**4.1. Serotonin and noradrenalin reuptake inhibitors**

TCAs exerting inhibition of 5‐HT and NA reuptake, such as amitriptyline, appear to be effec‐ tive analgesics. The pain relief from amitriptyline is generally moderate and is accompanied by side effects. TCAs block receptors of other neurotransmitters: histamine H1, muscarinic and nicotinic cholinergic and alpha‐adrenergic. These actions explain certain side effects such as dry mouth, constipation, sedation, postural hypotension, etc [3]. For this reason, TCAs must be used with caution in patients with a history of cardiovascular disease, glaucoma, urinary retention and autonomic neuropathy, and with extreme caution in elderly patients.

Venlafaxine and duloxetine exhibit 5‐HT and NA reuptake inhibition, but unlike amitripty‐ line and other TCAs, they lack significant affinity for muscarinic, histamine H1 and alpha‐1 adrenergic receptors.
