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Brand Name: Asendin

Amoxapine, Asendin, is a tricyclic antidepressant used to treat depression. Relieves symptoms of depression. Usage, dosage, side effects.

Contents:

Description
Pharmacology
Indications and Usage
Contraindications
Warnings
Precautions
Drug Interactions
Adverse Reactions
Overdose
Dosage
Supplied

Description

Amoxapine (Asendin) is a tricyclic antidepressant used to treat depression.

Pharmacology

The mechanism of clinical action of amoxapine in man is not well understood. Amoxapine is not a monoamine oxidase (MAO) inhibitor. In animals, amoxapine inhibits the re-uptake of norepinephrine and, to a lesser degree, of serotonin, at adrenergic nerve endings and blocks the response of dopamine receptors to dopamine.

Amoxapine (Asendin) is absorbed rapidly and reaches peak blood levels approximately 90 minutes after ingestion.

Indications and Usage

Relieves the symptoms of depression.

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Contraindications

The use of amoxapine or other tricyclic antidepressants concurrently with a monoamine oxidase (MAO) inhibitor is contraindicated. Hyperpyretic crises, severe convulsions, and fatalities have occurred when similar tricyclic antidepressants were used in such combinations. It is advisable to have discontinued the MAO inhibitor for at least two weeks before treatment with amoxapine is started.

Patients hypersensitive to amoxapine should not be given the drug.

Cross-sensitivity between amoxapine and other dibenzazepines is a possibility.

Amoxapine is contraindicated during the acute recovery period after myocardial infarction.


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Warnings

Tardive Dyskinesia: Tardive dyskinesia is known to occur in patients treated with neuroleptics with antipsychotic properties and other drugs with substantial neuroleptic activity. It has also been observed with amoxapine administration. Although the dyskinetic syndrome may remit partially or completely if the medication is withdrawn, it is irreversible in some patients. At the present time there is uncertainty as to whether neuroleptic drugs differ in their potential to cause tardive dyskinesia.

Since there is a significant prevalence of this syndrome associated with the use of neuroleptic drugs, and since there is no known effective treatment, chronic use of these drugs should generally be restricted to patients for whom neuroleptics are known to be effective and for whom there is no alternative therapy available with better risk acceptability. If manifestations of tardive dyskinesia are detected during the use of amoxapine, the drug should be discontinued. The risk of a patient developing tardive dyskinesia and of the syndrome becoming irreversible appear to increase with the duration of treatment and the total amount of drugs administered, although, in some instances, tardive dyskinesia may develop after relatively short periods of treatment at low doses. The risk of developing tardive dyskinesia may, therefore, be minimized by reducing the dose of the neuroleptic drug used and its duration of administration, consistent with the effective management of the patient's condition. Continued use of neuroleptics should be periodically reassessed.

Cardiovascular: Patients with cardiovascular disease should be given amoxapine only under close supervision because of the tendency of the drug to produce sinus tachycardia and to prolong the conduction time. Myocardial infarction, arrhythmia, and strokes have occurred. The antihypertensive action of guanethidine and similar agents may be blocked. Because of its anticholinergic activity, use amoxapine with great caution in patients with glaucoma or a history of urinary retention. Patients with a history of seizures should be followed closely when amoxapine is administered because this drug is known to lower the convulsive threshold. Great care is required if amoxapine is administered to hyperthyroid patients or those receiving thyroid medication, because cardiac arrhythmias may develop.

Interference with Cognitive or Motor Performance: Amoxapine may impair the mental and/or physical abilities required for the performance of hazardous tasks, such as operating machinery or driving a car; therefore, the patient should be warned accordingly.

Excessive consumption of alcohol in combination with amoxapine therapy may have a potentiating effect, which may lead to the danger of increased suicidal attempts or overdosage, especially in patients with histories of emotional disturbances or suicidal ideation.

Usage in Pregnancy

Safe use of amoxapine during pregnancy and lactation has not been established; therefore, when the drug is administered to pregnant patients, nursing mothers, or women of childbearing potential, the potential benefits must be weighed against the possible hazards. Animal reproduction studies have yielded inconclusive results.

Usage in Children:: This drug is not recommended for use in children, since safety and effectiveness in the pediatric age group have not been established.

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Precautions

The use of amoxapine in schizophrenic patients may result in an exacerbation of the psychosis or may activate latent schizophrenic symptoms. If the drug is given to overactive or agitated patients, increased anxiety and agitation may occur. In manic depressive patients, amoxapine may cause symptoms of the manic phase to emerge.

Amoxapine may cause increased sensitivity to the sun. Avoid exposure to the sun, sunlamps, or tanning booths until you know how you react to this medicine. Use a sunscreen or protective clothing if you must be outside for a prolonged period.

Troublesome patient hostility may be aroused by the use of amoxapine. Epileptiform seizures may accompany its administration, as may happen with other drugs of its class.

Close supervision and careful adjustment of the dosage are required when amoxapine is used with other anticholinergic drugs and sympathomimetic drugs.

When possible, the drug should be discontinued several days before elective surgery.

The possibility of a suicidal attempt by a depressed patient remains after the initiation of treatment; in this regard, it is important that the least possible quantity of drug be dispensed at any given time.

Both elevation and lowering of blood sugar levels have been reported.

Caution should be exercised if amoxapine is administered together with cimetidine since cimetidine inhibits tricyclic antidepressant metabolism, and clinically significant increases in plasma levels of amoxapine may occur.

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Drug Interactions

Administration of reserpine during therapy with a tricyclic antidepressant has been shown to produce a "stimulating" effect in some depressed patients.

Close supervision and careful adjustment of the dosage are required when amoxapine is used with other anticholinergic drugs and sympathomimetic drugs.

Concurrent administration of cimetidine and tricyclic antidepressants can produce clinically significant increases in the plasma concentrations of the tricyclic antidepressant. The patient should be informed that the response to alcohol may be exaggerated.

Amoxapine may enhance the response to alcohol and the effects of barbiturates and other CNS depressants. Delirium has been reported with concurrent administration of amoxapine and disulfiram.

BEFORE USING THIS MEDICINE: INFORM YOUR DOCTOR OR PHARMACIST of all prescription and over-the-counter medicine that you are taking. This includes carbamazepine, cimetidine, dicumarol, clonidine, mibefradil, paroxetine, tramadol, other medicines for depression or emotional disorders, and medicines for seizures. Inform your doctor of any other medical conditions including heart conditions, allergies, pregnancy, or breast-feeding.

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Adverse Reactions

Stop taking this medicine and get emergency help immediately if any of the following side effects occur: Convulsions (seizures); difficult or fast breathing; fever with increased sweating; high or low (irregular) blood pressure; loss of bladder control; muscle stiffness (severe); lip smacking or puckering; uncontrolled chewing movements; or uncontrolled movements of hands, arms, or legs; pale skin; unusual severe tiredness or weakness.

NOTE:: Some of the adverse reactions noted below have not been specifically reported with amoxapine use. However, due to the close pharmacological similarities among the tricyclics, the reactions should be considered when prescribing amoxapine. Within each category the following adverse reactions are listed in order of decreasing severity.

Cardiovascular: Hypotension, hypertension, tachycardia, palpitation, myocardial infarction, arrhythmias, heart block, stroke.

Psychiatric: Confusional states (especially in the elderly) with hallucinations, disorientation, delusions; anxiety, restlessness, agitation; insomnia, panic, nightmares; hypomania; exacerbation of psychosis.

Neurologic: Numbness, tingling, paresthesias of extremities; incoordination, ataxia, tremors; peripheral neuropathy; extrapyramidal symptoms; seizures, alteration in EEG patterns; tinnitus.

Anticholinergic: Dry mouth and, rarely, associated sublingual adenitis; blurred vision, disturbance of accommodation, mydriasis; constipation, paralytic ileus; urinary retention, delayed micturition, dilation of the urinary tract.

Allergic: Skin rash, petechiae, urticaria, itching, photosensitization (avoid excessive exposure to sunlight); edema (general or of face and tongue), drug fever, cross-sensitivity with other tricyclic drugs.

Hematologic: Bone marrow depression, including agranulocytosis; eosinophilia; purpura; thrombocytopenia.

Gastrointestinal: Nausea and vomiting, anorexia, epigastric distress, diarrhea, peculiar taste, stomatitis, abdominal cramps, blacktongue.

Endocrine: Gynecomastia in the male, breast enlargement and galactorrhea in the female; increased or decreased libido, impotence; testicular swelling; elevation or depression of blood sugar levels; syndrome of inappropriate ADH (antidiuretic hormone) secretion.

Other: Jaundice (simulating obstructive), altered liver function; weight gain or loss; perspiration; flushing; urinary frequency, nocturia; drowsiness, dizziness, weakness, fatigue; headache; parotid swelling; alopecia.

Withdrawal Symptoms: Though these are not indicative of addiction, abrupt cessation of treatment after prolonged therapy may produce nausea, headache, and malaise.

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Overdose

Symptoms: Toxic overdosage may result in confusion, restlessness, agitation, vomiting, hyperpyrexia, muscle rigidity, hyperactive reflexes, tachycardia, ECG evidence of impaired conduction, shock, congestive heart failure, stupor, coma, and CNS stimulation with convulsions (seizures) followed by respiratory depression. Deaths have occurred following overdosage with drugs of this class.

Treatment

If you or someone you know may have used more than the recommended dose of this medicine, contact your local poison control center or emergency room immediately.

Treatment should be symptomatic and supportive, but with special attention to prevention or control of seizures. Renal failure may develop a few days after substantial amoxapine overdosage in patients who may appear otherwise recovered. Therefore, patients who may have ingested an overdosage of amoxapine, particularly children, should be hospitalized and kept under close surveillance.

Empty stomach contents and administer activated charcoal.

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Dosage

After you start using this medicine, the initial clinical effect usually occurs within 2 weeks of administration, but may be seen in some patients within 4 to 7 days. If your symptoms do not improve after taking this medicine for 4 weeks, inform your doctor.

Do not exceed the recommended dosage or take this medicine for longer than prescribed. Do not stop taking this medicine without checking with your doctor.

  • Follow the directions for using this medicine provided by your doctor.
  • Store this medicine at room temperature, away from heat and light.
  • Continue to take this medicine even if you feel better. Do not miss any doses.
  • If you miss a dose of this medicine, take it as soon as possible. If it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not take 2 doses at once. If you take 1 dose daily at bedtime, do not take missed dose the next morning.

Additional Information:: Do not share this medicine with others for whom it was not prescribed. Do not use this medicine for other health conditions. Keep this medicine out of the reach of children.

IF USING THIS MEDICINE FOR AN EXTENDED PERIOD OF TIME, obtain refills before your supply runs out.

Amoxapine is not recommended for children.

The dosage must be individualized according to the requirements of each patient. Treatment should be initiated at the lowest recommended dose and increased gradually with careful assessment of clinical response and any evidence of intolerance. Once effective dosage is well established, the total daily dosage may be given in a single daily dose (not to exceed 300 mg) at bedtime. Total daily dosages higher than 300 mg should be given in divided doses. Care should be taken not to increase the dosage of amoxapine if manifestations of extrapyramidal effects occur, as there is a possibility of development of tardive dyskinesia with this drug.

Usual Adult Dose: At first, 50 milligrams (mg) two to three times a day. Your doctor may increase your dose gradually as needed. In severely depressed hospitalized patients or patients under close supervision, a higher initial dose of 50 mg 3 times daily may be indicated, and this may be increased to 100 mg 2 or 3 times daily. The usual optimum dose is 150 to 300 mg daily, but some patients may require higher doses, up to 400 mg or more daily, depending on tolerance and response of each individual patient. Some hospitalized patients have received doses up to 600 mg daily in divided doses. When higher doses are used, it is essential to exclude history of convulsive disorders.

Elderly Patients: At first, 25 mg two to three times a day. Your doctor may increase your dose gradually as needed.

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How Supplied

Tablets:: Scored tablets come in dosages of 25 mg, 50 mg, 100 mg.

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Detailed Info on Signs, Symptoms, Causes, Treatments of Depression


The information in this monograph is not intended to cover all possible uses, directions, precautions, drug interactions or adverse effects. This information is generalized and is not intended as specific medical advice. If you have questions about the medicines you are taking or would like more information, check with your doctor, pharmacist, or nurse. Last updated 3/03.

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