ExoticRx · exoticrx.com/drugs/methadone
US brand names:Methadose
Methadone is dosed at 0.1–0.3 mg/kg IM q4-6h in cats, per Verified against Plumb's Veterinary Drug Handbook, 10th Ed, p.872 (2026-08-01).. 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 Cat (Domestic) drugsAll Dog (Domestic) 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 2 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). |
| 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. doi:10.1111/j.1467-2995.2012.00744.x — Verified against Plumb's Veterinary Drug Handbook, 10th Ed, p.871 (2026-08-01). |
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