Serzone

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Serzone

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Medically reviewed

Rosario Oropesa

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 Serzone

Quick Facts

Property Description
Active Ingredient Nefazodone
Form Tablet (Oral administration)
Pharmacological Class Serotonin Antagonist and Reuptake Inhibitor (SARI)
General Purpose Mood regulation and stabilization
Origin Synthetic Phenylpiperazine derivative

Serzone is a prescription medication whose active ingredient is Nefazodone, a compound synthetically created as a Phenylpiperazine derivative. The brand name Serzone was originally marketed by Bristol-Myers Squibb, though the generic form, containing Nefazodone hydrochloride, remains available today. It is administered via an oral tablet and functions as a single-ingredient product, which ensures a consistent delivery of the active substance.

Serzone's Classification: The Serotonin Antagonist and Reuptake Inhibitor (SARI) Class

Serzone is classified as a Second-Generation Antidepressant, belonging to the distinct Serotonin Antagonist and Reuptake Inhibitor (SARI) group. This pharmacological class reflects a multimodal spectrum of action that is clinically recognized for its differentiation from other antidepressant classes. The drug acts as a Serotonin Modulator, combining a weak influence on the reuptake of serotonin and norepinephrine with a potent and selective blockade of the 5-HT2A receptor. This dual profile of receptor antagonism coupled with reuptake inhibition is the core structural and functional feature defining the SARI classification, distinguishing it from simple reuptake inhibitors.

The General Purpose of Nefazodone

By modulating the activity of key neurotransmitters, the general purpose of Nefazodone is to assist in restoring chemical balance in the brain associated with mood regulation. Its unique dual mechanism is considered beneficial in managing emotional and mental states that require pharmacological support. This type of medication is typically utilized for adults requiring intervention to achieve stability in the face of mood dysregulation.

Regulatory References

  1. NIH

What side effects are possible with Serzone?

Possible Side Effects and Safety Information

The regulatory safety profile for Serzone (nefazodone) is defined by its officially documented adverse reactions, which include serious risks and common effects, grouped by system-organ classes.

Serious Adverse Reactions

The most significant and serious risk documented in regulatory labeling is life-threatening hepatic failure and severe liver injury. This risk necessitates that the medication not be initiated in patients with active liver disease or persistently elevated baseline liver enzymes. Furthermore, official documents note the risk of increased suicidal thinking and behavior in children, adolescents, and young adults (up to age 24), particularly in the first few months of treatment or following dose changes. Other documented serious reactions include Serotonin Syndrome and Priapism.

Common Adverse Reactions and Organ Systems

The most frequently reported adverse reactions are classified as common in official regulatory documents and often involve the Nervous System and Gastrointestinal System. These include somnolence (drowsiness), dizziness, nausea, dry mouth, constipation, and asthenia (weakness).

System-Organ Class Common Adverse Reactions
Nervous System Disorders Somnolence, Dizziness, Confusion
Gastrointestinal Disorders Dry Mouth, Nausea, Constipation
Special Senses Blurred Vision

Safety Restrictions and Populations

Official labeling contraindicates the use of Serzone with potent inhibitors of the CYP3A4 enzyme, as well as with Monoamine Oxidase Inhibitors (MAOIs), requiring a mandatory washout period. In terms of population-specific safety, the medication is not approved for pediatric patients. For older adults (over 65), a lower starting dose is recommended.

Overdose and Emergency Response

Overdose and when to seek help

Overdose Scope

Category Official Regulatory Statement
Documented Overdose Presentations: Nausea, vomiting, and somnolence (drowsiness) are documented clinical manifestations.
Physiological systems affected (as stated in label): Central Nervous System (CNS) effects, including convulsion (seizure), are documented.
Dose-related or exposure-related factors (if applicable): Fatalities have been reported, primarily in cases involving an overdose in combination with alcohol and/or other substances.
Population-specific overdose notes (if applicable): No specific population-based overdose considerations are explicitly documented in the acute overdose section of the primary regulatory label.
Emergency-response statements (as written in official documents): Seek immediate medical assistance. Treatment is generally symptomatic and supportive.
When immediate medical help is required (label-derived phrasing only): Immediate medical attention is required for known or suspected overdose, particularly if symptoms include a convulsion, loss of consciousness, or difficulty breathing.

Overdose Classifications (High-Level)

Category Official Regulatory Statement
Severity classification (as defined in official documents): Manifestations range from common symptoms (nausea, somnolence) to severe outcomes (convulsion, fatalities in poly-drug cases).
Regulatory basis (EMA / FDA / etc.): Information is based on official FDA prescribing documentation and supporting government health resources.
Overdose-context constraints (as defined in official documents): No specific antidote is known; management requires supportive care.

Resulting Overdose Structure

Official overdose statements:

  • The most commonly documented acute manifestations of nefazodone overdose are nausea, vomiting, and somnolence.
  • Severe outcomes reported in the regulatory documentation include convulsion (seizure) and, rarely, fatalities, particularly when the overdose involves alcohol and/or other substances.
  • Regulators mandate that patients seek immediate medical assistance for any known or suspected overdose.
  • Treatment for overdose is symptomatic and supportive and may include procedures such as gastric lavage or the administration of activated charcoal.
  • The official prescribing information notes that no specific antidote is known for nefazodone overdose.

Connection to the overall overdose profile:

Regulatory documents define the nefazodone overdose profile based on a spectrum of documented clinical signs, ranging from general malaise to severe CNS events. This profile dictates the mandated emergency response, explicitly requiring immediate medical assistance due to the potential for severe outcomes, especially in mixed overdoses. Since the regulatory text confirms the absence of a specific antidote, the primary official procedure is limited to documented supportive and symptomatic treatment until the patient is stabilized.

Therapeutic Uses of Serzone

Serzone: Therapeutic Uses and Treatment Benefits

Serzone, whose active ingredient is nefazodone hydrochloride, is a prescription medication indicated for the treatment of depression. The effectiveness of this medication has been established in controlled trials involving adult outpatients diagnosed with Major Depressive Disorder. The treatment of depression aims to address symptoms such as persistent depressed mood or a notable loss of interest or pleasure, which interfere with daily functioning.


Quick Facts

  • Treats depression.
  • Indicated for Major Depressive Disorder.
  • May help manage related symptoms like anxiety and sleep disturbances in depressed patients.

Clinical studies have shown Serzone to be superior to placebo in improving depression scores, including factors related to anxiety and sleep disturbances. The medication’s primary and established role is to aid in the recovery from acute depression and to help prevent its relapse over the longer term. However, due to the established risk of severe hepatic failure associated with its use, prescribers must carefully consider the use of Serzone, often reserving it for patients who have not responded adequately to other treatments.

Eligibility and Restrictions for Use

Eligibility Scope

Category Official Regulatory Status
Populations for whom use is allowed Adults (18 years of age and older) with the labeled condition.
Populations for whom use is not recommended Individuals with active liver disease or elevated baseline serum transaminases.
Populations for whom use is contraindicated Patients with a prior history of nefazodone-induced liver injury; patients with known hypersensitivity to nefazodone or other phenylpiperazine antidepressants; patients on MAOIs, pimozide, carbamazepine, or full doses of triazolam.
Age-related eligibility rules Not approved for pediatric patients (under 18 years); safety and efficacy have not been established. Older adults (>65 years) are generally started at a reduced initial dose.
Condition-specific eligibility rules Patients who develop evidence of hepatocellular injury (AST or ALT geq 3x ULN) must be withdrawn permanently. Renal impairment (specific clearances) does not require dosage adjustment.
Pregnancy and lactation eligibility status Pregnancy: Use is a relative contraindication or precaution (Category C). Lactation: Use not recommended; official labeling notes harmful infant effects.

Eligibility Classifications (High-Level)

Category Classification Details
Eligibility severity classification Absolute Contraindication (Liver injury history, MAOIs); Not Established (Pediatric); Relative Contraindication/Precaution (Active liver disease, Pregnancy, Lactation).
Eligibility-context constraints Exclusion based on hepatic integrity and concurrent use of strong CYP3A4-metabolized drugs.

Resulting Eligibility Structure

Official eligibility statements strictly limit use to the adult population and impose absolute prohibitions based on liver health. Treatment is contraindicated in any patient with a prior history of nefazodone-related liver injury or those with active liver disease, and it is not approved for anyone under the age of 18. Use is further limited by specific drug-drug interaction contraindications and necessitates caution in individuals with a history of seizures or risk factors for hypotension.

What should I know about interactions with other medicines?

Interactions with other medicines and products

Serzone's official interaction profile is structured around its ability to inhibit metabolism and its potential for combined central nervous system (CNS) effects. The official regulatory documents establish several mandated restrictions and use-conditions based on documented pharmacokinetic and pharmacodynamic interactions.

Contraindicated Combinations and Restrictions

Co-administration with Monoamine Oxidase Inhibitors (MAOIs) is contraindicated, requiring a mandatory washout period of at least 7 to 14 days when transitioning between therapies. The combination with the CYP3A4 substrate Pimozide is also contraindicated due to the risk of significantly increased plasma concentrations and cardiac events. The same restriction applies to full doses of Triazolam.

Pharmacokinetic and Pharmacodynamic Interactions

Serzone is documented as a potent inhibitor of the CYP3A4 enzyme, a pharmacokinetic pattern that increases the exposure of co-administered CYP3A4 substrates, including certain statins (e.g., Lovastatin, Simvastatin) and Digoxin. Conversely, co-administration with strong CYP3A4 inducers (e.g., Carbamazepine, Phenytoin) is documented to reduce Serzone plasma levels.

Official labeling advises caution regarding pharmacodynamic interactions with all CNS depressants, including alcohol, due to enhanced effects like drowsiness. Furthermore, geriatric patients show increased systemic exposure, which is an official label-based constraint.

Mechanism of Action

How Serzone Works

Serzone (nefazodone) functions through a multimodal pharmacodynamic action centered on the central serotonergic system. The mechanism involves a dual pharmacological profile: receptor antagonism and reuptake inhibition.

Serotonin Receptor Modulation

Nefazodone’s core action is the antagonism (blocking) of the postsynaptic 5-HT2 A receptor. This blockade is functional, preventing the natural neurotransmitter, serotonin, from activating this specific site. This interaction triggers a disinhibition cascade that facilitates the activity of other key serotonin receptors, such as the 5-HT1 A receptor. This molecular sequence gradually leads to a functional adjustment of serotonergic signaling within central neural circuits.

Ancillary Pathway Effects

In addition to receptor antagonism, the drug is a weak inhibitor of the Sodium-dependent Serotonin Transporter (SERT), which limits the reuptake of serotonin into the presynaptic neuron. The 5-HT2 A antagonism also influences the physiological processes governing sleep architecture. Furthermore, nefazodone exhibits an ancillary action of blocking the alpha1 adrenergic receptor. This ancillary activity influences specific peripheral autonomic signals involved in the regulation of vascular tone.

Dosage and Administration Information

How Serzone (Nefazodone) is Used: Official Administration Guidelines

Serzone, containing nefazodone hydrochloride, is strictly for oral administration as a tablet and is typically taken in a twice-daily regimen. Official guidelines emphasize a gradual and controlled process to establish the correct dose for maintenance.


Standard Adult Dosing Protocol

The established regimen begins with a relatively low dose that is incrementally increased to reach a therapeutic level. The tablet strengths available are 50 mg, 100 mg, 150 mg, 200 mg, and 250 mg.

Dosing Parameter Official Labeled Regimen
Starting Dose 200 mg per day, divided and taken as 100 mg twice daily
Maintenance Range 300 mg to 600 mg per day, administered in two divided doses
Maximum Daily Dose 600 mg

Administration and Adjustment Principles

The initiation phase requires careful titration; dose adjustments should not occur more frequently than once per week and should be made in increments of 100 mg to 200 mg per day until the desired response is achieved. The tablets may be administered without regard to meals.

For specific populations, the recommended starting dose is lower to account for potential differences in drug clearance. For older adults (over 65 years) and patients with hepatic impairment, treatment should be initiated at 100 mg per day (50 mg twice daily). For instances of a missed dose, the instruction is to skip the missed dose if it is almost time for the next scheduled dose, and not to double up to compensate.

Recent Clinical Evidence

Research Evidence / Overview of Studies for Serzone

Evidence for Use in Major Depressive Disorder

Research on Serzone (nefazodone) for the study of Major Depressive Disorder (MDD) has primarily involved Randomized Controlled Trials (RCTs). These short-term studies, typically lasting 6 to 10 weeks, were conducted in adult outpatients and aimed to examine outcomes related to systemic or functional imbalance. The research monitored changes in symptom severity using standardized clinician-administered scales, such as the Hamilton Rating Scale for Depression. In these studies, nefazodone was evaluated in comparison to both a placebo (an inactive substance) and active comparators, including older antidepressants like imipramine.

Findings from these initial short-term trials were mixed. Studies reported patterns observed in symptom severity and patient response rates. While some research reported patterns of change that differed from those observed in the placebo groups, a few trials showed that the measured changes were not statistically distinct from placebo. When compared to active drugs, studies reported measurements of change in symptom scores that were sometimes observed during the trial period. This means that the evidence base for acute treatment includes some variability in findings.

Evidence on Associated Symptoms: Anxiety and Sleep Disturbances

Beyond the outcomes related to core depressive symptoms, studies also explored outcomes related to anxiety and sleep disturbances. These findings are derived from the pooled analyses of the main acute-phase RCTs, where researchers examined specific symptom factors (e.g., agitation, insomnia) as measured within the overall symptom scales of the acute-phase RCTs.

For these associated symptoms, studies report how symptoms evolved in the observed populations. For instance, patterns related to the change in sleep disturbances and anxiety factor scores were often reported. Some data suggested that patterns of change in sleep, such as reports regarding early morning awakening, may occur in the early stages of study. It is important to note, however, that these specific symptom changes were observed in some studies only in the context of MDD and not as research for these symptoms as isolated conditions.


Long-Term Studies and Durability of Response

The evidence base for nefazodone includes studies designed to look beyond the initial 6 to 10 weeks of study, primarily through continuation and maintenance trials. These extended studies monitored patients who had already responded to acute treatment and followed them for up to one year to determine the time to relapse or recurrence of their depressive episode. Research describes patterns observed during these follow-up durations, which inform the evidence landscape regarding long-term outcomes.

Evidence in Specific Populations

The initial clinical trials primarily focused on adult outpatients diagnosed with MDD. Data for certain groups, particularly older adults (over 65), were limited in the core efficacy trials, meaning that dedicated research for this population remains sparse. Nefazodone was not studied for or approved for use in pediatric patients (children and adolescents). The existing research applies only to the populations studied.


What is Still Uncertain About the Evidence Base

Several research limitation frames apply to the existing data for Serzone. One primary limitation is the inconsistency observed in the initial acute efficacy trials, where some placebo-controlled research did not show a clear difference. Findings were mixed across studies, and researchers continue to explore the reasons for this variability. Furthermore, long-term outcomes are not fully established beyond the one-year mark of the maintenance trials. Data for certain groups remain insufficient, particularly for older adults, which means that the findings describe group patterns, not personal outcomes.

Frequently Asked Questions (FAQ)

Common questions about Serzone (FAQ)

Q: Is Serzone still manufactured and available in all countries?

The original brand name, Serzone, has been discontinued by the company that marketed it. However, the generic form, nefazodone, is still manufactured and available in the United States, though it was withdrawn from some other international markets like Canada and Europe.

Q: Why is Serzone sometimes prescribed instead of newer antidepressants?

Official information indicates that this medication is associated with a lower rate of sexual side effects compared to certain other antidepressant classes. This difference in side effect profiles may be a factor in why a healthcare provider selects this drug for an individual.

Q: How long does it usually take before a person may feel the effects of Serzone?

Studies and official information suggest that the therapeutic action of this medicine is typically not felt immediately. It often takes a period of time, usually between two to four weeks, before a person may notice noticeable symptomatic changes.

Q: What is the typical length of time a person stays on Serzone treatment?

According to clinical guidelines, treatment with this medication may be continued long-term. This strategy is employed to help prevent the recurrence or relapse of depressive symptoms over time.

Q: Can Serzone cause problems with blood pressure or heart rhythm?

Official labeling describes postural low blood pressure, known as orthostatic hypotension, as a common side effect of this medication. The medication's official labeling notes the need for caution when used in patients with heart conditions or other pre-existing health concerns that could be made worse by a drop in blood pressure.

Q: Are there any foods or drinks to avoid when taking Serzone?

Official regulatory documents identify the need to avoid consuming grapefruit or grapefruit juice while taking this medication. This restriction is due to the potential for these foods to interfere with the drug's metabolism, which could change the levels of the medicine in the body.

Q: What is the history of Serzone receiving a 'Black Box Warning' in the United States?

Official labeling includes a Boxed Warning regarding the rare but serious risk of life-threatening liver failure. Additionally, the medication carries a separate warning about the increased risk of suicidal thinking and behavior in young adults, adolescents, and children.

Q: What are the reported discontinuation symptoms of Serzone?

Regulatory information notes that stopping the medication suddenly can result in a withdrawal or discontinuation syndrome, which includes various physical and emotional symptoms. To manage this potential effect, official guidelines state that a gradual dose reduction (tapering) is necessary.

Q: What is the official description of what happens when a person stops taking Serzone?

Official administration guidelines state that abrupt discontinuation of the medication must be avoided. The labeling indicates that a gradual and systematic reduction in dosage is necessary to help prevent the onset of discontinuation symptoms and minimize the risk of depression symptom recurrence.

Q: Is Serzone chemically similar to any other well-known medications?

This medication's active ingredient, nefazodone, is a phenylpiperazine derivative that is chemically related to the drug trazodone. The official prescribing information notes that a prior history of hypersensitivity to other phenylpiperazine antidepressants is a contraindication to its use.

Q: How is the progress of Serzone treatment usually monitored?

Official guidelines state that treatment monitoring includes checks for liver function, often through blood tests, particularly in the initial months. Healthcare providers also routinely monitor for changes in behavior, the emergence of suicidal thoughts, and blood pressure.

Q: What does it mean for Serzone to be a serotonin and norepinephrine reuptake inhibitor and antagonist?

The medication's classification reflects its unique mechanism, which involves a dual action. It functions by blocking the 5-HT2 A serotonin receptor while also weakly limiting the reuptake of both serotonin and norepinephrine in the brain.

Q: Does grapefruit juice interact with Serzone?

Official regulatory documents indicate that grapefruit juice must be restricted while taking this medication. This is because grapefruit can interfere with the CYP3A4 enzyme, which is involved in breaking down the drug, potentially increasing the levels of the medication in the bloodstream.

Q: Do the side effects of Serzone usually lessen or go away after a few weeks?

Clinical information indicates that many common side effects are experienced when first starting the medicine. These effects, such as nausea or dry mouth, often lessen or resolve completely over time as the body adjusts to the medication.

Q: Is weight gain a potential side effect of Serzone?

In clinical trials, this medication was not commonly associated with changes in weight. However, as with many medications, weight changes have been reported during postmarketing surveillance.

Q: Are sexual side effects less common with Serzone compared to other antidepressant types?

Clinical evidence indicates that this medication is generally associated with a low incidence of sexual side effects. This is a common feature noted when comparing its profile to that of selective serotonin reuptake inhibitors ( SSRIs).

Q: Is it safe to take herbal supplements, like St. John's Wort, with Serzone?

Official labeling describes the combination of this medicine with herbal supplements like St. John's Wort as requiring caution. Regulatory information states that using them together may increase the risk of serious side effects, including a condition known as Serotonin Syndrome.

Q: Does having a history of mania or bipolar disorder affect eligibility for Serzone?

Official regulatory documents state that caution is required in patients who have a history of mania or bipolar disorder. The medication may precipitate a manic or hypomanic episode and is generally contraindicated for treating bipolar depression in the absence of a mood stabilizer.

Q: Is Serzone considered a drug with a high potential for dependence or addiction?

This medication is not classified as a controlled substance and is not considered to have a high potential to be habit-forming.

Q: What is the difference between Serzone and Trazodone?

Though chemically related, they have distinct mechanisms of action. Serzone is a serotonin and norepinephrine reuptake inhibitor and antagonist, whereas trazodone is primarily a serotonin antagonist. Serzone is generally known to be less sedating than trazodone.

Q: Is it possible for the benefits of Serzone to suddenly stop working during treatment?

While a sudden cessation of effect is not an expected event, an apparent loss of consistent efficacy over time may occur. Clinical guidelines suggest this observation could be a sign of an underlying or previously undiagnosed condition, such as bipolar disorder, which may need to be evaluated.

Q: What is the history of the approval process for Serzone?

Regulatory history shows that the active ingredient, nefazodone, was first approved for use in the United States in 1988. The approval was for the treatment of both moderate and severe major depressive disorder.

How should Serzone be stored and disposed of?

Nefazodone hydrochloride tablets must be stored at Controlled Room Temperature, which is officially defined as 20 C to 25 C (68 F to 77 F), with permitted brief excursions between 15 C and 30 C (59 F and 86 F).

Required Storage Conditions

  • Store the medicine in a closed, tightly closed container in a cool, dry place.
  • Protect the tablets from heat, moisture, and direct light. Keep from freezing.
  • The medication must be stored out of the reach of children.

Disposal of Unused Medicine

  • Disposal of unneeded or expired tablets must be conducted according to local regulations.
  • Do not keep outdated medicine or medicine no longer needed.
  • The medication should not be flushed down the toilet.

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

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