Amitriptyline Tablet

Amitriptyline HCl is an antidepressant with sedative effects. Its mechanism of action in man is not known. It is not a monoamine oxidase inhibitor and it does not act primarily by stimulation of the central nervous system.

Amitriptyline inhibits the membrane pump mechanism responsible for uptake of norepinephrine and serotonin in adrenergic and serotonergic neurons. Pharmacologically, this action may potentiate or prolong neuronal activity since reuptake of these biogenic amines is important physiologically in terminating transmitting activity. This interference with reuptake of norepinephrine and/or serotonin is believed by some to underlie the antidepressant activity of Amitriptyline.

Uses

Amitriptyline is used for depressive illness, particularly with anxiety and nocturnal enuresis in children.

Amitriptyline is also used to associated treatment for these conditions: Acute Depression, Anorexia Nervosa (AN), Attention Deficit Hyperactivity Disorder (ADHD), Bulimia Nervosa, Depression, Diabetic Neuropathies, Insomnia, Irritable Bowel Syndrome (IBS), Major Depressive Disorder (MDD), Migraine, Moderate Depression, Neuropathic Pain, Nocturnal Enuresis, Severe Depression, Sleep disorders and disturbances, Tension Headache, Moderate Agitation, Moderate Anxiety, Severe Anxiety, Severe agitation

Trade Name Amitriptyline
Generic Amitriptyline
Other Names Amitriptilina, Amitriptylin, Amitriptyline, Amitriptylinum
Weight 10mg, 25mg, , Amitriptyline Hydrochloride 25mg
Type Tablet
Formula C20H23N
Weight Average: 277.4033
Monoisotopic: 277.183049741
Protein binding

Very highly protein bound (95%) in plasma and tissues .

Therapeutic Class Tricyclic Anti-depressant
Manufacturer Glaxosmithkline, Brown & Burk Uk Ltd, Indofarma, Yarindo Farmatama, Ecomed Pharma Limited
Available Country Bangladesh, United Kingdom, United States, Indonesia, Nigeria
Last Updated: June 23, 2021 at 11:16 am

Dosage

Amitriptyline dosage

Depression :

  • Adults: Initially 50-70 mg a day in divided dose or as a single dose at night at bed time.
  • Elderly and adolescents: 25-50 mg daily in divided doses or as single dose at bed time. Dose can be increased gradually as necessary to a maximum of 150-200 mg. Usual maintenance dose is 50-100 mg daily.

Nocturnal enuresis:

  • 6-10 years: 10-20 mg at bed time.
  • 11-16 years: 25-50 mg at bed time for up to 3 months and gradually withdrawn.

Side Effects

  • Cardiovascular reactions: Hypotension, syncope, postural hypotension, hypertension, tachycardia, palpitations, myocardial infarction, arrythmias, and heart block stroke.
  • CNS and neuromuscular: Confusional states, disturbed concentration disorientation, delusions, and hallucinations.
  • Anticholinergic: Dry mouth, blurred vision, mydriasis, increased intraoccular pressure, hyperplasia.
  • Allergic: Skin rash, urticaria, and photosensitization.
  • Haematological: Bone-marrow depression including agranulocytosis, leukopenia, eosinophilia, and thrombocytopenia.
  • Gastrointestinal: Nausea, epigastric distress, vomiting anorexia, diarrhoea.
  • Endocrine: Testicular swelling, gynaecomastia; breast enlargement, galactorrhoea.
  • Other reaction: Dizziness, weakness, fatigue, headache, weight loss

Precaution

Schizophrenic patients may develop increased symptoms of psychosis; patients with paranoid symptomatology may have an exaggeration of such symptoms. Depressed patients, particularly those with known manic-depressive illness, may experience a shift to mania or hypomania. In these circumstances the dose of Amitriptyline may be reduced or a major tranquilizer such as perphenazine may be administered concurrently.

The possibility of suicide in depressed patients remains until significant remission occurs. Potentially suicidal patients should not have access to large quantities of this drug. Prescriptions should be written for the smallest amount feasible.

Concurrent administration of Amitriptyline hydrochloride and electroshock therapy may increase the hazards associated with such therapy. Such treatment should be limited to patients for whom it is essential.

When possible, the drug should be discontinued several days before elective surgery. Both elevation and lowering of blood sugar levels have been reported. Amitriptyline hydrochloride should be used with caution in patients with impaired liver function.

Interaction

Monoamine oxidase inhibitors can potentiate the effects of Amitriptyline.

Anticholinergic agents: Amitriptylin should not be given with symptomatic agents such as adrenaline, epinephrine, isoprenaline, noradrenaline.

CNS depressant: Amitriptyline may enhance the response to alcohol, barbiturates.

Cemitidine: Cemitidine is reported to reduce hepatic metabolism of certain tricyclic antidepressants.

Food Interaction

  • Avoid alcohol.
  • Avoid St. John's Wort.
  • Limit caffeine intake.
  • Take with food. Food reduces irritation.

Volume of Distribution

The apparent volume of distribution (Vd)β estimated after intravenous administration is 1221 L±280 L; range 769-1702 L (16±3 L/kg) . It is found widely distributed throughout the body . Amitriptyline and the main metabolite nortriptyline pass across the placental barrier and small amounts are present in breast milk .

Half Life

The elimination half-life (t1⁄2 β) amitriptyline after peroral administration is about 25 hours (24.65 ± 6.31 hours; range 16.49-40.36 hours) .

Clearance

The mean systemic clearance (Cls) is 39.24 ± 10.18 L/h (range: 24.53-53.73 L/h) . No clear effect of older age on the pharmacokinetics of amitriptyline has been determined, although it is possible that clearance may be decreased .

Pregnancy & Breastfeeding use

Pregnancy Category C. Amitriptyline is not recommended during pregnancy, especially during the first and third trimester because the safety of Amitriptyline has not been established yet. 

Amitriptyline is detectable in breast milk. Because of the serious adverse reactions in infants from Amitriptyline, a decision should be made whether to continue breast feeding or discontinue the drug

Contraindication

Amitriptyline is contraindicated in myocardial infarction; arrythmias, particularly heartblock of any degree; mania; severe liver disease. Initially sedation may effect the ability to drive or operate machinery. It should be used with caution in patients with a history of epilepsy, glaucoma, urinary retention, prostatic hypertrophy, constipation, cardiac disease, diabetes, pregnancy, hepatic impairment, thyroid disease, increased intraoccular pressure, psychoses (may aggravate mania).

Storage Condition

Keep containers well closed and stored below 25˚ C, protected from light.

Amitriptyline contains Amitriptyline see full prescribing information from innovator Monograph