Amitriptyline Adverse Reactions
- abdominal pain
- agitation
- akathisia
- anorexia
- anxiety
- blurred vision
- breast enlargement
- cardiomyopathy
- confusion
- constipation
- cycloplegia
- diarrhea
- dizziness
- drowsiness
- EEG changes
- ejaculation dysfunction
- erythema
- fever
- galactorrhea
- gynecomastia
- heart failure
- hostility
- hypertension
- ileus
- impotence
- insomnia
- irritability
- jaundice
- libido decrease
- mania
- mydriasis
- myocardial infarction
- nausea/vomiting
- neuroleptic malignant syndrome
- ocular hypertension
- orthostatic hypotension
- palpitations
- photosensitivity
- PR prolongation
- pruritus
- pseudoparkinsonism
- QT prolongation
- seizures
- serotonin syndrome
- SIADH
- stroke
- suicidal ideation
- testicular swelling
- torsade de pointes
- tremor
- urinary retention
- urticaria
- vasculitis
- ventricular tachycardia
- withdrawal
- xerostomia
Amitriptyline Adverse Reactions
The symptoms of aggressiveness, akathisia (psychomotor restlessness), agitation, anxiety, insomnia, irritability, hostility, mania, hypomania, impulsivity, and panic attacks have been reported in adult and pediatric patients being treated with antidepressants for major depressive disorder as well as for other indications, both psychiatric and nonpsychiatric. Although a causal link between the emergence of such symptoms and either the worsening of depression and/or the emergence of suicidal impulses has not been established, there is concern that such symptoms may represent precursors to emerging suicidality. Consideration should be given to changing the therapeutic regimen, including possibly discontinuing the medication, in patients whose depression is persistently worse, or who are experiencing emergent suicidality or symptoms that might be precursors to worsening depression, suicidal ideation or suicidality, especially if these symptoms are severe, abrupt in onset, or were not part of the patient’s presenting symptoms. Many of these adverse symptoms have been reported in clinical trials and have not always been associated with suicidality.
A wide variety of cardiovascular side effects can result from the use of tricyclic antidepressants due to their direct quinidine-like action, their potent anticholinergic properties, and their ability to potentiate norepinephrine. Ventricular tachycardia, palpitations, hypertension, and orthostatic hypotension all can be precipitated, with the possibility of more severe reactions occurring such as myocardial infarction, congestive heart failure, or stroke. Imipramine, and possibly other tricyclic antidepressants, can cause both PR prolongation and QT prolongation. Imipramine and nortriptyline are known to prolong the QRS interval. Other tricyclics would be expected to produce similar ECG changes. The cardiovascular response to tricyclic antidepressants depends on the specific agent and the dose. Although all tricyclic antidepressants are thought to be proarrhythmic after acute overdoses, at therapeutic doses, their actions on the conducting system of the heart may vary. Imipramine has been utilized therapeutically for its antiarrhythmic effect. The cardiovascular response to tricyclic antidepressants is varied, and patients most at risk have preexisting cardiovascular disease. While amitriptyline is included on lists of drugs associated with either QT prolongation or torsade de pointes, this reaction is rare at therapeutic doses. In very rare instances, cardiomyopathy associated with amitriptyline has also been reported in spontaneous, post-marketing reports.
Drowsiness is the most frequent adverse CNS effect during therapy with tricyclic antidepressants. Sedation can be made into a desirable effect by administration of the tricyclic antidepressant at bedtime, which minimizes undesirable drowsiness during the day. Dizziness is usually due to orthostatic hypotension and can be reduced by having the patient change positions more slowly. Some patients exhibit excitation. Confusion is most apparent in the elderly.
Peripheral nervous system adverse reactions can occur during therapy with tricyclic antidepressants. Tremor may result from norepinephrine reuptake blockade. Rarely, extrapyramidal symptoms can occur in both young and elderly patients. Pseudoparkinsonism is more likely to occur in the elderly, especially if they are receiving high doses.
Seizures and EEG changes have been observed more commonly in children than in adults during therapy with tricyclic antidepressants. Patients who have a preexisting seizure disorder may require increased concentrations of their anticonvulsant to maintain seizure control.
Ocular manifestations of the anticholinergic actions of tricyclic antidepressants can result in blurred vision due to cycloplegia, mydriasis, and increased intraocular pressure. Ocular hypertension can precipitate a crisis in patients with angle-closure glaucoma. Ophthalmological examination is recommended when there are visual changes.
Gastrointestinal manifestations of tricyclic antidepressants’ anticholinergic activity include dry mouth (xerostomia), constipation, urinary retention, adynamic ileus, abdominal pain or cramps, nausea/vomiting, anorexia, diarrhea, and jaundice. Constipation is more commonly observed in elderly patients. If these symptoms become severe, discontinuation of the drug may be required.
Allergic reactions to tricyclic antidepressants can include photosensitivity, vasculitis, erythema, urticaria, fever, and/or pruritus. Fever also may indicate a blood dyscrasia.
The effects of tricyclic antidepressants on the endocrine system can result in sexual dysfunction including libido decrease, impotence, testicular swelling, ejaculation dysfunction (no or painful ejaculation), breast enlargement, and galactorrhea in females or gynecomastia in males. The syndrome of inappropriate secretion of antidiuretic hormone (SIADH) has been reported. Glucose metabolism can be altered and should be monitored in patients with diabetes mellitus.
Patients receiving prolonged therapy with high doses of tricyclic antidepressants can experience withdrawal symptoms following abrupt discontinuation of the tricyclic antidepressant. Symptoms of cholinergic rebound such as nausea, vomiting, or diarrhea can occur. This particularly occurs with the tertiary amine tricyclic antidepressants: amitriptyline, imipramine, clomipramine, trimipramine, and doxepin.
A syndrome resembling neuroleptic malignant syndrome (NMS) has been very rarely reported after starting or increasing the dose of amitriptyline. Cases have occurred in patients receiving amitriptyline with or without concomitant medications known to cause NMS. Symptoms have included muscle rigidity, fever, mental status changes, diaphoresis, tachycardia and tremor.
Very rare cases of serotonin syndrome have been reported with amitriptyline when the drug is administered concomitantly with other medications known to cause serotonin syndrome, particularly with SSRIs. Amitriptyline is a fairly potent inhibitor of serotonin reuptake.
[ Last revised: 10/11/2005 10:06:00 AM ]
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