Tramadol
Tramadol is a centrally acting analgesic with opioid and monoaminergic actions. Its veterinary applications involve selected acute or chronic pain states, often within multimodal treatment. Species differ substantially in production and persistence of the opioid-active metabolite, which contributes to variation in clinical response. Evidence for benefit is indication- and species-dependent.
Group
Centrally acting analgesic
Mechanism of Action
Tramadol weakly stimulates mu-opioid receptors and inhibits reuptake of serotonin and norepinephrine, modifying central and descending pain pathways. Its metabolite O-desmethyltramadol has stronger mu-receptor activity than the parent drug. Cats and dogs differ in metabolite exposure, so opioid and monoaminergic contributions to analgesia vary between species. These differences help explain inconsistent clinical effects.
Dose Rates
Dogs
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Pain | 5 mg/kg | PO | Every 6–8 h | |
| Pain | 4 mg/kg | IV | Every 6–8 h | |
| Epidural analgesia | 1–2 mg/kg | EPIDURAL | Diluted in saline; reported effect may largely reflect systemic absorption. | |
| Pain higher-dose alternative | 10 mg/kg | PO | Every 6–8 h | Reported for poor response, but efficacy at this exposure is unestablished; use multimodal assessment. |
| Chronic pain | 2–5 mg/kg | PO | Every 8–12 h |
Cats
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Pain — Initial | 2 mg/kg | PO | Every 8–12 h | Increase gradually if needed. |
| Pain — Maintenance | 4 mg/kg | PO | Every 8–12 h | |
| Pain | 2 mg/kg | IV | Injectable amount reported; repeat interval not specified for this IV line. | |
| Pain | 2–4 mg/kg | SC | Every 8 h | |
| Epidural analgesia | 1–2 mg/kg | EPIDURAL | Diluted in saline; reported effect may largely reflect systemic absorption. | |
| Osteoarthritis pain | 2 mg/kg | PO | Every 12 h | Up to 5 days; Higher doses were less effective in the reported clinical study. |
| Pain | 1–2 mg/kg | PO | Every 12 h | |
| Chronic pain | 1–4 mg/kg | PO | Every 8–12 h |
Horses
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Pain | 2 mg/kg | IV | Every 6–12 h | Slow IV over about 10 minutes. Do not exceed 2 mg/kg per administration; interval is suggested rather than established. |
| Pain | 4–5 mg/kg | PO | Every 6–12 h | Do not exceed 5 mg/kg; interval suggested rather than established. |
| Epidural analgesia | 1–2 mg/kg | EPIDURAL | Diluted in saline; reported effect may largely reflect systemic absorption. | |
| Laminitis pain adjunct | 5 mg/kg | PO | Every 12 h | Limited efficacy alone; improved response reported with ketamine infusion 0.6 mg/kg/hour in a combined protocol. |
Indications
- Treatment of selected mild-to-moderate acute pain in cats or dogs, often as part of a multimodal plan, with variable clinical response.
- Adjunctive management of selected chronic pain states in cats, with limited and condition-specific evidence.
- Adjunctive management of selected canine chronic pain where an individualized response is documented; evidence for oral monotherapy in osteoarthritis is poor.
- Selected specialist analgesic use in other veterinary species, with limited species-specific evidence.
Contraindications
- Seizure disorders or renal disease require caution.
Interactions
- Other CNS depressants and serotonergic drugs can increase adverse effects; metabolic inhibitors alter parent and active metabolite exposure.
Adverse effects
- Sedation; feline vomiting, dysphoria, mydriasis or excitement; equine agitation, tremor, sweating, tachycardia and ataxia, especially after rapid IV use.
Toxicity
High doses can cause seizures; naloxone only partly reverses adverse effects. Overdose can produce CNS depression or serotonin toxicity, including agitation, tremor, tachycardia and seizures. Naloxone may only partly reverse effects and can potentially increase seizure risk; airway and seizure management are central.
Preparations
| Preparation | Form | Strength | Route |
|---|---|---|---|
| Tramadol immediate-release 50 mg | Tablet | 50 mg / tablet | PO |
| Tramadol injection 50 mg/mL 50 mg/mL injectable presentation. Epidural use requires separately confirmed preservative and excipient suitability; this preparation is not automatically linked to epidural protocols. | Injection | 50 mg / mL | IV, IM, SC |
Monitoring and Administration
Assess actual analgesic response; canine clinical efficacy is inconsistent and human extended-release exposure cannot be assumed suitable. Give equine IV doses over about 10 minutes.
Protect from light; reported 10 mg/mL sterile-water preparation retained potency refrigerated but flavored compound stability is not established.
Equine laminitis combination study used tramadol 5 mg/kg orally twice daily for 7 days with ketamine 0.6 mg/kg/hour IV for 6 hours/day during the first 3 days. These timed combined infusions are not continuous all-day ketamine instructions.