Sinequan Side Effects Center

Last updated on RxList: 4/19/2021
Sinequan Side Effects Center

What Is Sinequan?

Sinequan (doxepin) is a tricyclic antidepressant used to treat symptoms of depression and/or anxiety associated with alcoholism, psychiatric conditions, or manic-depressive conditions. The brand name Sinequan is discontinued in the U.S. Generic forms are available.

What Are Side Effects of Sinequan?

Common side effects of Sinequan include:

  • drowsiness,
  • dizziness,
  • tiredness,
  • dry mouth,
  • blurred vision,
  • ringing in your ears,
  • nausea,
  • vomiting,
  • constipation,
  • weight gain,
  • increased sweating,
  • breast swelling (in men or women),
  • decreased sex drive, or
  • trouble urinating.

Suicidal thinking and behavior may occur in children, adolescents, and young adults taking Sinequan. Tell your doctor immediately if you have suicidal thoughts while taking Sinequan.

Dosage for Sinequan

For most patients with illness of mild to moderate severity, a starting daily dose of 75 mg doxepin is recommended. The usual optimum dose range is 75 mg/day to 150 mg/day.

What Drugs, Substances, or Supplements Interact with Sinequan?

Doxepin may interact with SSRI antidepressants, cimetidine, or heart rhythm medications. Tell your doctor all medications you use.

Sinequan During Pregnancy or Breastfeeding

During pregnancy, doxepin should be used only when prescribed. Since untreated depression can be a serious condition, do not stop using this medication unless directed by your doctor. This medication passes into breast milk and may have undesirable effects on a nursing infant. Breastfeeding while using this drug is not recommended.

Additional Information

Our Sinequan (doxepin) Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.


Learn to Spot Depression: Symptoms, Warning Signs, Medication See Slideshow
Sinequan Consumer Information

Get emergency medical help if you have signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Report any new or worsening symptoms to your doctor, such as: mood or behavior changes, anxiety, panic attacks, trouble sleeping, or if you feel impulsive, irritable, agitated, hostile, aggressive, restless, hyperactive (mentally or physically), more depressed, or have thoughts about suicide or hurting yourself.

Call your doctor at once if you have:

  • blurred vision, tunnel vision, eye pain or swelling, seeing halos around lights;
  • a light-headed feeling, like you might pass out;
  • tremors, restless muscle movements in your eyes, tongue, jaw, or neck;
  • severe constipation;
  • confusion, hallucinations, unusual thoughts, seizure (convulsions); or
  • painful or difficult urination.

Common side effects may include:

  • drowsiness, dizziness;
  • increased blood pressure;
  • vision changes;
  • rash, swelling;
  • nausea, vomiting, indigestion;
  • little or no urination;
  • dry mouth, constipation; or
  • decreased or increased sex drive.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Read the entire detailed patient monograph for Sinequan (Doxepin)


Depression is a(n) __________ . See Answer
Sinequan Professional Information


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

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


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


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


Nausea, vomiting, indigestion, taste disturbances, diarrhea, anorexia, and aphthous stomatitis have been reported. (See Anticholinergic Effects.)


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.


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

Withdrawal Symptoms

The possibility of development of withdrawal symptoms upon abrupt cessation of treatment after prolonged SINEQUAN administration should be borne in mind. These are not indicative of addiction and gradual withdrawal of medication should not cause these symptoms.

Read the entire FDA prescribing information for Sinequan (Doxepin)

© Sinequan Patient Information is supplied by Cerner Multum, Inc. and Sinequan Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.

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