Synergistic antinociceptive interaction between palmitoylethanolamide and tramadol in the mouse formalin test
Laboratory studyOther animalsWith tramadol
This study tested palmitoylethanolamide together with tramadol. Its results cannot be assigned to palmitoylethanolamide alone. More combination studies.
- Design
- Laboratory study
- Subjects
- Mice given an intraplantar formalin injection to produce pain
- Dose used in the study
- PEA (0.1-56.2 micrograms per paw) and tramadol (1-56.2 micrograms per paw), injected into the paw, alone and in a fixed 1:1 combination
- Duration
- Not stated in the abstract
- What was measured
- Pain response in the formalin test, using isobolographic analysis to test for synergy, and involvement of opioid receptors, TRPV1 channels and PPAR-alpha; sedation was also assessed
What the authors reported
PEA and tramadol combined produced a synergistic reduction in pain response: the effective combined dose (9.5 micrograms per paw) was lower than the dose calculated by adding the two drugs' individual effects (24.8 micrograms per paw). The combination's antinociceptive effect involved opioid receptors, TRPV1 and PPAR-alpha, and caused less sedation than either drug alone.
Limits of this study
A mouse model of formalin-induced pain; it cannot show effect in people. Funding and conflicts not stated in the abstract.
Source
PubMed 26297302 · doi:10.1016/j.ejphar.2015.08.025
Entry checked against the abstract on PubMed on 2026-09-22. The dose shown is the dose the researchers used. It is not a recommendation. How to read this page.