Tramadol

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Can I ask if anybody is using tramadol orally as a method of pain relief/ medium term analgesia? I have a researcher working on mice, looking at an induced inflammation licence. They plan on using buprenorphine at the beginning of the study but as duration of action is only 8 hours they would like to add sustained analgesia over the seven days of the study.

I have looked at some papers on the administration of oral tramadol at dose of 1g/litre in drinking water. Does anybody have any experience of using tramadol orally?

My reading of the literature suggests that at high dose (1g/litre) the solution tastes bitter and water intake is reduced per animal, also read that 1g/litre tramadol in water is close to toxic dose.

We worked repeatedly with Tramadol. And the lower dosages seem to be OK for some interventions and better than the higher ones (reduce oral intake, side effects > nausea?).

See for example:

Evangelista-Vaz, Rocio, et al. "Analgesic efficacy of subcutaneous–oral dosage of tramadol after surgery in C57BL/6J mice." Journal of the American Association for Laboratory Animal Science 57.4 (2018): 368-375.

Vaz, Rocío Evangelista, et al. "Preliminary pharmacokinetics of tramadol  hydrochloride after administration via different routes in male and  female B6 mice." Veterinary anaesthesia and analgesia 45.1 (2018): 111-122.

Jirkof, Paulin, et al. "Administration of Tramadol or Buprenorphine via  the drinking water for post-operative analgesia in a mouse-osteotomy  model." Scientific reports 9.1 (2019): 1-16.

Jirkof, Paulin, Margarete Arras, and Nikola Cesarovic. "Tramadol:  Paracetamol in drinking water for treatment of post-surgical pain in  laboratory mice." Applied Animal Behaviour Science 198 (2018): 95-100.

Nevertheless, Tramal is quite short acting and not useful (alone) for more severe pain. Therefore, one has to consider a switch carefully.

Try the oral solution yourself, it tastes a bit bitter and minty. We were very successful in masking the taste with sweet Dafalgan syrup, which mice like.