Quitaxon

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Quitaxon

Medically reviewed

Laura Arias

Last updated on 22/12/2025

This page provides general, reference-level information compiled from official medical sources. It is not a substitute for professional medical advice, diagnosis, or treatment. For decisions about your health, please consult a qualified healthcare professional.

Overview of Quitaxon

Property Description
Active ingredient Doxepin hydrochloride
Forms Oral capsule, Oral concentrate, Topical cream
Pharmacological class Tricyclic Antidepressant (TCA)
General purpose Mood stabilization and distress alleviation
Origin Synthetic (Dibenzoxepin derivative)

What Type of Medicine is Quitaxon (Doxepin)?

Quitaxon is the brand name for a synthetic prescription-only psychotropic agent whose active compound is Doxepin. The medication is classified as a Tricyclic Antidepressant (TCA). This compound is a tertiary amine derivative, which structurally differentiates it from newer, more selective antidepressant agents. Quitaxon is presented as a single active ingredient product with broad application versatility, reflected in its dosage forms: the common oral capsule and oral concentrate for systemic delivery, and a topical cream.

Composition and General Action of Doxepin

The medication contains the active substance Doxepin hydrochloride, which is administered as an isomeric mixture of its E- and Z-stereoisomers. Quitaxon’s general action involves a dual mechanism: it supports chemical balance by regulating key neurotransmitters like norepinephrine and serotonin in the brain. The drug is characterized by its affinity for the histamine H1 receptor, which provides its calming and sedative properties—a differentiating factor that informs its general purpose. This combined effect allows Quitaxon to serve the general purpose of helping to stabilize mood and alleviate distress by modulating the nervous system.

What side effects are possible with Quitaxon?

Possible Side Effects and Safety Information

The safety profile for Quitaxon (Doxepin) is based on official regulatory documentation and reflects the drug’s classification as a tricyclic antidepressant (TCA). Adverse reactions are categorized by frequency, which is derived from clinical data found in government-approved labeling.

Frequency and System-Organ Effects

The most frequently documented adverse effects relate to the drug's action on the central and autonomic nervous systems.

Classification Common Examples
Very Common Drowsiness/Somnolence, Dry Mouth
Common Constipation, Dizziness, Blurred Vision, Tachycardia

Side effects are often grouped by the body system affected, including Nervous System Disorders (tremor, confusion) and Gastrointestinal Disorders (nausea, vomiting), as categorized in regulatory documents.

Serious Adverse Reactions and Safety Constraints

The prescribing information contains specific warnings for reactions that are clinically significant but may occur less frequently:

  • Suicidal Thoughts and Behaviors: Risk is heightened during the initial few months of therapy and at times of dosage changes, particularly in younger adults.
  • Cardiac Risks: Serious events, including QT interval prolongation and other cardiac arrhythmias, are documented safety concerns.
  • Glaucoma and Urinary Retention: Due to its anticholinergic properties, Quitaxon is contraindicated in patients with untreated narrow-angle glaucoma or a history of severe urinary retention.

Older adults are noted to have increased sensitivity to certain effects, including oversedation and confusion. The drug is also contraindicated for use with or within 14 days of discontinuing a Monoamine Oxidase Inhibitor (MAOI). These regulatory domains ensure the safety profile is clearly communicated, distinguishing between expected, high-frequency effects and mandatory warnings.

Overdose and Emergency Response

Overdose and when to seek help

Overdose of Quitaxon (Doxepin), a tricyclic antidepressant, is classified by regulatory authorities as potentially life-threatening and requires immediate medical attention. The official prescribing information documents severe toxicity impacting the Central Nervous System (CNS) and the Cardiovascular System.


Documented Overdose Manifestations

System Severe Manifestations
Cardiovascular Cardiac arrhythmias (irregular heartbeat, potentially fatal), severe hypotension, and QRS prolongation on ECG.
CNS A spectrum from drowsiness, confusion, and stupor to seizures and coma.
Anticholinergic Urinary retention, dry mouth, blurred vision, and hyperthermia.

Required Emergency Actions

If overdose is suspected, official regulatory guidance mandates patients must seek immediate medical attention or get medical help right away. Management is primarily symptomatic and supportive. Continuous ECG monitoring is required for several days due to the risk of relapse or late-onset cardiac conduction abnormalities. Specific interventions, such as the use of intravenous sodium bicarbonate, are documented for managing cardiovascular toxicity. Due to high tissue binding, procedures like haemodialysis are generally reported as ineffective.

Therapeutic Uses of Quitaxon

Quick Facts: Uses of Quitaxon

  • Addresses symptoms associated with Major Depressive Disorder.
  • Aids in the management of Anxiety Disorders.
  • Helps relieve short-term difficulty in maintaining sleep (Insomnia).
  • Used for the temporary relief of itching (pruritus) associated with certain skin conditions.

Quitaxon (doxepin) is utilized in therapeutic approaches to manage several patient conditions. The medication is prescribed to address symptoms related to Major Depressive Disorder and for the supportive care of Anxiety Disorders. These uses focus on helping to stabilize mood and relieve feelings of tension and worry.

Furthermore, Quitaxon is employed for the short-term clinical management of insomnia, specifically for individuals experiencing difficulty with sleep maintenance. The oral form is intended to assist in achieving adequate rest periods.

A separate topical formulation of doxepin is approved for the temporary relief of moderate pruritus (itching) associated with certain conditions like atopic dermatitis or lichen simplex chronicus. The prescribing decision is always determined by a healthcare professional based on individual patient needs.

Regulatory References

  1. NIH MedlinePlus guidance

Eligibility and Restrictions for Use

Eligibility Map: Who Can and Cannot Use Quitaxon (Doxepin) — Official Regulatory Information

Quitaxon eligibility is strictly defined by regulatory documents, distinguishing between approved adult use, absolute contraindications, and populations requiring conditional use or for whom safety is not established.

Eligibility Scope Status Defined by Regulators
Populations for whom use is allowed Adults (18+ years) for approved indications. Older adults are eligible but require special caution and close monitoring.
Populations for whom use is contraindicated Individuals with a known hypersensitivity to the drug; patients with glaucoma or a tendency to urinary retention; and any patient currently taking or within 14 days of discontinuing a Monoamine Oxidase Inhibitor (MAOI).
Age-related eligibility rules Use in pediatric patients (typically under 12 or 18 years, depending on the indication) is generally not established or not recommended.
Condition-specific eligibility rules Use requires caution in patients with hepatic impairment (liver issues) or a history of seizures or cardiovascular disease.
Pregnancy and lactation eligibility Pregnancy safety has not been established; use in the third trimester may increase risks to the neonate. Breastfeeding is not recommended as the drug is excreted into human milk.

Connection to the overall eligibility profile: Official documents establish absolute exclusions for populations with specific conditions like severe urinary retention or concurrent MAOI use. Use is otherwise restricted based on life stage and metabolic health, defining the adult population as the one for whom use is primarily established. The regulatory classifications of "contraindicated," "not established," and "not recommended" govern the use of this medicine.

What should I know about interactions with other medicines?

Interactions with other medicines and products

The interaction profile for Quitaxon (Doxepin) is defined by pharmacokinetic and pharmacodynamic constraints documented in regulatory labeling.

Interaction Category Specific Regulatory Statement
Contraindicated Combinations The co-administration of Monoamine Oxidase Inhibitors (MAOIs), including Linezolid and intravenous Methylene Blue, is a formal contraindication. A 14-day separation period is mandatory after stopping an MAOI before starting Doxepin.
Exposure Modification Doxepin is primarily cleared by CYP2D6 and CYP2C19 enzymes. Co-administration with strong CYP2D6 inhibitors may significantly increase Doxepin’s plasma concentration (exposure). Cimetidine is also documented to cause a measurable increase in Doxepin systemic exposure.
Pharmacodynamic Additive Effects The sedative effects of Quitaxon may be potentiated by alcohol or other CNS Depressants, including sedating antihistamines. Concomitant use with other Serotonergic Drugs heightens the risk of Serotonin Syndrome. Doxepin may also block the antihypertensive effect of agents like Guanethidine at higher doses.
Timing & Population Notes Doxepin tablets for insomnia require a minimum 3-hour timing separation from a meal. The effects of Doxepin may be increased in patients with hepatic impairment due to slower removal of the medicine from the body.

This profile describes official, label-based restrictions concerning drug metabolism, additive physiological effects, and administration timing rules, which define the documented requirements for co-administering Doxepin with other substances.

Mechanism of Action

How Quitaxon Works

Quitaxon modulates central neurochemistry through a dual mechanism affecting monoamine systems and the histaminergic pathway. It acts as an inhibitor of the Norepinephrine Transporter ( NET) and the Serotonin Transporter ( SERT). This dual reuptake inhibition elevates the effective concentration of both neurotransmitters in the synaptic cleft, driving chronic adaptive changes within neurocircuitry and leading to a modulation of CNS signaling pathways.

Simultaneously, the drug exhibits a high binding affinity for the Histamine H1 receptor ( H1 R), where it functions as a potent antagonist. This action immediately inhibits central histaminergic activity, a primary pathway for arousal signaling. This mechanism is the basis for the inhibition of CNS arousal signaling, resulting in the modulation of the wakefulness cycle.

The drug's structural profile also confers antagonism at secondary targets, including Muscarinic Acetylcholine ( M) receptors and alpha1-Adrenergic receptors (alpha1 AR). These supplementary interactions affect various involuntary physiological systems regulated by the autonomic nervous system, shaping the resulting systemic physiological effects.

Dosage and Administration Information

Quitaxon (Doxepin) administration protocols are strictly defined by the specific formulation used and its corresponding route of administration: oral for systemic effects (capsule, solution, tablet) or topical for localized use (cream).

Oral systemic dosing for high-dose regimens typically begins at 25 mg three times daily or 75 mg once daily, with a total recommended daily dose range between 75 mg and 150 mg. The maximum labeled daily dose is 300 mg. The oral concentrate form must be accurately measured and diluted immediately with 120 mL of an approved liquid (such as water or certain fruit juices like orange or pineapple) and should not be mixed with carbonated beverages. When systemic treatment is concluded, the dosage should be gradually reduced until discontinued.

For the low-dose oral tablet, the standard adult regimen is 6 mg once daily, taken within 30 minutes of bedtime. This dose must not be taken within 3 hours of a meal to prevent potential next-day effects. Older adults (65 years and over) are advised to start at 3 mg. If a dose of the low-dose tablet is missed, it should be skipped, and the patient should resume the regular schedule the following night.

The topical cream is applied as a thin film four times daily, with an interval of at least three to four hours between applications. Use is restricted to short-term management and should not exceed eight days of chronic application. The area of skin treated must not be covered with an occlusive bandage or dressing to avoid increased absorption.

Recent Clinical Evidence

Research Evidence / Overview of Studies for Quitaxon (Doxepin)


Evidence for Use in Major Depressive Disorder and Associated Anxiety

The research base for Quitaxon's use in Major Depressive Disorder (MDD) and associated anxiety is derived largely from earlier trials. These studies were often conducted as Randomized Controlled Trials (RCTs), and researchers examined outcomes related to systemic or functional imbalance, such as scores on clinician-rated scales designed to measure symptom intensity or variability. Findings describe patterns observed in the studies where individuals receiving Quitaxon had measured changes in depressive symptoms and measures of anxiety compared to patients who received a placebo. A key limitation is that many of these are older trials, and long-term outcomes are not fully established based on this data alone.


Evidence for Use in Insomnia (Sleep Maintenance)

Research has explored Quitaxon for insomnia, specifically for difficulty with sleep maintenance, in multiple recent Randomized Controlled Trials (RCTs). These studies was evaluated in adults and older adults. The research examined outcomes related to Total Sleep Time, Sleep Efficiency, and measures of waking up after initially falling asleep (WASO). Studies report that the low-dose formulation was associated with measured differences in these core sleep measures compared to a placebo. Follow-up durations were limited in these pivotal trials, generally focusing only on the acute to intermediate period (up to three months).


Evidence for Topical Use for Itching (Pruritus)

The topical cream formulation of Quitaxon was studied for the temporary evaluation of physical discomfort (itching) in individuals with specific inflammatory or irritative states like eczema. Research has been conducted using Randomized, Double-Blind, Vehicle-Controlled Trials. The studies monitored symptom scores in the observed populations over very short defined time intervals, generally less than ten days. A major research limitation frame is that the follow-up durations were limited; because of this, the evidence provides limited insight into the potential for long-term or repeated use.


What is Still Uncertain About Quitaxon Research

The evidence highlights what is known — and what is still uncertain. Long-term outcomes for both sleep maintenance and antidepressant use are not fully established by controlled trials over periods longer than a year. There is a lack of adequate research for the safety and whether it can be used in the pediatric population (children under 12), and the results of many trials apply only to the populations studied and do not necessarily reflect outcomes for individuals with complex, numerous comorbidities.

Key Studies & References

  1. Comparative efficacy and safety of hypnotics for insomnia in older adults: a systematic review and network meta-analysis

Frequently Asked Questions (FAQ)

Common questions about Quitaxon (FAQ)

Q: What are the most common things people misunderstand about Quitaxon?

Misunderstandings often relate to the different forms and uses of the medication. Official information describes a higher-dose regimen prescribed for conditions like depression or anxiety, and a separate, very low-dose tablet that is used specifically for managing sleep maintenance issues. It is important not to confuse the distinct uses of these different dosage forms.


Q: How does Quitaxon compare generally to other medicines for the same condition?

Quitaxon is classified as a tricyclic antidepressant (TCA) that acts as an SNRI. While its action involves affecting key brain chemicals (like norepinephrine and serotonin), this specific pharmacological profile is a distinguishing characteristic among similar medicines.


Q: Does Quitaxon interact with common over-the-counter pain relievers?

Official drug interaction profiles list specific medications and substances that must be avoided, such as MAOIs and alcohol. Over-the-counter pain relievers are not listed as formal contraindications in the regulatory documents reviewed. However, official information indicates the importance of informing a healthcare provider of every medication being used.


Q: Are there any herbal supplements that have known interactions with Quitaxon?

Official drug information indicates the importance of informing a healthcare provider about all substances, including supplements, to avoid potential unknown interactions.


Q: What kind of foods or drinks might affect how Quitaxon works?

The administration protocols for the low-dose tablet for insomnia state that it must not be taken within three hours of a meal. Additionally, the oral concentrate form of the medicine must not be mixed with carbonated beverages.


Q: Is alcohol consumption completely forbidden while taking Quitaxon?

Official warnings state that co-administration with alcohol may significantly increase the sedative effects of the medicine. Due to the potential for compounded effects on the central nervous system, this combination is a documented safety concern due to the risk of compounded effects.


Q: If I miss a planned administration, what is the general recommendation?

For the systemic oral forms of the medicine, the general protocol is to take the missed dose as soon as it is remembered. However, if it is almost time for the next scheduled dose, the missed dose is typically skipped, and the regular schedule is resumed. Doubling the dose is not recommended.


Q: Is Quitaxon something you take for a long time or a short course?

The topical cream formulation is only indicated for short-term use (not to exceed eight days). For the systemic oral use in conditions like depression, maintenance trials have examined the continued use of therapy.


Q: What is the expected timeframe for full effectiveness of Quitaxon?

Official documentation indicates that the anti-anxiety effect is often apparent before the full antidepressant effect occurs. The optimal antidepressant effect may take two to three weeks to become fully evident.


Q: Can Quitaxon be used by children?

Official regulatory documents state that the safety and efficacy of the medicine have not been established in pediatric patients (children and adolescents). Therefore, use in the pediatric population is generally not recommended.


Q: Is Quitaxon considered appropriate for elderly people?

Dose selection for older adults should be approached with caution, typically starting at the low end of the dosing range. The elderly population may exhibit increased sensitivity to certain side effects, which is a factor in dose adjustment considerations.


Q: Does Quitaxon have restrictions for people with kidney or liver issues?

Caution is advised for patients with hepatic impairment (liver issues), as dosage reduction may be required due to slower removal of the medicine from the body. Caution is also advised for patients with renal impairment (kidney issues).


Q: What has the research evidence for Quitaxon focused on most recently?

Recent clinical evidence reviews have primarily focused on the low-dose formulation of doxepin and its effect on sleep maintenance. These studies examined objective and subjective measures of sleep in adults and older adults.


Q: What does 'clinical evidence' mean when discussing Quitaxon?

Clinical evidence refers to documented data derived from controlled research studies, such as randomized controlled trials. This information is used by regulatory bodies to evaluate the medicine's effects on symptoms or sleep parameters.


Q: Is it possible to become dependent on Quitaxon?

Official labeling states that the medication has not been demonstrated to produce the physical tolerance or psychological dependence associated with controlled, addictive compounds. Discontinuing the medication is typically managed by a gradual reduction in dosage.


Q: Does Quitaxon affect a person's ability to drive?

Yes. Due to the potential for effects such as sedation and drowsiness, official warnings caution patients against driving a car or operating dangerous machinery while taking the medicine.


Q: What should I do if I think Quitaxon is not working for me?

Official patient guidance recommends keeping all scheduled follow-up visits with the healthcare provider. Contacting the healthcare provider is the documented procedure for discussing concerns about symptoms or lack of therapeutic effect.


Q: What are some less common but serious side effects of Quitaxon that people should know about?

Official labeling contains specific warnings for serious adverse reactions, including the documented risk concerning suicidal thoughts and behaviors. Other clinically significant risks include cardiac issues (such as dysrhythmias) and the potential for Serotonin Syndrome.


Q: Does Quitaxon have a sedative effect?

Yes, official documents note that the medicine is classified as a CNS depressant. This sedative property is due to its strong effect on the histamine H1 receptor and is the basis for the very common side effect of drowsiness.


Q: How quickly do patients typically begin to notice the expected effects of Quitaxon?

For the systemic use, the anti-anxiety effect is generally noted before the full antidepressant effect occurs. The optimal antidepressant effect may take two to three weeks to develop fully.


Q: How is Quitaxon different from a traditional antidepressant/antipsychotic/etc. (general class comparison)?

Quitaxon is classified as a tricyclic antidepressant (TCA). It is distinguished by its unique pharmacological profile, which combines a serotonin and norepinephrine reuptake inhibition effect with a highly potent antagonistic effect on the histamine H1 receptor.


Q: What is the risk of having an allergic reaction to Quitaxon?

Hypersensitivity to the drug is a formal contraindication described in regulatory documents. Although rare, documented hypersensitivity reactions have included swelling of the tongue (edema) and hives (urticaria).


Q: What is the consensus on Quitaxon's effectiveness among medical bodies?

Regulatory bodies have established the efficacy of Quitaxon for its specific approved indications, such as Major Depressive Disorder, based on the review of evidence from controlled clinical trials.


Q: What happens if Quitaxon is taken past its expiration date?

For legal and safety reasons, manufacturers do not guarantee the full potency and safety of a medication past its official expiration date. Use past this date is not recommended, and disposal methods are governed by local pharmaceutical waste guidelines.


Q: Is Quitaxon considered a first-line treatment for [Condition A]?

Quitaxon is an approved drug with established efficacy for its indicated conditions. Official medical guidelines may recommend consideration of newer drug classes or therapies before initiating a TCA like Quitaxon, depending on the patient's individual profile.


Q: Can Quitaxon affect laboratory test results?

The medicine is extensively metabolized by CYP enzymes. Patient information indicates the importance of informing all healthcare providers and laboratory personnel of all medicines being taken.


Q: Is Quitaxon commonly confused with any other drug name?

Official patient safety bodies, such as the ISMP, monitor lists of drug names that are commonly confused (sound-alike/look-alike) to help prevent potential medication errors.


Q: Do side effects of Quitaxon usually improve over time?

Some side effects, such as drowsiness or dry mouth, may occur that often lessen as the body adjusts to the medicine. This is not guaranteed for everyone, and serious side effects documented in the labeling are a matter for clinical evaluation.


Q: Does Quitaxon cause dry mouth or increased thirst?

Yes, dry mouth is listed as a very common adverse effect in official documentation. Increased thirst is also a reported symptom documented in the official adverse reaction listings.


Q: Can Quitaxon be split or crushed, generally speaking?

The oral capsules are generally intended to be swallowed whole. The official prescribing information advises that the capsules should not be split or crushed, and an oral concentrate liquid form is available as an alternative.


Q: Is Quitaxon ever prescribed 'as needed'?

The medicine is taken on a scheduled, consistent basis to maintain a steady level in the body. The systemic forms are not generally prescribed on an 'as needed' basis, as adherence to a schedule is important for achieving the expected therapeutic effect.

How should Quitaxon be stored and disposed of?

The storage and disposal of Quitaxon (doxepin) must follow regulatory guidance to ensure product integrity and safety.


Official Storage Conditions

  • Doxepin Oral Solution Concentrate must be kept at Controlled Room Temperature (20 C to 25 C) in a tight, light-resistant container.
  • Quitaxon Film-coated Tablets require no special precautions for storage and have a labeled shelf life of 3 years.
  • All forms must be stored out of the sight and reach of children.

Disposal Instructions

Unused or expired medication should be disposed of in accordance with local requirements for pharmaceutical waste. The preferred method is using a drug take-back location or mail-back program, as recommended by the FDA. If not immediately available, the medicine can be mixed with an undesirable substance (e.g., dirt) in a sealed bag before disposal in household trash.

Attention! Always consult to a doctor or pharmacist before using pills or medicines.

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