Table 4. Dosage and pharmacological characteristics of tramadol and tapentadol [81,91,114].

Drug	Species	Doses	Route	Mechanism of action	Adverse effects
Tramadol	Dogs	4–10 mg/kg/6–8 h	IV, IM, PO	Agonism to μ-receptors Inhibits monoamine reuptake (NE and 5-HT)	Tremors, myoclonus, tachycardia, agitation, excitement, hypertension, and seizures (signs of serotonin toxicity)
	Cats	1–4 mg/kg/12–24 h	IM, IV, PO
Tapentadol*	Dogs	2–30 mg/kg	IV, PO	μ-Opioid receptor agonist NRI	Salivation, agitation, panting, mydriasis, euphoria, and sedation
	Cats	5–10 mg/kg q 12 h	IV, IM, PO, SC

PO = oral.

^*doses taken from the available literature.