Amitriptyline

Amitriptyline-2D-skeletal.png
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
ChemSpider 2075
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, Saroten, Triptyl) 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[1] and noradrenaline reuptake almost equally.

Contents

Uses

Amitriptyline is now used in the United States and UK to prevent migranes and vaginal swelling only in very small doses.

Approved

Amitriptyline is approved most commonly for the treatment of depression (clinical/endogenous depression, also 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 It should be gradually withdrawn at the end of the course, which overall should be of no more than 3 months.[2]

Amitriptyline is used in ankylosing spondylitis for pain relief and in some European countries it is officially approved as a preventive (prophylaxis) for patients with frequent/chronic migraines, usually 25 to 75 mg.

Unapproved/off-label/investigational use

Amitriptyline may be prescribed for other conditions such as insomnia, PTSD[3], migraine, rebound headache, chronic pain, chronic cough, postherpetic neuralgia (persistent pain following a shingles attack), carpal tunnel syndrome, fibromyalgia, vulvodynia, interstitial cystitis, male chronic pelvic pain syndrome, irritable bowel syndrome, diabetic peripheral neuropathy, neurological pain, and painful paresthesias related to multiple sclerosis and at low doses as a preventive (prophylaxis) for patients with frequent migraines.[4] Typically lower dosages are required for pain modification of 10 to 50 mg daily.[2]

Amitriptyline in low doses 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 that did not respond to a first-line treatment (famotidine or mosapride).[5]

Side effects

Common side effects of using amitriptyline are dry mouth, extreme weight gain, drowsiness, muscle stiffness, nausea, constipation, nervousness, dizziness, blurred vision and insomnia. Some rare side effects include tinnitus, hypotension, mania, psychosis, anticholinergic effects, heart block, arrhythmias, lip and mouth ulcers, 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.

Further information: Tricyclic antidepressant#Overdose

Footnotes

  1. Bendtsen L, Jensen R, Olesen J (September 1996). "A non-selective (amitriptyline), but not a selective (citalopram), serotonin reuptake inhibitor is effective in the prophylactic treatment of chronic tension-type headache". Journal of neurology, neurosurgery, and psychiatry 61 (3): 285–90. PMID 8795600. 
  2. 2.0 2.1 British National Formulary 45 (March 2003).
  3. National Institute for Clinical Excellence: The Treatment of PTSD in Adults and Children
  4. Ziegler D, Hurwitz A, Hassanein R, Kodanaz H, Preskorn S, Mason J (1987). "Migraine prophylaxis. A comparison of propranolol and amitriptyline". Arch Neurol 44 (5): 486–9. PMID 3579659. 
  5. Otaka M, Jin M, Odashima M, et al (June 2005). "New strategy of therapy for functional dyspepsia using famotidine, mosapride and amitriptyline". Aliment. Pharmacol. Ther. 21 (Suppl 2): 42–6. doi:10.1111/j.1365-2036.2005.02473.x. PMID 15943846. http://www.ingentaconnect.com/content/bsc/apt/2005/00000021/A00201s2/art00008. 

References