Effects of Dexmedetomidine Alone and Combined with Tramadol on Intraocular Pressure, Pupil Size, and Tear Production in Cats: A Randomized Controlled Study

This present study was designed to evaluate the impact of intramuscular dexmedetomidine, alone or combined with subcutaneous tramadol, on intraocular pressure (IOP), pupil size (PS), and tear secretion (TS) in healthy cats. Thirty healthy cats (n=30) were randomly assigned to two groups (n=15/group). Cats received either dexmedetomidine alone (Dex; 25 µg/kg IM) or dexmedetomidine plus tramadol (Dex-Tra; tramadol 2 mg/kg SC + dexmedetomidine 25 µg/kg IM). IOP, PS, and TS were recorded at baseline (T0) and 5, 15, and 30 minutes post-administration (T5, T15, T30). Within the Dex group, IOP decreased significantly from T0 to T30, and PS increased from T5 to T15, returning to baseline by T30 (p0.05). Both protocols reduced TS over time. Dexmedetomidine alone produced ocular hypotension and a transient increase in PS; co-administration with tramadol attenuated these effects. As both regimens decreased tear secretion, clinicians should consider potential impacts on tonometry, ocular surface integrity, and perioperative ophthalmic management when selecting sedation protocols.