Sinequan (doxepin hydrochloride) is a tricyclic antidepressant (TCA) with a well-established profile for managing major depressive disorder and anxiety-related conditions. As a potent agent with both antidepressant and anxiolytic properties, it works by modulating neurotransmitters in the brain, specifically by inhibiting the reuptake of serotonin and norepinephrine. Its therapeutic efficacy, backed by decades of clinical use, makes it a trusted option for physicians seeking to alleviate profound depressive symptoms and improve overall patient functioning. This comprehensive guide details its features, benefits, and essential safety information for informed usage.

Features

• Active ingredient: Doxepin hydrochloride
• Available in oral capsule formulations (e.g., 10 mg, 25 mg, 50 mg, 75 mg, 100 mg, 150 mg)
• Also available as an oral concentrate for flexible dosing
• Class: Tricyclic antidepressant (TCA)
• Mechanism: Serotonin and norepinephrine reuptake inhibition
• Half-life: Approximately 15–30 hours
• Bioavailability: High with oral administration

Benefits

• Effectively reduces symptoms of major depression, including low mood, anhedonia, and fatigue.
• Alleviates anxiety and associated somatic symptoms, promoting calmer daily functioning.
• Can improve sleep quality due to its sedative properties, particularly when administered at bedtime.
• Helps restore emotional stability and enhances overall quality of life with consistent use.
• Supported by extensive clinical history and real-world evidence of efficacy and tolerability.
• Offers dosing flexibility with multiple strengths and formulation options.

Common use

Sinequan is primarily indicated for the treatment of major depressive disorder (MDD) in adults. It is also used off-label for the management of anxiety disorders, including generalized anxiety disorder (GAD), and for certain sleep disorders due to its sedative effects. In some cases, it may be prescribed for neuropathic pain or pruritus (itching), leveraging its antihistaminic and neuromodulatory properties. Always use under strict medical supervision and only for conditions diagnosed by a healthcare professional.

Dosage and direction

Dosage must be individualized based on patient response, severity of symptoms, and tolerability. The usual starting dose for depression is 75 mg/day, administered orally, typically in divided doses or as a single daily dose at bedtime. Dosage may be gradually increased to a therapeutic range of 75–150 mg/day; some patients may require up to 300 mg/day under close monitoring. For elderly or debilitated patients, lower initial doses (e.g., 25–50 mg/day) are recommended. The oral concentrate should be diluted with water, milk, or juice prior to administration. Do not abruptly discontinue; taper gradually under medical guidance.

Precautions

Use with caution in patients with a history of cardiovascular disease, glaucoma, urinary retention, or seizure disorders. Monitor for emergence of anxiety, agitation, panic attacks, insomnia, irritability, or unusual changes in behavior, especially early in treatment or after dosage changes. Sinequan may impair mental or physical abilities required for driving or operating machinery. Avoid alcohol and other CNS depressants during therapy. Regular follow-up and clinical evaluation are advised to assess therapeutic progress and side effects.

Contraindications

Sinequan is contraindicated in individuals with known hypersensitivity to doxepin or other tricyclic antidepressants. It must not be used concomitantly with monoamine oxidase inhibitors (MAOIs) or within 14 days of discontinuing MAOI therapy due to risk of serotonin syndrome. Contraindicated in patients during the acute recovery phase after myocardial infarction and those with untreated narrow-angle glaucoma or severe urinary retention.

Possible side effect

Common side effects may include drowsiness, dizziness, dry mouth, blurred vision, constipation, and weight gain. Less frequently, orthostatic hypotension, increased sweating, and tachycardia may occur. Some patients may experience sexual dysfunction, confusion, or nightmares. Rare but serious adverse effects include leukopenia, agranulocytosis, and hepatotoxicity. Seek immediate medical attention if symptoms such as chest pain, seizures, difficulty urinating, or signs of allergic reaction (e.g., rash, swelling) develop.

Drug interaction

Sinequan may interact with MAOIs, leading to hypertensive crisis or serotonin syndrome. Concomitant use with other CNS depressants (e.g., benzodiazepines, opioids) can enhance sedative effects. It may potentiate the effects of anticholinergic drugs. Use with caution alongside drugs that prolong QT interval. Sinequan can increase serum levels of certain medications metabolized by CYP2D6. Always inform your healthcare provider of all prescription, over-the-counter, and herbal products you are taking.

Missed dose

If a dose is missed, take it as soon as remembered unless it is close to the time of the next scheduled dose. In that case, skip the missed dose and resume the usual dosing schedule. Do not double the dose to make up for a missed one. Consistent daily administration is important for maintaining stable plasma levels and therapeutic effect.

Overdose

Overdose of Sinequan can be severe and potentially fatal. Symptoms may include severe drowsiness, blurred vision, dry mouth, dilated pupils, confusion, hallucinations, hypotension, respiratory depression, seizures, cardiac arrhythmias, and coma. In case of suspected overdose, seek emergency medical attention immediately. Treatment is supportive and may include gastric lavage, activated charcoal, and monitoring of cardiac and respiratory function.

Storage

Store at room temperature (20–25°C or 68–77°F), in a tightly closed container, away from light, moisture, and heat. Keep out of reach of children and pets. Do not use after the expiration date printed on the packaging. Properly discard any unused or expired medication as advised by a pharmacist or local guidelines.

Disclaimer

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before starting, changing, or discontinuing any medication or treatment plan. Do not ignore or delay seeking professional medical advice based on information read here.

Reviews

Clinical studies and patient reports generally reflect Sinequan’s efficacy in alleviating symptoms of depression and anxiety, with many users noting improved mood and sleep over time. Some reviews highlight the initial sedative effect as beneficial for insomnia, while others mention side effects like dry mouth or drowsiness. Individual experiences vary; always discuss personal treatment responses with a prescribing physician.