Saturday, August 27, 2011

Amitriptyline Side Effects



Amitriptyline Side Effects: Brand name Elavil. Amitriptylene is available in 10 mg, 25 mg, 50 mg, 75 mg, 100 mg and 150 mg oral tablets/capsules. Amitriptyline is one of the older classes of drugs available for treatment of depression called the tricyclic antidepressants, and this class of drugs is notorious for common and often intolerable side effects when used at the doses required to successfully treat depression. Antidepressant dosing is typically 50-150 mg daily, with a maximum daily dose of 300 mg. In these doses many patients are intolerably drowsy and have anticholenrgic side effects including constipation, dry mouth and fatigue. Amitriptylene is now more commonly used to treat chronic pain, especially neuropathic pain and as a sleep aid now than as an antidepressant. Often drugs like the SSRIs or SNRIs (see Citalopram side effects and Venlafaxine side effects) are much better tolerated for depression, but amitriptyline may be very effective at lower doses for the other pain indications.
Black Box Warnings: Amitriptyline may increase suicidality risk in children and young adults under age 25 as well as in patients with other psychiatric disorders. Amitriptyline is not approved for pediatric use. See the manufacturer’s prescriber guidelines for details of the black box warnings.
Common Amitriptyline Side Effects: As noted above very bothersome side effects often limit the use of amitriptyline. The most common of these is dry mouth. Although this often diminishes with time, it can be so annoying that patients just do not tolerate this drug. Other anticholinergic amitriptyline side effects include constipation, sweating, drowsiness, drowsiness, blurred vision, dizziness, and restlessness. Central nervous system depressant effects can include incoordination, weakness, disorientation, confusion, insomnia, anxiety or agitation, and tremor. Cardiac common side effects can include palpitations and tachycardia. Increased appetite and weight gain are often quite a big problems. Other GI amitriptyline side effects include nausea and vomiting and skin reactions including rash, photosensitivity, itching and hives are fairly common. Reduced sex drive is often noted, as is erectile dysfunction, urinary retention and urinary frequency. Gynecomastia and galactorrhea are also fairly common.
Serious Amitriptyline Side Effects: Unfortunately the list of amitriptyline side effects includes a lon list of potentially life threatening issues that are seen both with intentional and accidental overdose and sometimes at usual dose administration. These include ventricular arrhythmias, QT prolongation, torsades de pointes, atrioventricular block, hypertension, orthostatic hypotension, syncope, myocardial infarction, and stroke as cardiovascular amitriptyline side effects. Serious central nervous system amitriptyline side effects include ataxia, seizures, extrapyramidal symptoms and tardive dyskinesia Serious neuropsychiatric amitriptyline side serious side can include suicidality, mania and hypomania, hallucinations, and worsening of depression. Other serious issues can include paralytic ileus, increase in intraocular pressure, and a wide variety of hematologic amitriptyline side effects that including agranulocytosis, leukopenia and thrombocytopenia. Serious allergic reactions can occur too, including angioedema and SIADH, hepatitis, hyperthermia and heat stroke are also listed as serious amitriptyline side effects.
Cautions and Drug Interactions: The manufacturer’s list of cautions and drug interactions for amitriptyline is extensive, and readers should see the prescribing guidelines for complete information. Of particular note are cautions of suicidality in young patients, concerns in a variety of cardiac conditions where arrhythmias are common including the post MI state, in older men with prostate disease where urinary retention may be precipitated, in patients with seizure disorder where seizures may be precipitated, and in patients at risk for intentional or accidental over dosage. In glaucoma patients, especially with closed angle glaucoma, the intraocular pressure may be further increased. Amitriptyline is contraindicated for use with non-selective MAO inhibitors, class 1A antiarrhthmics, cisapride (no longer available in the US), dronedarone, primozide, triptorelin and flumazenil. Yohimbe is a more commonly used drug that is also contraindicated with amitriptyline. The list of drugs where use with amitriptyline is cautioned is extensive. Some notable drugs on this list include amiodarone, cimetidine, clarithromycin, epinephrine (includes inhaled epinephrine like Primatene, dobutamine, sotalol, and St. John’s wort. Monitoring may be indicated with carbamazepine, desmopressin, ephedra, olanzapine/fluoxetine, all SSRIs, and venlafaxine. Caution is advised with any potentially sedating side effects, additional anticholinergic side effects, or that require hepatic metabolism using the CYP450: 2D6, 3A4 or 1A2 pathways.
Unusual Amitriptyline Side Effects: The most unusual issue with amitriptyline is that the therapeutic window is so narrow. A therapeutic dose for depression may be up to 300 mg and the potentially lethal dose may be as low as 900-1200 mg. Special care is needed to keep the medication away from young children who might accidently ingest the medication, or others who might intentionally take the medication either in a suicide attempt or for recreational use.

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