Nefazodone (Serzone)

What it treats

Nefazodone is approved by the U.S. Food and Drug Administration to treat depression.

Off-label uses include insomnia in the context of depression and, less often, PTSD-related sleep disturbance. Off-label means a purpose the label doesn't formally list even though evidence and practice support it.

How it works

Nefazodone acts on serotonin. It weakly slows serotonin reuptake, and it blocks the 5-HT2A receptor, a docking site on cells that serotonin uses. That combination is why sleep quality tends to improve without the dry mouth and constipation of tricyclics and without the sexual side effects of SSRIs.

As with other antidepressants, the effect isn't from the first dose. It comes from slower changes in the brain over the following weeks.

Receptor mechanism (detail)

Nefazodone is a SARI (serotonin antagonist and reuptake inhibitor), related to trazodone. It's a 5-HT2A antagonist and a weak SERT inhibitor. It also blocks alpha-1 adrenergic receptors and has active metabolites, including m-CPP (a serotonergic metabolite that can cause anxiety in some people, especially when CYP3A4 inhibitors slow its clearance).

Potency and typical dosing pattern

Ranges are typical framework only, not a prescription for any individual.

Starting is 100 mg twice a day. Usual range is 300 to 600 mg per day divided. The drug is dosed twice daily because of its half-life.

Safety monitoring

• Liver function tests at baseline and periodically. Elevated ALT/AST or symptoms of liver injury (jaundice, dark urine, abdominal pain, fatigue) should prompt stopping the drug and workup.
• Blood pressure, especially on standing (alpha-1 antagonism).
• Suicidality in the first 4 weeks, especially under age 25 (FDA boxed warning).
• Serotonin syndrome, avoid MAOIs.
• Drug interactions. Nefazodone is a strong CYP3A4 inhibitor and interacts with many medications.
• Reassess at 2, 4, and 6 to 8 weeks.

What to expect

Common side effects

Common side effects include:

• Drowsiness.
• Dry mouth.
• Dizziness on standing.
• Blurred vision.
• Nausea.
• Constipation.

If a side effect is severe, or it isn't improving, that's a conversation to have with the prescriber rather than a reason to stop on your own.

Serious side effects and warnings

This is where nefazodone deserves special attention.

Boxed warning: Liver failure. Rare cases of fulminant liver failure, some resulting in death or requiring liver transplant, have been reported. The reported rate is roughly 1 in 250,000 to 300,000 patient-years, but the outcome when it happens is grave. Patients should be told about symptoms of liver injury (jaundice, unusual fatigue, right-upper-abdominal pain, dark urine) and asked to report them promptly.

Boxed warning: Suicidality. Like all antidepressants, nefazodone carries an FDA boxed warning that it can increase suicidal thoughts and behaviors in children, teenagers, and young adults under 25, especially in the first weeks of treatment.

• Orthostatic hypotension. A drop in blood pressure on standing.
• Serotonin syndrome. Do not combine with MAOIs.
• Drug interactions. Nefazodone strongly inhibits CYP3A4, which changes levels of many co-administered drugs (statins, some benzodiazepines like alprazolam and triazolam, carbamazepine, tacrolimus, and others).

Sexual side effects

Nefazodone has among the lowest rates of sexual side effects of any antidepressant. Reduced desire, delayed orgasm, or arousal difficulty are uncommon. That profile is one of the drug's main appeals when it's used.

Weight, appetite, and sleep

Nefazodone tends to be weight-neutral. It's sedating, which is why it's often taken with the largest share at bedtime and why it can help sleep in the context of depression.

Starting and dosing basics

This section is general background, not a dosing instruction for any individual. The right dose is a decision for a prescriber.

Nefazodone comes as tablets. Starting doses are low, with steps up over days to weeks. Because of the liver risk, a baseline liver panel and periodic monitoring are standard. Any symptoms of liver injury prompt stopping the drug and evaluation.

Missed doses and interactions

If you miss a dose, take it when you remember, unless it's almost time for the next dose. Skip the missed dose and carry on. Don't take two doses to make up for one.

Interactions are extensive because nefazodone is a strong CYP3A4 inhibitor. Do not combine with cisapride, pimozide, alprazolam, triazolam, or several statins because levels can rise dangerously. Do not combine with MAOIs. Other serotonergic drugs raise serotonin syndrome risk. Alcohol adds to CNS effects and stresses the liver. Give every prescriber and pharmacist a full list of your medications and supplements, including over-the-counter ones.

Stopping and tapering

Nefazodone isn't a controlled substance and isn't habit-forming in the usual sense.

The body does adjust to it, and stopping abruptly can cause discontinuation symptoms: dizziness, sleep disturbance, and irritability. A gradual taper planned with a prescriber avoids most of this.

Pregnancy and breastfeeding

This is an area where individual circumstances matter and the decision belongs with a clinician. Untreated depression carries its own risks during pregnancy, and nefazodone passes into breast milk. Anyone who is pregnant, planning a pregnancy, or breastfeeding should talk it through with their prescriber so the specific risks and benefits can be weighed for their situation.

Cost and generic availability

Nefazodone is available as a generic. The brand name Serzone was withdrawn from several markets after the liver-failure signal, but the generic remains available in the U.S. Costs are typically modest.

Common questions

Why isn't nefazodone used more often? The boxed warning for rare but serious liver failure has pushed most prescribers toward safer options. When sexual side effects are the main problem with other antidepressants, some prescribers still consider it.

How likely is liver failure? The reported rate is roughly 1 in 250,000 to 300,000 patient-years. Rare, but the outcome when it happens is severe.

Why does it help sleep? Blocking 5-HT2A receptors improves sleep architecture. Nefazodone also blocks alpha-1 and has some histamine effect, adding to the sedation.

Does it cause sexual side effects? Rarely, which is one of its distinctive features.

Is it addictive? No. It's not a controlled substance and doesn't cause cravings. Stopping should still be done gradually.

Questions to ask your prescriber

• Given the liver warning, why nefazodone specifically for me?
• What's the plan for liver function monitoring?
• Which symptoms should prompt me to call or go to the emergency room?
• Do any of my other medications interact with nefazodone?
• If we decide to stop it later, how would we do that safely?

Sources

This guide draws on current prescribing information and public health references and current as of June 8, 2026. It is reviewed for clinical accuracy and updated as guidance changes.

• U.S. Food and Drug Administration. Nefazodone hydrochloride (Serzone) prescribing information.
• MedlinePlus, U.S. National Library of Medicine. Nefazodone.
• National Institute of Mental Health. Mental health medications.
• American Psychiatric Association. Practice Guideline for the Treatment of Patients with Major Depressive Disorder.
• National Institute for Health and Care Excellence (NICE). NG222, Depression in adults.