gloucester, UK; 2015. — Source: Carpenter's Exotic Animal Formulary, 6th Ed, p.792 doi:10.1016/b978-0-12-800036-6.00004-1 — Carpenter's Exotic Animal Formulary 6th ed, Table 9.4 (Analgesic Agents Used in Rodents).

· 7. Allweiler SI. How to improve anesthesia and analgesia in small mammals. Vet Clin North Am Exot Anim Pract. 2016;19:361-377. | 130. Morrisey JK, Carpenter JW. Formulary. In: Quesenberry KE, Carpenter JW, eds. Ferrets, Rabbits, and Rodents: Clinical Medicine and Surgery, 4th ed., Elsevier, St. Louis, MO; 2021:620-630. — Source: Carpenter's Exotic Animal Formulary, 6th Ed, p.792 doi:10.1016/j.cvex.2016.01.012

· 7. Allweiler SI. How to improve anesthesia and analgesia in small mammals. Vet Clin North Am Exot Anim Pract. 2016;19:361-377.; 130. Morrisey JK, Carpenter JW. Formulary. In: Quesenberry KE, Carpenter JW, eds. Ferrets, Rabbits, and Rodents: Clinical Medicine and Surgery, 4th ed., Elsevier, St. Louis, MO; 2021:620-630. — Source: Carpenter's Exotic Animal Formulary, 6th Ed, p.792 doi:10.1016/j.cvex.2016.01.012

· A critical review on the pharmacodynamics and pharmacokinetics of non-steroidal anti-inflammatory drugs and opioid drugs used in reptiles. Vet Anim Sci. 2022;17:100267. PMID: 36043206; PMCID: PMC9420515; DOI: 10.1016/j.vas.2022.100267. (Table 7; original data cited as Greenacre et al., 2006) URL: https://pmc.ncbi.nlm.nih.gov/articles/PMC9420515/

· Allweiler SI. How to improve anesthesia and analgesia in small mammals. Vet Clin North Am Exot Anim Pract. 2016;19:361-377 doi:10.1016/j.cvex.2016.01.012. | Morrisey JK, Carpenter JW. Formulary. In: Quesenberry KE, Carpenter JW, eds. Ferrets, Rabbits, and Rodents: Clinical Medicine and Surgery, 4th ed., Elsevier, St. Louis, MO; 2021:620-630. — Source: Carpenter's Exotic Animal Formulary, 6th Ed, p.792 — Carpenter 6th ed, Table 9.4 (Analgesic Agents Used in Rodents), the 2-5 mg/kg SC, IM q4h Most species row bearing superscripts 7 and 130.

· Allweiler SI. How to improve anesthesia and analgesia in small mammals. Vet Clin North Am Exot Anim Pract. 2016;19:361-377 doi:10.1016/j.cvex.2016.01.012. — Source: Carpenter's Exotic Animal Formulary, 6th Ed, p.792 — Carpenter's Exotic Animal Formulary 6th ed, Table 9.4 (Analgesic Agents Used in Rodents).

· Baker TR, Baker BB, Johnson SM, Sladky KK. Comparative analgesic efficacy of morphine sulfate and butorphanol tartrate in koi (Cyprinus carpio) undergoing unilateral gonadectomy. J Am Vet Med Assoc. 2013;243(6):882-890. doi:10.2460/javma.243.6.882 https://pmc.ncbi.nlm.nih.gov/articles/PMC5075523/

· Cantwell SL. Ferret, rabbit, and rodent anesthesia. Vet Clin North Am Exotic Anim Pract. 2001;4:169-191 doi:10.1016/s1094-9194(17)30056-7. — Source: Carpenter's Exotic Animal Formulary, 6th Ed, p.944 — Carpenter's Exotic Animal Formulary 6th ed, Table 11.6 (Analgesic Agents Used in Ferrets).

· Carpenter JW, Hawkins MG. Personal communication; 2020. | Morissey JM, Carpenter JW. Appendix: Formulary. In: Quesenberry KE, OrcuttCJ, Mans C, et al. Ferrets, Rabbits and Rodents: Clinical Medicine and Surgery, 4th ed., Elsevier, St. Louis, MO; 2021:620-630. — Source: Carpenter's Exotic Animal Formulary, 6th Ed, p.863

· Flecknell PA. Analgesia and post-operative care. Laboratory Animal Anaesthesia; 2016:141-192. | Meredith A. BSAVA Small Animal Formulary: Part B: Exotic Pets, British Small Animal Veterinary Association, Quedgeley, Gloucester, UK; 2015. — Source: Carpenter's Exotic Animal Formulary, 6th Ed, p.792 — Carpenter's Exotic Animal Formulary 6th ed, Table 9.4 (Analgesic Agents Used in Rodents).

· Flecknell PA. Analgesia and post-operative care. Laboratory Animal Anaesthesia; 2016:141-192. — Source: Carpenter's Exotic Animal Formulary, 6th Ed, p.792 doi:10.1016/b978-0-12-800036-6.00004-1 — Carpenter's Exotic Animal Formulary 6th ed, Table 9.4 (Analgesic Agents Used in Rodents).

· Innis CJ, Feinsod R, Hanlon J, et al. Coelioscopic orchiectomy can be effectively and safely accomplished in chelonians. Vet Rec. 2013;172:526-531. — Source: Carpenter's Exotic Animal Formulary, 6th Ed, p.255 doi:10.1136/vr.101475 — Carpenter's Exotic Animal Formulary 6th ed, Table 4.6 (Analgesic (Including Antiinflammatory) Agents Used in Reptiles).

· Kinney ME, Johnson SM, Sladky KK. Behavioral evaluation of red-eared slider turtles (Trachemys scripta elegans) administered either morphine or butorphanol following unilateral gonadectomy. J Herp Med Surg. 2011;21:54-62. — Source: Carpenter's Exotic Animal Formulary, 6th Ed, p.256 doi:10.5818/1529-9651-21.2.54 — Carpenter's Exotic Animal Formulary 6th ed, Table 4.6 (Analgesic (Including Antiinflammatory) Agents Used in Reptiles).

· KuKanich B, Wiese AJ. Chapter 11: Opioids. In: Grimm KA, Lamont LA, Tranquilli WJ, Greene SA, Robertson SA, eds. Veterinary Anesthesia and Analgesia, The Fifth Edition of Lumb and Jones. John Wiley & Sons, Inc.; 2015:207-226. (Plumb's Morphine, reference on the CATS intermittent-dosing line) — BSAVA Small Animal Formulary, 10th Ed, Part A, p.291 — Plumb's 10th ed printed p.907, Morphine monograph spanning p.907-911. — Plumb's 10th ed printed p.910, Morphine monograph.

· Leal WP, Carregaro AB, Bressan TF, Bisetto SP, Melo CF, Sladky KK. Antinociceptive efficacy of intramuscular administration of morphine sulfate and butorphanol tartrate in tegus (Salvator merianae). Am J Vet Res. 2017;78(9):1019-1024. doi:10.2460/ajvr.78.9.1019 https://pubmed.ncbi.nlm.nih.gov/28836839/

· Lucas AN, Firth AM, Anderson GA, Vine JH, Edwards GA. Comparison of the effects of morphine administered by constant-rate intravenous infusion or intermittent intramuscular injection in dogs. J Am Vet Med Assoc. 2001;218(6):884-891. doi:10.2460/javma.2001.218.884 — Plumb's 10th ed printed p.907, Morphine monograph spanning p.907-911.

· Mans C, Sladky KK, Schumacher J. General anesthesia. In: Divers SJ, Stahl SJ, eds. Mader's Reptile and Amphibian Medicine and Surgery, 3rd ed., Elsevier, St. Louis, MO; 2019:447-464.; Rooney TA, Eshar D, Gardhouse S, et al. Evaluation of dexmedetomidine-midazolam-ketamine combination administered intramuscularly in captive ornate box turtles (Terrapene ornata ornata). Vet Anaesth Analg; 2021, online 13 August 2021. doi:10.1016/j.vaa.2021.07.002; Sladky KK. Unpublished data; 2017. — Carpenter's Exotic Animal Formulary 6th ed, Table 4.7 (Preferred Injectable Sedation Protocols Used in Select Reptiles.301,400,430).

· Mans C. Clinical technique: intrathecal drug administration in turtles and tortoises. J Exot Pet Med. 2014;23:67-70. — Source: Carpenter's Exotic Animal Formulary, 6th Ed, p.255 doi:10.1053/j.jepm.2013.11.011 — Carpenter's Exotic Animal Formulary 6th ed, Table 4.6 (Analgesic (Including Antiinflammatory) Agents Used in Reptiles).

· Marsh MK, et al. Sedation and Anesthesia of Galapagos (Chelonoidis nigra), Aldabra (Aldabrachelys gigantea), and African Spurred Tortoises (Centrochelys sulcata): A Retrospective Review (2009-2019). Animals. 2021;11(10):2920. doi:10.3390/ani11102920; PMCID: PMC8532946. Table 1. URL: https://pmc.ncbi.nlm.nih.gov/articles/PMC8532946/

· Plumb's Veterinary Drug Handbook, 10th ed (2023), Morphine monograph, DOGS, printed p.910: "Intermittent dosing: 0.5 - 1 mg/kg IM, SC, or IV (slowly)." — Plumb's Veterinary Drug Handbook, 10th ed (2023) — Plumb's 10th ed printed p.907, Morphine monograph spanning p.907-911.

· Plumb's Veterinary Drug Handbook, 10th ed (2023), Morphine monograph, printed p.910, DOGS - Analgesia (extra-label), item c) Epidural. -

· Ramsey I, ed. BSAVA Small Animal Formulary, 10th ed. Part B: Exotic Pets. Gloucester: British Small Animal Veterinary Association; 2023. p.210.

· Ramsey I, ed. BSAVA Small Animal Formulary, 10th ed. Part B: Exotic Pets. Gloucester: British Small Animal Veterinary Association; 2023. p.210. — CORROBORATED 2026-08-06 by independent literature: Use of a shuttle box model to assess the behavioral and analgesic effects of opioid injections in goldfish (Carassius auratus). (American journal of veterinary research, 2024). doi:10.2460/ajvr.24.06.0172. https://doi.org/10.2460/ajvr.24.06.0172. The paper reports this drug at this dose in this species: ". First, opioid effects were tested in a shuttle box without painful stimulus. Fish were injected 5 […]". This is a second source alongside the book already cited; it corroborates the figure and does not by itself establish that the dose is correct. ROUTE DIFFERS: this rule is I.M. but the sentence quoted describes IM. The dose figure is corroborated; the route is not.

· Ritchie BW, Harrison GJ. Formulary. In: Ritchie BW, Harrison GJ, Harrison LR, eds. Avian Medicine: Principles and Applications; Wingers Publishing, Lake Worth, FL; 1994:457-478. — Source: Carpenter's Exotic Animal Formulary, 6th Ed, p.644 — Carpenter's Exotic Animal Formulary 6th ed, Table 6.4 (Chemical Restraint/Anesthetic/Analgesic Agents Used in Backyard Poultry,).