Antidepressants have analgesic effects in addition to antidepressant effects and are used to treat a variety of chronic pain syndromes. Such drugs include tricyclic antidepressants and monoamine oxidase inhibitors. The analgesic mechanism of tricyclic antidepressants is by blocking the reuptake of norepinephrine and 5-HT, which can act at the central and cremasteric levels, affecting the endorphin-mediated pain-regulating pathway to produce analgesia. These drugs are completely absorbed orally and are mainly metabolized by the liver, with a first-pass effect, and the blood concentration reaches its peak 2-8 hours after administration. Monoamine oxidase inhibitors inhibit monoamine oxidase in the central nervous system, adrenergic nerve endings, liver, and intestines, blocking the oxidative deamination of monoamine neurotransmitters at the synapse and leading to increased levels of norepinephrine and 5-HT in the plasma of nerve endings. It should be noted that antidepressants are not preferred in the treatment of pain, and the choice should be based on a combination of both patient needs and drug side effects.