Antidepressants

Amitriptyline 25 mg, n50

International Nonproprietary Name (INN): Amitriptyline

Pharmaceutic group: Antidepressants

Presentation:

Tablets 10 mg n50 or 25 mg n50.

Available with prescription

Question?

THERE ARE CONTRAINDICATIONS. CAREFULLY READ THE INSTRUCTIONS FOR USE, OR OBTAIN A SPECIALIST ADVICE

Amitriptyline is a tricyclic antidepressant (TCA). It is the most widely used TCA and has at least equal efficacy against depression as the newer class of SSRIs according to a study from early 2001. As well as reducing depressive symptoms, these types of tricyclics also ease migraines, tension headaches, anxiety attacks and some schizophrenic symptoms.

Amitriptyline acts primarily as a serotonin-norepinephrine reuptake inhibitor, with strong actions on the serotonin transporter and moderate effects on the norepinephrine transporter. It has negligible influence on the dopamine transporter and therefore does not affect dopamine reuptake, being nearly 1,000 times weaker on it than on serotonin.

Amitriptyline additionally functions as a 5-HT2A, 5-HT2C, 5-HT6, 5-HT7, α1-adrenergic, H1, H2, H4, and mACh receptor antagonist, and σ1 receptor agonist. It has also been shown to be a relatively weak NMDA receptor negative allosteric modulator at the same binding site as phencyclidine. Amitriptyline inhibits sodium channels, L-type calcium channels, and Kv1.1, Kv7.2, and Kv7.3 voltage-gated potassium channels, and therefore acts as a sodium, calcium, and potassium channel blocker as well.

Recently, amitriptyline has been demonstrated to act as an agonist of the TrkA and TrkB receptors. It promotes the heterodimerization of these proteins in the absence of NGF and has potent neurotrophic activity both in-vivo and in-vitro in mouse models. These are the same receptors BDNF activate, an endogenous neurotrophin with powerful antidepressant effects, and as such this property may contribute significantly to its therapeutic efficacy against depression. Amitriptyline does also act as FIASMA (functional inhibitor of acid sphingomyelinase).

Amitriptyline is used for a number of medical conditions including: depressive disorders, anxiety disorders, attention deficit hyperactivity disorder, migraine prophylaxis, eating disorders, bipolar disorder, post-herpetic neuralgia, and insomnia.

Amitriptyline is used in ankylosing spondylitis for pain relief. It is also used as a preventive for patients with recurring biliary dyskinesia (sphincter of Oddi dysfunction).

Amitriptyline is also used in the treatment of nocturnal enuresis in children.

Amitriptyline may be prescribed for other conditions such as, post-traumatic stress disorder (PTSD), chronic pain, carpal tunnel syndrome (CTS), fibromyalgia, vulvodynia, interstitial cystitis, male chronic pelvic pain syndrome, irritable bowel syndrome (IBS), diabetic peripheral neuropathy, neurological pain, laryngeal sensory neuropathy, chronic fatigue syndrome and painful paresthesias related to multiple sclerosis. Typically lower dosages are required for pain modification of 10 to 50 mg daily.

USUAL ADULT DOSE FOR DEPRESSION.

Oral:

Initial dose: 25 to 100 mg per day in 3 to 4 divided doses or 50 to 100 mg at bedtime.

Maintenance dose: 25 to 150 mg per day in single or 3 to 4 divided doses. 25 mg per day at bedtime has been used for premenstrual depression. Dose increases should be made gradually. A small number of hospitalized patients may need as much as 300 mg per day.

Patients with major depressive disorder (MDD), both adult and pediatric, may experience worsening of their depression and/or the emergence of suicidal ideation and behavior (suicidality) or unusual changes in behavior, whether or not they are taking antidepressant medications, and this risk may persist until significant remission occurs. Suicide is a known risk of depression and certain other psychiatric disorders, and these disorders themselves are the strongest predictors of suicide. There has been a long-standing concern, however, that antidepressants may have a role in inducing worsening of depression and the emergence of suicidality in certain patients during the early phases of treatment. Pooled analyses of short-term placebo-controlled trials of antidepressant drugs (SSRIs and others) showed that these drugs increase the risk of suicidal thinking and behavior (suicidality) in children, adolescents, and young adults (ages 18-24) with major depressive disorder (MDD) and other psychiatric disorders. Short-term studies did not show an increase in the risk of suicidality with antidepressants compared to placebo in adults beyond age 24; there was a reduction with antidepressants compared to placebo in adults aged 65 and older.