Amitriptyline
Antidepressant · Tricyclic antidepressant (TCAD)
Indications
Depression in adults. Enuresis in children.
Dosage
Adults: Usually 75 mg daily in divided doses increasing if required to 150 mg daily. Maintenance, 50-100 mg daily usually as a single dose at bedtime. Elderly: 50 mg daily in divided doses or as a single dose at bedtime. Children: Depression: 16-18 yr, 10-25 mg 3 times daily (total daily dose may alternatively be given as a single dose at bedtime) increased gradually as necessary to 150-200 mg daily.
Adverse Effects
Anticholinergic effects, (e.g. dry mouth, blurred vision). Tinnitus, confusion, aggression, decreased libido, agitation, somnolence, dizziness, dysarthria, attention disturbance, dysgeusia, paraesthesia, palpitations, drowsiness, headache, tremor, ataxia, seizures, movement disorders, dyskinesias. Cardiovascular effects, e.g. hypotension, tachycardia, syncope, conduction disturbances, arrhythmias, GI upset, taste disturbance. Blood dyscrasias, sweating, allergic skin reactions, weight changes, testicular swelling, gynaecomastia, changes in blood sugar concentrations, hyponatraemia. Behavioural disturbances. Hepatic impairment, jaundice.
Risk Factor (Pregnancy/Lactation)
Pregnancy: Risk cannot be ruled out. Lactation: Contraindicated or not recommended. Contraindications: Arrhythmias (particularly heart block), recent MI, coronary artery insufficiency, severe liver disease, mania. Porphyria. Precautions: Hepatic impairment (contraindicated if severe). History of epilepsy, urinary retention, glaucoma, or increased intra-ocular pressure, prostatic hypertrophy, risk factors for narrow angle glaucoma, increased IOP, pyloric stenosis, paralytic ileus, diabetes. Cardiovascular disorders, hyperthyroidism; monitor carefully. Pheochromocytoma. History of mania or psychosis, concurrent ECT. Anaesthesia, Reports of QT prolongation and arrhythmia. Monitor for suicidal ideation. Poor metabolisers of CYP2D6 or CYP2C19. Elderly. withdraw gradually.
Interactions
With or within 14 days of MAOIs. Other antidepressants, St. John's Wort, tramadol, drugs that prolong the QT interval (e.g. antiarrhythmics), moxifloxacin, anticonvulsants, diltiazem, verapamil, other antihypertensives, antipsychotics, sotalol, dopaminergics, artemether/lumefantrine, sibutramine, anticholinergics, sympathomimetics, oral anticoagulants, cimetidine, adrenergic neuron blockers (e.g., clonidine), diuretics, SSRIs, tramadol, azole antifungals, terbinafine, alcohol, CYP2D6 inhibitors, oral contraceptives, rifampicin, linezolid, disulfiram.
Advice to Patient
Take with or without meals immediately before bedtime. Contact prescriber if there is headache, agitation, change in memory, lack of sleep, nervousness, restlessness, change in vision, chest pain, palpitations, irregular heartbeat, muscle cramps, weakness, tremors, rigidity, ringing in ears. Empty bladder before taking medication. Limit alcohol and caffeine intake. Avoid taking grapefruit juice. Take sufficient amount of fluids (2-3 litres per day) to maintain hydration, unless restricted by the prescriber. Change position slowly from sitting or lying to standing. Avoid direct sunlight. Use sunscreen, wear proper clothing and eyewear to prevent photosensitivity. On start of therapy or change of dosage, patient should be watched carefully for suicidal tendency by caregiver or family.
Pharmacokinetics
Onset of action: Individual responses may vary; however, 4 to 8 weeks of treatment are needed before determining if a patient with depression is partially or non-responsive; similarly 8 to 12 weeks are required for an adequate migraine prophylaxis trial; desired therapeutic effect (for analgesia) may take as long as 1 to 3 weeks. Absorption: Rapid, well absorbed. Metabolism: Rapid. Bioavailability: Approx. 43% to 46%. Half-life elimination: Approx. 13 to 36 hours. Time to peak, serum: Approx. 2 to 5 hours. Excretion: Urine (glucuronide or sulfate conjugate metabolites: 18% as unchanged drug) Feces (small amounts).
Unlicensed Use
Children: Neuropathic pain: 2-12 yr, initially 200-500 mcg/kg, max 10 mg once daily at night, increased if necessary, max 1 mg/kg twice daily on specialist advice; 12-18 yr, initially 10 mg once daily at night, increased gradually if necessary to usual dose 75 mg at night.
Brands with this active ingredient
Compiled by Healify Pharmacy from published drug references. How we compile it →
Always consult a pharmacist or doctor.