Amitriptyline
Amitriptyline is a tricyclic antidepressant that blocks the reuptake of serotonin and noradrenaline while also blocking histamine, muscarinic and alpha-adrenergic receptors. That broad receptor activity explains both its sedating effect and its dry-mouth side effects. It is used for depression, neuropathic pain, migraine prevention and sleep problems, with the pain and sleep uses relying on smaller amounts than the psychiatric ones.
It is taken at bedtime because drowsiness is expected, and that drowsiness can carry into the next morning, so driving and machine work call for caution until the effect is known. Food makes no difference to timing. Dry mouth, constipation and blurred vision come from the anticholinergic action and usually ease over weeks. Fluconazole and terbinafine slow its breakdown in the liver and push blood levels up, while tramadol adds serotonin effects and lowers the seizure threshold. The drug can prolong the QT interval on the ECG, which matters more when other QT-prolonging medicines are in use, and it should not be stopped abruptly.
See a doctor for fainting, palpitations or an irregular heartbeat, for confusion or difficulty passing urine, and for agitation with fever, shivering or muscle twitching.
Reference information, not medical advice. Discuss any change with your doctor.