Being an anti-depressant medication, amitriptyline UK forms part of a group of medicines known as selective serotonin reuptake inhibitors (or SSRIs). These medications work by affecting the serotonin levels in the brain. The benefits listed below indicate how serotonin is involved in the mechanism of action of this pain tablet: • Mood enhancement: You can use amitriptyline for anxiety because the medication helps improve your mood. This treatment increases the amount of serotonin in the body by