Sinequan (doxepin hydrochloride) is a tricyclic antidepressant (TCA) with a well-established profile for managing major depressive disorder and anxiety-related conditions. It functions primarily by inhibiting the reuptake of serotonin and norepinephrine, key neurotransmitters involved in mood regulation. This dual mechanism helps correct chemical imbalances in the brain, offering patients a path toward stabilized mood and reduced anxiety. Clinically trusted for decades, it is available in various formulations to suit individualized treatment plans under professional supervision.

Features

• Active ingredient: Doxepin hydrochloride
• Available in oral capsule and liquid concentrate forms
• Multiple strengths: 10 mg, 25 mg, 50 mg, 75 mg, 100 mg, 150 mg
• Extended half-life supporting once-daily dosing
• FDA-approved for depression and anxiety disorders
• Also indicated for pruritus associated with eczema

Benefits

• Effectively alleviates symptoms of major depressive disorder
• Reduces anxiety and associated somatic complaints
• Improves sleep architecture due to sedative properties at lower doses
• Long-acting formulation supports consistent therapeutic levels
• May reduce itching and inflammation in dermatological conditions
• Can be used adjunctively in chronic pain management

Common use

Sinequan is primarily prescribed for the treatment of major depressive disorder (MDD), characterized by persistent low mood, anhedonia, and cognitive disturbances. It is also indicated for anxiety disorders, including generalized anxiety disorder (GAD) and panic disorder. Off-label, it is sometimes used in the management of neuropathic pain, migraine prophylaxis, and treatment-resistant insomnia. Its antihistaminic properties make it useful for severe pruritus unresponsive to conventional therapies.

Dosage and direction

Dosage must be individualized based on severity of condition, patient response, and tolerability. For depression and anxiety in adults, the typical starting dose is 75 mg/day, administered orally, usually as a single daily dose at bedtime. This may be gradually increased to a therapeutic range of 75–150 mg/day; some patients may require up to 300 mg/day under close supervision. For elderly patients or those with hepatic impairment, lower initial doses (e.g., 10–25 mg/day) are recommended. The oral concentrate must be diluted with water, milk, or juice prior to administration. Dosage adjustments should occur at intervals of no less than several days to assess response and side effects.

Precautions

Patients should be monitored for worsening depression, suicidal ideation, or unusual changes in behavior, especially during initial treatment or dose adjustments. Sinequan may impair mental or physical abilities required for hazardous tasks such as driving. Use with caution in patients with a history of cardiovascular disease, glaucoma, urinary retention, or seizure disorders. Alcohol should be avoided due to additive CNS depression. Abrupt discontinuation may lead to withdrawal symptoms; taper gradually under medical supervision.

Contraindications

Sinequan is contraindicated in individuals with known hypersensitivity to doxepin or other tricyclic antidepressants. It should 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 with narrow-angle glaucoma, urinary retention, or during the acute recovery phase after myocardial infarction.

Possible side effects

Common side effects include drowsiness, dry mouth, blurred vision, constipation, and weight gain. Less frequently, patients may experience orthostatic hypotension, increased sweating, or tachycardia. Serious side effects, though rare, include seizures, arrhythmias, hepatotoxicity, agranulocytosis, and hyponatremia. Allergic reactions such as rash or photosensitivity may occur. Patients should report any persistent or severe adverse effects to their healthcare provider.

Drug interaction

Sinequan interacts with numerous medications. Concomitant use with SSRIs, SNRIs, triptans, or other serotonergic drugs increases risk of serotonin syndrome. It may potentiate effects of CNS depressants like alcohol, benzodiazepines, and opioids. Anticholinergic drugs may exacerbate side effects. Use with drugs that prolong QT interval (e.g., antipsychotics, antiarrhythmics) requires caution. Sinequan may reduce the efficacy of guanethidine and similar antihypertensives. CYP2D6 inhibitors may increase doxepin plasma levels.

Missed dose

If a dose is missed, it should be taken 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 regular dosing schedule. Do not double the dose to make up for a missed one. Consistent daily administration is important to maintain steady plasma concentrations.

Overdose

Overdose of Sinequan can be severe and potentially fatal. Symptoms may include severe drowsiness, confusion, agitation, hallucinations, tachycardia, hypotension, respiratory depression, seizures, and coma. Cardiac arrhythmias and conduction delays are particularly dangerous. Management involves immediate medical attention, gastric lavage if presented early, activated charcoal, and supportive care including ECG monitoring. There is no specific antidote.

Storage

Store at room temperature (20–25°C), away from light, moisture, and heat. Keep the bottle tightly closed and out of reach of children. Do not freeze the oral concentrate. Discard any unused medication after the expiration date or as directed, using proper disposal methods to prevent accidental ingestion or environmental contamination.

Disclaimer

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition or medication. Do not disregard professional medical advice or delay in seeking it because of something you have read here.

Reviews

Clinical studies and long-term use support the efficacy of Sinequan in treating depression and anxiety, with many patients reporting significant improvement in mood and functional capacity. Some users note sedation as a beneficial effect for sleep, while others find it limiting during daytime. Adherence to prescribed dosing and regular follow-up are frequently emphasized in positive outcomes. Individual responses vary, and a period of dose titration is often necessary to optimize benefits while minimizing side effects.