Acts as an immunomodulator on non-opioid innate immune pathways, inducing stereoselective microglial quiescence via its effect on the TLR (Toll-like receptor)-4 pathway. An additional mechanism of action involves transient opioid receptor blockade, leading to a homeostatic neuroendocrine response that results in a transient increase in the endogenous opioid receptor tone (impact may be marginal in the opioid tolerant palliative advanced cancer population).

At low doses, receptor occupancy lasts a few hours only, causes partial blockade, and fails to suppress endogenous opioid activity fully.

Is known to precipitate withdrawal and reduce analgesic efficacy, making its use in the palliative setting challenging.

This drug may have a role in the management of cancer-related fatigue, neuroinflammatory pain, chemotherapy-induced peripheral neuropathy and cancer-cachexia-associated inflammation.

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