Brand Name: Adapin, Sinequan
Generic Name: Doxepin

Adapin, Sinequan, Doxepin is a tricyclic antidepressant used to relieve mental depression, depression that sometimes occurs with anxiety. Detailed info on uses, dosage and side-effects of Adapin below.

Contents:

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

Description

Doxepin hydrochloride is one of a class of psychotherapeutic agents known as dibenzoxepin tricyclic compounds. Tricyclic antidepressants are used to relieve mental depression and depression that sometimes occurs with anxiety.

Pharmacology

The mechanism of action of doxepin HCl is not definitely known. It is not a central nervous system stimulant nor a monoamine oxidase inhibitor. The current hypothesis is that the clinical effects are due, at least in part, to influences on the adrenergic activity at the synapses so that deactivation of norepinephrine by reuptake into the nerve terminals is prevented.

Doxepin HCl is virtually devoid of euphoria as a side effect. Characteristic of this type of compound, doxepin HCl has not been demonstrated to produce the physical tolerance or psychological dependence associated with addictive compounds.

Indications and Usage

The drug is recommended for:

• Psychoneurotic patients with depression and/or anxiety.
• Depression and/or anxiety associated with alcoholism (not to be taken concomitantly with alcohol).
• Depression and/or anxiety associated with organic disease (the possibility of drug interaction should be considered if the patient is receiving other drugs concomitantly).
• Psychotic depressive disorders with associated anxiety including involutional depression and manic-depressive disorders.

The target symptoms of psychoneurosis that respond particularly well to doxepin include anxiety, tension, depression, somatic symptoms and concerns, sleep disturbances, guilt, lack of energy, fear, apprehension and worry.

Contraindications

Doxepin is contraindicated in individuals who have shown hypersensitivity to the drug or to other dibenzoxepin compounds.

Doxepin is contraindicated in patients with glaucoma or a tendency to urinary retention. These disorders should be ruled out, particularly in older patients.

Owing to lack of clinical experience in the pediatric population, doxepin is not recommended for use in children under 12 years of age.

Tricyclic agents are generally contraindicated during the acute recovery phase following myocardial infarction and in the presence of acute congestive heart failure, as well as in patients with a history of blood dyscrasias and severe liver disease.

Warnings

Tricyclic antidepressant drugs, particularly when given in high doses, can induce sinus tachycardia, changes in conduction time and arrhythmias. There have been reports of unexpected death in patients with heart disease. Heart attacks and strokes have also been reported in people using Tricyclics.

Close supervision is required when doxepin is given to hyperthyroid patients or those receiving thyroid medication because of the possibility of cardiovascular toxicity. At doses above 150 mg/day, it may block the antihypertensive effect of guanethidine and related compounds.

Usage in Pregnancy

Since there is no experience in pregnant women who have received this drug, safety in pregnancy has not been established. There has been a report of apnea and drowsiness occurring in a nursing infant whose mother was taking doxepin.

Precautions

Since drowsiness may occur with the use of this drug, patients should be warned of the possibility and cautioned against driving a car or operating dangerous machinery while taking the drug. Patients should also be cautioned that their response to alcohol may be potentiated.

Since suicide is an inherent risk in any depressed patient and may remain so until significant improvement has occurred, patients should be closely supervised during the early course of therapy. Prescriptions should be written for the smallest feasible amount. This type of patient should not have easy access to large quantities of doxepin.

Should increased symptoms of psychosis or shift to manic symptomatology occur, it may be necessary to reduce dosage or add a major tranquilizer to the dosage regimen.

Tricyclic antidepressants may also give rise to paralytic ileus, particularly in the elderly and in hospitalized patients. Therefore, appropriate measures should be taken if constipation occurs.

Do not have surgery or dental or emergency treatment unless you tell the doctor or dentist in charge that you are taking this medicine.

Doxepin should be used with caution in patients with impaired liver function or with a history of hepatic damage or blood dyscrasias. Periodic blood counts and liver function tests should be performed when patients receive doxepin in large doses or over prolonged periods.

Drug Interactions

Cimetidine: Cimetidine has been reported to produce clinically significant fluctuations in steady-state serum concentrations of various tricyclic antidepressants. Serious anticholinergic symptoms (i.e., severe dry mouth, urinary retention and blurred vision) have been associated with elevations in the serum levels of tricyclic antidepressant when cimetidine therapy is initiated. Additionally, higher than expected tricyclic antidepressant levels have been observed when they are begun in patients already taking cimetidine. In patients who have been reported to be well controlled on tricyclic antidepressants receiving concurrent cimetidine therapy, discontinuation of cimetidine has been reported to decrease established steady-state serum tricyclic antidepressant levels and compromise their therapeutic effects.

Alcohol: It should be kept in mind that alcohol ingestion may increase the danger inherent in any intentional or unintentional doxepin HCl overdosage. This is especially important in patients who may use alcohol excessively.

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.

Adverse Reactions

NOTE: Some of the adverse reactions noted below have not been specifically reported with doxepin use. However, due to the close pharmacological similarities among the tricyclics, the reactions should be considered when prescribing doxepin.

Anticholinergic Effects: Dry mouth, blurred vision, constipation, and urinary retention have been reported. If they do not subside with continued therapy, or become severe, it may be necessary to reduce the dosage.

Central Nervous System Effects: Drowsiness is the most commonly noticed side effect. This tends to disappear as therapy is continued. Other infrequently reported CNS side effects are confusion, disorientation, hallucinations, numbness, paresthesias, ataxia, extrapyramidal symptoms, seizures, tardive dyskinesia, and tremor.

Cardiovascular: Cardiovascular effects including hypotension, hypertension, and tachycardia have been reported occasionally.

Allergic: Skin rash, edema, photosensitization, and pruritus have occasionally occurred.

Hematologic: Eosinophilia has been reported in a few patients. There have been occasional reports of bone marrow depression manifesting as agranulocytosis, leukopenia, thrombocytopenia, and purpura.

Gastrointestinal: Nausea, vomiting, indigestion, taste disturbances, diarrhea, anorexia, and aphthous stomatitis have been reported.

Endocrine: Raised or lowered libido, testicular swelling, gynecomastia in males, enlargement of breasts and galactorrhea in the female, raising or lowering of blood sugar levels, and syndrome of inappropriate antidiuretic hormone secretion have been reported with tricyclic administration.

Other: Dizziness, tinnitus, weight gain, sweating, chills, fatigue, weakness, flushing, jaundice, alopecia, headache, exacerbation of asthma, and hyperpyrexia (in association with chlorpromazine) have been occasionally observed as adverse effects.

Withdrawal Symptoms: Abrupt cessation of treatment with tricyclic antidepressants after prolonged administration may produce nausea, headache and malaise. These symptoms are not indicative of addiction.

Overdose

Signs and Symptoms

Mild: Drowsiness, stupor, blurred vision, excessive dryness of mouth.

Severe: Respiratory depression, hypotension, coma, convulsions, cardiac arrhythmias and tachycardias.

Also: urinary retention (bladder atony), decreased gastrointestinal motility (paralytic ileus), hyperthermia (or hypothermia), hypertension, dilated pupils, hyperactive reflexes.

Treatment

Mild: Observation and supportive therapy is all that is usually necessary.

Severe: Medical management of severe doxepin overdosage consists of aggressive supportive therapy. Arrhythmias should be treated with the appropriate antiarrhythmic agent. It has been reported that many of the cardiovascular and CNS symptoms of tricyclic antidepressant poisoning in adults may be reversed by the slow intravenous administration of 1 mg to 3 mg of physostigmine salicylate. Because physostigmine is rapidly metabolized, the dosage should be repeated as required. Convulsions may respond to standard anticonvulsant therapy, however, barbiturates may potentiate any respiratory depression. Dialysis and forced diuresis generally are not of value in the management of overdosage due to high tissue and protein binding of doxepin.

If the patient is conscious, gastric lavage, with appropriate precautions to prevent pulmonary aspiration, should be performed even though doxepin is rapidly absorbed. The use of activated charcoal has been recommended, as has been continuous gastric lavage with saline for 24 hours or more. An adequate airway should be established in comatose patients and assisted ventilation used if necessary. EKG monitoring may be required for several days, since relapse after apparent recovery has been reported.

Deaths by deliberate or accidental overdosage have occurred with this class of drugs. Since the propensity for suicide is high in depressed patients, a suicide attempt by other means may occur during the recovery phase. The possibility of simultaneous ingestion of other drugs should also be considered.

Dosage

HOW TO USE THIS MEDICINE:

After you start using this medicine, several weeks may pass before you feel the full benefit.

• 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: If your symptoms do not improve after taking this medicine for 4 weeks, inform your doctor. 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.

For most patients with illness of mild to moderate severity, a starting daily dose of 75 mg is recommended. Dosage may subsequently be increased or decreased at appropriate intervals and according to individual response. The usual optimum dose range is 75 mg/day to 150 mg/day.

In more severely ill patients higher doses may be required with subsequent gradual increase to 300 mg/day if necessary. Additional therapeutic effect is rarely to be obtained by exceeding a dose of 300 mg/day.

In patients with very mild symptomatology or emotional symptoms accompanying organic disease, lower doses may suffice. Some of these patients have been controlled on doses as low as 25-50 mg/day. The total daily dosage of doxepin HCl may be given on a divided or once-a-day dosage schedule. If the once-a-day schedule is employed the maximum recommended dose is 150 mg/day. This dose may be given at bedtime. The 150 mg capsule strength is intended for maintenance therapy only and is not recommended for initiation of treatment.

Antianxiety effect is apparent before the antidepressant effect. Optimal antidepressant effect may not be evident for two to three weeks.

How Supplied

Each capsule contains: Doxepin HCl equivalent to 10, 25, 50, 75, 100 and 150 mg of doxepin.

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.

top . send to friend . medications homepage

Reviewed: 01/2006