ExoticRx · exoticrx.com/drugs/methadone
US brand names:Methadose
Methadone is dosed at 3–5 mg/kg SC, IM q24h in red-eared sliders, per Sladky KK, Mans C. Clinical analgesia in reptiles. J Exot Pet Med. 2012;21:17-32. — Source: Carpenter's Exotic Animal Formulary, 6th Ed, p.255 — Carpenter's Exotic Animal Formulary 6th ed, Table 4.6 (Analgesic (Including Antiinflammatory) Agents Used in Reptiles). The copy held is an ebook conversion with no printed page numbers, so the table — not the page — is the citable location. — SOURCE EDITION: Carpenter's Exotic Animal Formulary — ISBN 9780323833929, https://openlibrary.org/isbn/9780323833929. Verify against current literature before clinical use.
Full mu-opioid receptor agonist providing analgesia. Also antagonizes NMDA receptors and inhibits serotonin/norepinephrine reuptake, contributing to multimodal analgesia.
Respiratory depression. Bradycardia. No histamine release (advantage over morphine). NMDA antagonism provides wind-up prevention. Controlled substance (Schedule II). Dogs and cats.
Species references:All African Pygmy Hedgehog drugsAll Cat (Domestic) drugsAll Dog (Domestic) drugsAll Ferret drugsAll Mouse drugsAll Pet Rat drugsAll Red-eared Slider drugsAll Sugar Glider drugs
Controlled substance in the US
Controlled-drug status and schedules differ by country — check your local scheduling rules.
Each ExoticRx dose rule is graded by the strength of its primary evidence — see the editorial process.
A dog/cat sample is shown here. Cited dosing for all 8 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 |
|---|---|---|---|---|---|
| Cat (Domestic) | IM | 0.1–0.3 mg/kg | q4-6h | Strong | Verified against Plumb's Veterinary Drug Handbook, 10th Ed, p.872 (2026-08-01). — Plumb's 10th ed (held) printed p.842, Methadone monograph spanning p.842-845; page located 2026-08-05 from the book's own running heads, verified to name the drug in its body text. — SOURCE EDITION: Plumb's Veterinary Drug Handbook — ISBN 9781394172207, https://openlibrary.org/isbn/9781394172207 |
| Dog (Domestic) | IV | 0.1–0.5 mg/kg | q4-6h | Strong | Comfortan 10 Mg/Ml Solution for Injection for Dogs and Cats [UK Package Insert]. Eurovet Animal Health; 2005.; Methodyne Injection [Australian Package Insert]. Jurox; 2016.; Bosmans T, Piron K, Oosterlinck M, et al. Comparison of analgesic efficacy of epidural methadone or ropivacaine/methadone with or without pre-operative oral tepoxalin in dogs undergoing tuberositas tibiae advancement surgery. Vet Anaesth Analg. 2012;39(6):618-627. — Verified against Plumb's Veterinary Drug Handbook, 10th Ed, p.871 (2026-08-01). — Plumb's 10th ed (held) printed p.842, Methadone monograph spanning p.842-845; page located 2026-08-05 from the book's own running heads, verified to name the drug in its body text. — SOURCE EDITION: Plumb's Veterinary Drug Handbook — ISBN 9781394172207, |
Upgrade to Pro or Student to unlock the full dose ranges and frequency for every species. The drug's mechanism, warnings, indications, and cited sources are free to read.
View PlansSource citations and evidence levels available on the live page. Reference only — verify against current literature before clinical use.