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Amitriptyline (Elavil)
Amitriptyline in Brief
- Active ingredient: Amitriptyline hydrochloride
- Common brand names: Elavil, Amitrol
- Drug class: Tricyclic antidepressant (Tertiary amine)
- FDA Approved: May 1983
- Chemical Formula: C20H23N
- Pregnancy Category: C (Teratogenic effects have been observed in animal studies)
- Habit forming? No
- Originally discovered: 1950s, Merck Sharp and Dohme
History
The first tricyclic antidepressant discovered was imipramine, which
was discovered accidentally in a search for a new antipsychotic in the late 1950s.
The therapeutic and commercial success of N-aminoalkylphenothiazines
such as promethazine, promazine, and chlorpromazine, initiated an enormous
effort in the molecular modification of the polycyclic phenothiazine
ring structure and its N-aminoalkyl side chain.
Hafliger and Schinder, in 1951 US Patent 2,554,736, replaced the sulfur
bridge of the phenothiazine ring of promethazine with an ethylene bridge
to synthesize imipramine, a weak antihistaminic and mild anticholinergic
with sedative properties in normal human volunteers. Kuhn, a clinical
psychiatrist in Swiss psychiatric hospital, discovered that of some
500 patients with various psychiatric disorders that were treated, only
those with endogenous depression with mental and motor retardation showed
a remarkable improvement after about 1 to 6 weeks of daily imipramine
therapy.
Thus, the first clinically useful tricyclic antidepressant was discovered.
It did not take long for the diamine structure of an additional N-CH2
group in imipramine to be substituted with a C=CH group in amitriptyline.
Amitriptyline was another tricyclic antidepressant which soon became
widely used clinically 4.
FDA approved indications
- depression, endogenous depression is more likely to be alleviated than are other depressive states
Off-label & Investigational uses
- chronic pain management 7, 9, 10
- post-herpetic neuralgia 17, 18, 19
- diabetic peripheral neuropathy 15, 16
- fibromyalgia 21, 22
- migraine headaches prophylaxis 25, 26, 27
- childhood headaches 28
- chronic tension headache 3, 5, 29, 30
- drug-induced headache 6
- irritable bowel syndrome (IBS) 14, 38
- depressed phase of bipolar affective disorder
- somatoform pain disorder 32
- post traumatic stress disorder 33
- panic/anxiety disorders
- insomnia 34
- vulvodynia 35
- interstitial cystitis 36, 37
Analgesia
Clinical trials demonstrate that amitriptyline achieves at least a good
or moderate response in up to 65% of patients with post-herpetic neuralgia
and 75% of patients with painful diabetic neuropathy, neurogenic pain
syndromes that are often unresponsive to narcotic analgesics. Amitriptyline
has also demonstrated efficacy in patients with chronic non-malignant
pain 7, 9, 10.
In the study a dose of 20 mg/kg of amitriptyline reduced pain in the
second phase of the formalin test (an animal model of long-lasting pain
in humans). Since the analgesic effect was produced by a single dose,
which is insufficient to produce an antidepressant effect, these results
indicate that amitriptyline has analgesic properties that are independent
of its antidepressant properties 8.
Diabetic neuropathy
Amitriptyline reduces the pain caused by peripheral-nerve disease 16. Blockade
of norepinephrine reuptake is likely to mediate the analgesic effect
of amitriptyline in diabetic neuropathy.
Postherpetic neuralgia
Controlled clinical trials and extensive clinical experience have shown
that amitriptyline reduces the severity of post-herpetic neuralgia.
It is a reasonable first choice for PHN.
Amitriptyline is useful in treating postherpetic neuralgia and may not
act as an antidepressant. It may provide significant pain relief with
the dose 75 mg 18. The alleviant effect of amitriptyline in postherpetic
neuralgia appears not to be primarily linked with its serotoninergic effects
and is also independent of its effects on depression 19.
Fibromyalgia
Amitriptyline therapy can provide improvements in general health, pain,
sleep quality and quantity, and fatigue in the treatment of fibromyalgia
22. Clinical study demonstrated that amitriptyline 25 mg at night
is an effective therapeutic regimen for patients with fibromyalgia and
is associated with significant improvement in pain, sleep difficulties,
and fatigue on awakening.
Migraine prophylaxis The antimigraine
effect of amitriptyline is relatively independent of its antidepressant activity 25.
Amitriptyline can significantly reduce the severity, frequency, and duration of
headache attacks 27.
Childhood headaches
Amitriptyline is effective for the prophylaxis of
frequent headaches in children. A standardized dosing regimen (1 mg/kg per day)
can provide an overall perception of being better, and significantly
reduce severity and duration of headaches with minimal side effects.
The children are able to tolerate this dosing scheme and demonstrate
good adherence to a dosing schedule of once a day 28.
Interstitial cystitis
Amitriptyline (with maximum dosage 100 mg) appears to be safe
and effective for treating interstitial cystitis. Amitriptyline can
improve pain, urgency intensity, frequency and functional bladder capacity
37.
Amitriptyline "pros" and "cons"
Advantages:
- potent antidepressant
- well researched
- the only documented and most widely used prophylactic therapy for
chronic tension-type headache 31
- small efficacy advantage over other tricyclic antidepressants
- proven analgesic effects 8
- relatively early onset of antidepressive effect 12
Disadvantages:
- risk of fatality in overdose
- narrow therapeutic index
- strong anticholingergic properties, and as a result severe anticholingergic side effects
- sedation and mental or motor impairment
- can lower the seizure threshold
- cardiotoxicity
- weight gain (greater increase in weight than with nortriptyline,
desipramine, zimelidine, and imipramine) 39, 24
- possible decreased amount of REM sleep 23
Mechanism of action
Amitriptyline hydrochloride is an antidepressant with sedative effects.
Amitriptyline inhibits the reuptake of noradrenaline at the noradrenergic
nerve endings and the reuptake of serotonin (5-hydroxy tryptamine) at
the serotoninergic nerve endings in the central nervous system. These
two effects are considered to be the likely base of the antidepressant
effect. Amitriptyline also has a strong anticholinergic
effect 20.
Amitriptyline has ability to antagonize histamine H1 receptors and
appears to be a potent antihistamine 11.
Time for Amitriptyline to clear out the system
Elimination half-life varies from 24 to 46 hours. The
mean elimination half-life is about 36 hours 2.
Within 24 hours, approximately 25 to 50% of a dose of amitriptyline
is excreted in the urine as inactive metabolites; small amounts are excreted in the bile.
Onset of action
- Antidepressant effect: 4-6 weeks, it is recommended to reduce dosage
to lowest effective level. However, antidepressive effect may be noticed
as early as after 1 week of therapy 12.
- Migraine prophylaxis: 6 weeks, higher dosage may be required in
heavy smokers because of increased metabolism.
Further reading
References
- 1. U.S. FDA. Amitriptyline Prescribing Information.
- 2. Ziegler VE, Biggs JT, Ardekani AB, Rosen SH. Contribution to
the pharmacokinetics of amitriptyline. J Clin Pharmacol. 1978 Oct;18(10):462-7.
PubMed
- 3. Ashina S, Bendtsen L, Jensen R. Analgesic effect of amitriptyline
in chronic tension-type headache is not directly related to serotonin
reuptake inhibition. Pain. 2004 Mar;108(1-2):108-14. PubMed
- 4. Edward F. Domino, MD. History of Modern Psychopharmacology:
A Personal View With an Emphasis on Antidepressants. Psychosomatic Medicine 61:591-598 (1999)
Available at: http://www.psychosomaticmedicine.org/content/61/5/591.full
- 5.Go bel H, Hamouz V, Hansen C, Heininger K, Hirsch S, Lindner V,
Heuss D, Soyka D. Amitriptyline in therapy of chronic tension headache.
Nervenarzt. 1994 Oct;65(10):670-9. PubMed
- 6. Descombes S, Brefel-Courbon C, Thalamas C, Albucher JF, Rascol
O, Montastruc JL, Senard JM. Amitriptyline treatment in chronic drug-induced
headache: a double-blind comparative pilot study. Headache. 2001 Feb;41(2):178-82.
PubMed
- 7. Brenne E, van der Hagen K, Maehlum E, Husebo S. Treatment chronic
pain with amitriptyline. A double-blind dosage study with determination
of serum levels. Tidsskr Nor Laegeforen. 1997 Oct 10;117(24):3491-4.
PubMed
- 8. Acton J, McKenna JE, Melzack R. Amitriptyline produces analgesia
in the formalin pain test. Exp Neurol. 1992 Jul;117(1):94-6. PubMed
- 9. McQuay HJ, Carroll D, Glynn CJ. Dose-response for analgesic effect
of amitriptyline in chronic pain. Anaesthesia. 1993 Apr;48(4):281-5.
PubMed
- 10. Bryson HM, Wilde MI. Amitriptyline. A review of its pharmacological
properties and therapeutic use. 1996 Jun;8(6):459-76. PubMed
- 11. Richelson E. Tricyclic antidepressants and histamine H1 receptors.
Mayo Clin Proc. 1979 Oct;54(10):669-74.
- 12. Bech P. Meta-analysis of placebo-controlled trials with mirtazapine
using the core items of the Hamilton Depression Scale as evidence
of a pure antidepressive effect in the short-term treatment of major
depression. Int J Neuropsychopharmacol. 2001 Dec;4(4):337-45. PubMed
- 14. Morgan V, Pickens D, Gautam S, Kessler R, Mertz H. Amitriptyline
reduces rectal pain related activation of the anterior cingulate cortex
in patients with irritable bowel syndrome. Gut. 2005 May;54(5):601-7.
PubMed
- 15. Max MB, Culnane M, Schafer SC, Gracely RH, Walther DJ, Smoller
B, Dubner R. Amitriptyline relieves diabetic neuropathy pain in patients with normal or depressed mood.
Neurology. 1987 Apr;37(4):589-96.
- 16. Vrethem M, Boivie J, Arnqvist H, Holmgren H, Lindström T, Thorell LH. Amitriptyline and maprotiline
in the treatment of painful polyneuropathy in diabetics and nondiabetics. Clin J Pain. 1997 Dec;13(4):313-23.
PubMed
- 17. Max MB, Schafer SC, Culnane M, Smoller B, Dubner R, Gracely
RH. Amitriptyline, but not lorazepam, relieves postherpetic neuralgia.
Neurology. 1988 Sep;38(9):1427-32. PubMed
- 18. Watson CP, Evans RJ, Reed K, Merskey H, Goldsmith L, Warsh J.
Amitriptyline in postherpetic neuralgia. Neurology. 1982 Jun;32(6):671-3.
- 19. Watson CP, Evans RJ. A comparative trial of amitriptyline and
zimelidine in post-herpetic neuralgia. Pain. 1985 Dec;23(4):387-94.
PubMed
- 20. Hyttel J, Christensen AV, Fjalland B. Neuropharmacological properties
of amitriptyline, nortriptyline and their metabolites. Acta Pharmacol
Toxicol (Copenh). 1980 Jul;47(1):53-7. PubMed
- 21. Jaeschke R, Adachi J, Guyatt G, Keller J, Wong B. Clinical usefulness
of amitriptyline in fibromyalgia: the results of 23 N-of-1 randomized
controlled trials. J Rheumatol. 1991 Mar;18(3):447-51. PubMed
- 22. Hannonen P, Malminiemi K, Yli-Kerttula U, Isomeri R, Roponen
P. A randomized, double-blind, placebo-controlled study of moclobemide
and amitriptyline in the treatment of fibromyalgia in females without
psychiatric disorder. Br J Rheumatol. 1998 Dec;37(12):1279-86.
- 23. Riemann D, Velthaus S, Laubenthal S, Müller WE, Berger M. REM-suppressing effects of amitriptyline and amitriptyline-N-oxide: results of two uncontrolled pilot trials. Pharmacopsychiatry. 1990 Nov;23(6):253-8.
- 24. Berken GH, Weinstein DO, Stern WC. Weight gain. A side-effect
of tricyclic antidepressants. J Affect Disord. 1984 Oct;7(2):133-8.
PubMed
- 25. Couch JR, Hassanein RS. Amitriptyline in migraine prophylaxis.
Arch Neurol. 1979 Nov;36(11):695-9. PubMed
- 26. Couch JR, Ziegler DK, Hassanein R. Amitriptyline in the prophylaxis
of migraine. Neurology. 1976 Feb;26(2):121-7.
- 27. Ziegler DK, Hurwitz A, Preskorn S, Hassanein R, Seim J. Propranolol
and amitriptyline in prophylaxis of migraine. Arch Neurol. 1993 Aug;50(8):825-30.
- 28. Hershey AD, Powers SW, Bentti AL, Degrauw TJ. Effectiveness
of amitriptyline in the prophylactic management of childhood headaches.
Headache. 2000 Jul-Aug;40(7):539-49. PubMed
- 29. Boline PD, Kassak K, Bronfort G, Nelson C, Anderson AV. Spinal
manipulation vs. amitriptyline for the treatment of chronic tension-type
headaches: a randomized clinical trial. J Manipulative Physiol Ther.
1995 Mar-Apr;18(3):148-54. PubMed
- 30. Cerbo R, Barbanti P, Fabbrini G, Pascali MP, Catarci T. Amitriptyline
is effective in chronic but not in episodic tension-type headache:
pathogenetic implications. Headache. 1998 Jun;38(6):453-7. PubMed
- 31. Ashina S, Bendtsen L, Jensen R. Analgesic effect of amitriptyline
in chronic tension-type headache is not directly related to serotonin
reuptake inhibition. Pain. 2004 Mar;108(1-2):108-14. PubMed
- 32. Ikawa M, Yamada K, Ikeuchi S. Efficacy of amitriptyline for
treatment of somatoform pain disorder in the orofacial region: A case
series. J Orofac Pain. 2006 Summer;20(3):234-40. PubMed
- 33. Davidson J, Kudler H, Smith R, Mahorney SL, Lipper S, Hammett
E, Saunders WB, Cavenar JO. Treatment of posttraumatic stress disorder
with amitriptyline and placebo. Arch Gen Psychiatry. 1990 Mar;47(3):259-66.
- 34. Srisurapanont M, Jarusuraisin N. Amitriptyline vs. lorazepam
in the treatment of opiate-withdrawal insomnia: a randomized double-blind
study. Acta Psychiatr Scand. 1998 Mar;97(3):233-5.
- 35. Reed BD, Caron AM, Gorenflo DW, Haefner HK. Treatment of vulvodynia
with tricyclic antidepressants: efficacy and associated factors. J
Low Genit Tract Dis. 2006 Oct;10(4):245-51. PubMed
- 36. van Ophoven A, Hertle L. Long-term results of amitriptyline
treatment for interstitial cystitis. J Urol. 2005 Nov;174(5):1837-40.
PubMed
- 37. van Ophoven A, Pokupic S, Heinecke A, Hertle L. A prospective,
randomized, placebo controlled, double-blind study of amitriptyline
for the treatment of interstitial cystitis. J Urol. 2004 Aug;172(2):533-6.
PubMed
- 38. Rajagopalan M, Kurian G, John J. Symptom relief with amitriptyline
in the irritable bowel syndrome. J Gastroenterol Hepatol. 1998 Jul;13(7):738-41.
PubMed
- 39. Fernstrom MH, Kupfer DJ. Antidepressant-induced weight gain. Psychiatry Res.
PubMed
Published: August 26, 2008
Last updated: January 16, 2012
Interesting facts
- Nortriptyline (marketed under brand name Pamelor) is an intermediate
active metabolite of amitriptyline.
- Amitriptyline is the only documented
and most widely used antidepressant for tension headache prophylaxis.
- The first tricyclic antidepressant discovered was imipramine,
which was discovered accidentally in a search for a new antipsychotic
medicine in the late 1950s.
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