Update (June 19, 2026): Tramadol-Dipyrone Combination Outperforms Monotherapy for Feline OVH Analgesia - RCT

TL;DR. A 2026 RCT found that a fixed-dose oral tramadol-dipyrone combination provided superior postoperative analgesia in cats undergoing ovariohysterectomy versus either drug alone, with less rescue analgesia and fewer adverse effects including markedly lower sialorrhoea rates.

What just dropped

• Fantoni et al. 2026 (Front Vet Sci, open access; PMID 41737681) randomised 36 female cats undergoing ovariohysterectomy to tramadol+dipyrone combination (GTD, n=12), tramadol alone (GT, n=12), or dipyrone alone (GD, n=12), all administered orally every 12 h for 5 days. (https://europepmc.org/articles/PMC12927265)
• Rescue analgesia (morphine): GTD required less rescue medication (1/12) compared to GT (4/12) and GD (5/12).
• Cortisol: concentrations were significantly reduced in GTD at 4 h post-op compared to GT and GD (p significant).
• Sialorrhoea: markedly lower in the combination group - GTD 2/12 vs GT 9/12 and GD 12/12.
• No cardiovascular or respiratory depression was observed in any group.
• The combination used was Sindolor Cats tablets; Fantoni et al. 2026 administered dipyrone and tramadol at per-label study doses orally every 12 h for 5 days.

Context

Tramadol's clinical utility in cats has been debated because of species differences in opioid receptor distribution and metabolism, and a relatively short duration of action. Dipyrone (metamizole) provides antipyretic, analgesic, and antispasmodic effects via mechanisms including PGE2 inhibition. The combination in a single oral tablet addresses the challenge of reliable home analgesia administration in cats, where pill compliance and palatability are barriers.

The study used sacrococcygeal epidural lidocaine as the baseline intraoperative analgesic in all groups, making the comparison a test of adjunctive oral analgesia. The Feline Grimace Scale and the CMPS-Feline were used to score pain. The use of cortisol as a corroborating objective measure strengthens the primary outcome.

What this changes in maropitant-dogs-cats-vomiting (https://www.thevoyage.ai/forvets/knowledge/maropitant-dogs-cats-vomiting)

This study is directly relevant to the broader feline perioperative analgesia and antiemetic discussion. The high sialorrhoea rate with tramadol monotherapy (9/12 cats) is a clinically important tolerability signal — opioid-induced nausea/salivation in cats is a known challenge and supports the use of antiemetics (including maropitant) as part of multimodal perioperative protocols when opioids are used. The combination approach significantly attenuated this problem.

References

1. Fantoni DT, Yazbek KVB, de Lima IT, et al. Analgesic efficacy of oral tramadol-dipyrone combination in cats undergoing ovariohysterectomy. Front Vet Sci. 2026;13:1773463. https://europepmc.org/articles/PMC12927265
2. Golbeli Bedir A, Yanmaz LE, Okur S, et al. The Effect of Maropitant, Ondansetron and Metoclopramide on Dexmedetomidine-Induced Vomiting in Cats. Vet Med Sci. 2025;11(1):e70152. https://europepmc.org/articles/PMC11720719

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• Maropitant (Cerenia) for Vomiting in Dogs and Cats: Clinical Evidence
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