Amitriptyline

Systematic (IUPAC) name
3-(10,11-dihydro-5H-dibenzo[[a,d]] cycloheptene-5-ylidene)-N, N-dimethyl-1-propanamine

Identifiers: CAS number 50-48-6; ATC code N06AA09; PubChem 2160; DrugBank APRD00227.
Chemical data: Formula C20H23N;
Mol. mass 277.403 g/mol.
Pharmacokinetic data: Bioavailability 40%; Metabolism Hepatic
Half life 12-24 hours; Excretion Renal.
Therapeutic considerations: Pregnancy cat. D(US);
Legal status Unscheduled(AU) POM(UK); Routes Oral.

Amitriptyline (or Amitryptyline) hydrochloride (sold as Elavil, Tryptanol, Endep, Elatrol, Tryptizol, Trepiline, Laroxyl) is a tricyclic antidepressant drug. It is a white, odorless (but tastes like licorice), crystalline compound which is freely soluble in water; it is usually dispensed in tablet form. In terms of its mechanism of action, amitriptyline inhibits serotonin and noradrenaline reuptake almost equally.

Uses:
Approved: Amitriptyline is approved for the treatment of endogenous depression and involutional melancholia (depression of late life, which is no longer seen as a disease in its own right.) Adult typical dosages are 25 to 150 mg daily, with half this initially for elderly or adolescents.
It may also be used to treat nocturnal enuresis (bed wetting). Children between the ages of 7 to 10 years having a dose of 10 to 20 mg, older children 25 to 50 mg at night. It should be gradually withdrawn at the end of the course, which overall should be of no more than 3 months.
In some European countries it is also approved as prophylaxis for patients with frequent migraines (usually 25 to 75 mg).
Unapproved/Off-Label/Investigational: Amitriptyline may be prescribed for other conditions such as insomnia, migraine, rebound headache, chronic pain, postherpetic neuralgia (persistent pain following a shingles attack), fibromyalgia, vulvodynia, interstitial cystitis, irritable bowel syndrome, diabetic peripheral neuropathy, neurological pain, and painful paresthesias related to multiple sclerosis and as a preventative (prophylaxis) for patients with frequent migraines. It is also used in small (10 mg) doses to act as a painkiller and ease the effects of Carpal Tunnel Syndrome. Typically lower dosages are required for pain modification of 10 to 50 mg daily.
Amitriptyline in very small doses (5 mg a day) is also sometimes prescribed to help ease the symptoms of chronic fatigue syndrome. It is thought to help combat symptoms of insomnia primarily, in addition to other selected symptoms of the affliction.
A randomized controlled trial published in June 2005 found that amitriptyline was effective in functional dyspepsia refractory to famotidine and mosapride combination therapy.

Side effects: Common side effects of using amitriptyline are extreme weight gain, drowsiness, nervousness, dizziness, and insomnia. Some rare side effects include tinnitus, hypotension, mania, psychosis, anticholinergic effects, heart block, arrhythmias, extrapyramidal symptoms, depression, and hepatic toxicity.
Overdose: The symptoms and the treatment of an overdose are largely the same as for the other tricyclic antidepressants.