Amitriptyline antidepressant drug. Bottle of a liquid solution of the antidepressant drug amitriptyline, together with a plastic spoon for oral doses. Amitriptyline is a member of the tricyclic antidepressant (TCA) group of drugs. These work by increasing the levels of the neurotransmitters serotonin and noradrenaline in the brain. Like many TCAs, this drug can produce unpleasant side effects, including a dry mouth, drowsiness (warning given on label), irregular heartbeat and low blood pressure. This is a sugar- free version of the drug. Photographed in the UK.