Amitriptyline

Today's med: Amitriptyline (a mee TRIP ti leen)

(brand names: Elavil, Sentravil PM-25, Vanatrip; Index term: Amitriptyline Hydrochloride)

Drug Class: Tricyclic Antidepressant (Tertiary amine)

Action: Increases the synaptic concentration of serotonin and/or norepinephrine in the central nervous system by inhibition of their reuptake by the presynaptic neuronal membrane

Other Drugs in this class: Nortriptyline,Imipramine, Clomipramine, Doxepin,Trimipramine, 

Desipramine, Amitriptyline hydrochloride, Amoxapine, Protriptyline,Chlordiazepoxide/Amitriptyline,Clomipramine hydrochloride,Perphenazine/Amitriptyline, Imipramine hydrochloride, Nortriptyline Hydrochloride,Doxepin hydrochloride, Imipramine Pamoate, Trimipramine Maleate,Desipramine hydrochloride, Protriptyline hydrochloride

Indications: Relief of symptoms of depression

Use: Unlabeled

Analgesic for certain chronic and neuropathic pain (including diabetic neuropathy); prophylaxis against migraine headaches; treatment of depressive disorders in children; post-traumatic stress disorder (PTSD)

Contraindications: Hypersensitivity to amitriptyline or any component of the formulation (cross-sensitivity with other tricyclics may occur); use of MAO inhibitors within past 14 days; acute recovery phase following myocardial infarction; concurrent use of cisapride.

Adverse Effects: Anticholinergic effects may be pronounced; moderate to marked sedation can occur (tolerance to these effects usually occurs).

Most common S/E: Dry mouth, drowsiness, dizziness, taste problems, weight gain, increased hunger, HA

Infrequent S/E: Parkinson Sx, blurred vision, arrhythmia, orthostatic hypotension, erectile dysfunction, hallucination, dysuria, urinary retention, confusion, anxiety, sexual dysfunction, constipation, insomnia, hyperhydrosis, vomiting, nausea, anorexia, diarrhea, tinnitus

Rare S/E: Serotonin Syndrome, MI, Heart block, ECG changes, stroke, eosinophilia, bone marrow depression, suicidal thoughts, HTN, tachycardia, urticaria, alopecia, seizures, rash, excess ADH secretion, pruritis, black tongue, photosensitivity, swelling of testes, breast enlargement, xerostomia

Warnings:  Suicidal thinking/behavior: [U.S. Boxed Warning]: Antidepressants increase the risk of suicidal thinking and behavior in children, adolescents, and young adults (18-24 years of age) with major depressive disorder (MDD) and other psychiatric disorders; consider risk prior to prescribing. Short-term studies did not show an increased risk in patients >24 years of age and showed a decreased risk in patients ≥65 years. Closely monitor patients for clinical worsening, suicidality, or unusual changes in behavior, particularly during the initial 1-2 months of therapy or during periods of dosage adjustments (increases or decreases); the patient’s family or caregiver should be instructed to closely observe the patient and communicate condition with healthcare provider. A medication guide concerning the use of antidepressants should be dispensed with each prescription.Amitriptyline is not FDA-approved for use in children <12 years of age.

• Elderly: Avoid use in this age group due to its potent anticholinergic and sedative properties, and potential to cause orthostatic hypotension. In addition, may cause or exacerbate syndrome of inappropriate antidiuretic hormone secretion or hyponatremia; monitor sodium closely with initiation or dosage adjustments in older adults (Beers Criteria).

Pregnancy Risk Factor C: Teratogenic effects have been observed in animal studies. Amitriptyline crosses the human placenta; CNS effects, limb deformities and developmental delay have been noted in case reports.

Standard Dosing: (Tablet, as hydrochloride: 10 mg, 25 mg, 50 mg, 75 mg, 100 mg, 150 mg)

Children:

Chronic pain management (unlabeled use): Oral: Initial: 0.1 mg/kg at bedtime, may advance as tolerated over 2-3 weeks to 0.5-2 mg/kg at bedtime

Depressive disorders (unlabeled use): Oral: Initial doses of 1 mg/kg/day given in 3 divided doses with increases to 1.5 mg/kg/day have been reported in a small number of children (n=9) 9-12 years of age; clinically, doses up to 3 mg/kg/day (5 mg/kg/day if monitored closely) have been proposed

Migraine prophylaxis (unlabeled use): Oral: Initial: 0.25 mg/kg/day, given at bedtime; increase dose by 0.25 mg/kg/day to maximum 1 mg/kg/day. Reported dosing ranges: 0.1-2 mg/kg/day; maximum suggested dose: 10 mg.

Adolescents: Depressive disorders: Oral: Initial: 25-50 mg/day; may administer in divided doses; increase gradually to 100 mg/day in divided doses

Adults:

Depression: Oral: 50-150 mg/day single dose at bedtime or in divided doses; dose may be gradually increased up to 300 mg/day

Chronic pain management (unlabeled use): Oral: Initial: 25 mg at bedtime; may increase as tolerated to 100 mg/day

Diabetic neuropathy (unlabeled use): Oral: 25-100 mg/day (Bril, 2011)

Migraine prophylaxis (unlabeled use): Oral: Initial: 10-25 mg at bedtime; usual dose: 150 mg; reported dosing ranges: 10-400 mg/day

Post-traumatic stress disorder (PTSD) (unlabeled use): Oral: 75-200 mg/day

Elderly: Depression: Oral: Initial: 10-25 mg at bedtime; dose should be increased in 10-25 mg increments every week if tolerated; dose range: 25-150 mg/day

Drug interactions: Link: http://www.drugs.com/drug-interactions/amitriptyline.html

A total of 1015 drugs (5703 brand and generic names) are known to interact with amitriptyline.

• 256 major drug interactions (1765 brand and generic names)
• 699 moderate drug interactions (3462 brand and generic names)
• 60 minor drug interactions (476 brand and generic names)

Show all medications in the database that may interact with amitriptyline.

Use of this medication with alcohol can increase risk of side effects.

CYP2D6 Inhibitors: May decrease the metabolism of CYP2D6 Substrates

St Johns Wort: May increase the metabolism of Tricyclic Antidepressants. The risk of serotonin syndrome may theoretically be increased. Consider therapy modification

Amitriptyline OD: dry, hot, red, can't see or pee...

Also, found this gem...

With an overdose or misuse of medications with significant anticholinergic effect, the patient can be:

Blind as a bat (blurred vision)

Dry as a bone (dry mouth)

Red as a beet (flushing)

Mad as a hatter (confusion)

Hot as a hare (hyperthermia)

Can’t see(vision changes)

Can’t pee(urinary retention)

Can’t (do something that rhymes with “spit,” constipation)

Note that a milder form of these findings can be present in an elderly patient who has taken an over-the-counter sleep aid containing diphenhydramine (Benadryl), a first-generation antihistamine, or any medication know to have significant anticholinergic effect.

(Source: http://www.medicalmnemonics.com/, original attribution unknown)