Tramadol has low affinity for μ- and κ-opioid receptors and inhibits the reuptake of both norepinephrine and serotonin (5-hydroxytryptamine) neurotransmitters. It stimulates the dopamine (D2) receptors and also inhibits the gamma amino butyric acid release in central nervous system.

Does tramadol affect serotonin levels?

Tramadol increases the concentration of serotonin in the synapses between the serotonergic neurons found in the brain stem. This extra serotonin causes some of the positive effects of the medication, such as pain relief.

Does tramadol increase dopamine release?

Tramadol acts on opioid receptors and increases the levels of dopamine present in the brain like other opioids, but it also inhibits norepinephrine and serotonin from being reabsorbed.