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Nefazodone Side Effects

It is possible that some side effects of nefazodone may not have been reported. These can be reported to the FDA here. Always consult a healthcare professional for medical advice.

For the Consumer

Applies to nefazodone: oral tablet

As well as its needed effects, nefazodone may cause unwanted side effects that require medical attention.

If any of the following side effects occur while taking nefazodone, check with your doctor or nurse as soon as possible:

More common
  • Blurred vision or other changes in vision
  • clumsiness or unsteadiness
  • lightheadedness or fainting
  • ringing in the ears
  • skin rash or itching
Less common
  • Bladder pain
  • bloody or cloudy
  • cough or hoarseness
  • diarrhea
  • excessive muscle tone
  • eye pain
  • feeling dizzy
  • frequent urge to urinate
  • itching of the vagina or genital area
  • muscle stiffness
  • muscle tension or tightness
  • nausea
  • pain during sexual intercourse
  • painful, burning, or difficult urination
  • shortness of breath, tightness in chest, or wheezing
  • stomach pain
  • thick, white vaginal discharge with no odor or with a mild odor
  • troubled breathing
  • Asthma
  • bleeding from the rectum
  • bloody or black, tarry stools
  • change in sexual desire or performance
  • chest pain
  • double vision
  • dryness of eye
  • ear pain
  • fainting
  • fast heartbeat
  • fever, chills, or sore throat
  • hallucinations (seeing, hearing, or feeling things that are not there)
  • hives
  • increased sense of hearing
  • increased sensitivity to sun
  • irritation or soreness of mouth
  • joint or muscle pain or stiffness
  • kidney stones
  • large pupils of eyes
  • lower back, side, or stomach pain
  • menstrual changes
  • mood or mental changes
  • nerve pain or twitching
  • pelvic pain
  • problems in speaking
  • problems with urination
  • prolonged, painful, inappropriate penile erection
  • red or irritated eyes
  • sensitivity of eyes to light
  • swelling of face
  • swollen glands
  • talking, feeling, and acting with excitement and activity you cannot control
  • unusual bleeding or bruising
  • unusual feeling of well-being
  • unusual tiredness or weakness
  • vomiting of blood or material that looks like coffee grounds
Incidence not known
  • Blistering, peeling, or loosening of skin
  • light-colored stools
  • confusion
  • dark urine
  • decreased urine output
  • fever
  • increased thirst
  • itching
  • lack of appetite
  • large, hive-like swelling on face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
  • muscle pain or cramps
  • muscle spasm or jerking of all extremities
  • muscle stiffness
  • pain, warmth, or burning in fingers, toes, and legs
  • red skin lesions, often with a purple center
  • sore throat
  • sudden loss of consciousness
  • sweating
  • vomiting

Some nefazodone side effects may not need any medical attention. As your body gets used to the medicine these side effects may disappear. Your health care professional may be able to help you prevent or reduce these side effects, but do check with them if any of the following side effects continue, or if you are concerned about them:

More common
  • Abnormal dreams
  • agitation
  • confusion
  • constipation
  • diarrhea
  • dizziness
  • drowsiness
  • dryness of mouth
  • flushing or feeling of warmth
  • headache
  • heartburn
  • increased appetite
  • increased cough
  • memory problems
  • nausea
  • swelling of arms or legs
  • tingling, burning, or prickly sensations
  • tremor
  • trouble in sleeping
  • vomiting
Less common or rare
  • Breast pain
  • generalized slowing of mental and physical activity
  • increased thirst
  • loss of strength or energy
  • muscle weakness
Incidence not known
  • Unexpected or excess milk flow from breasts
  • swelling of the breasts or breast soreness in males

For Healthcare Professionals

Applies to nefazodone: oral tablet

Nervous system

The manufacturer reports that during premarketing testing, two cases of seizures occurred. In the first case, a patient with a history of petit mal seizures experienced a petit mal seizure. In the second case a non- study participant took 2000 to 3000 mg of nefazodone with methocarbamol and alcohol and experienced a convulsion. The characteristics of the convulsion were not documented.

Nearly all selective serotonin reuptake inhibitors, mixed serotonin/norepinephrine reuptake inhibitors, and tricyclic antidepressants cause sleep abnormalities to some extent. These antidepressants have marked dose-dependent effects on rapid eye movement (REM) sleep, causing reductions in the overall amount of REM sleep over the night and delays the first entry into REM sleep (increased REM sleep onset latency (ROL)), both in healthy subjects and depressed patients. The antidepressants that increase serotonin function appear to have the greatest effect on REM sleep. The reduction in REM sleep is greatest early in treatment, but gradually returns towards baseline during long-term therapy; however, ROL remains long. Following discontinuation of therapy the amount of REM sleep tends to rebound. Some of these drugs (i.e., bupropion, mirtazapine, nefazodone, trazodone, trimipramine) appear to have a modest or minimal effect on REM sleep.[Ref]

Nervous system side effects are common and include somnolence in as many as 28% of treated patients. Dizziness, lightheadedness, sleep abnormalities, confusion, headache, fatigue, akathisia, and asthenia have also been reported. Activation of mania and seizures, and serotonin syndrome have occurred rarely.[Ref]


Gastrointestinal side effects including nausea (up to 32% of patients treated with high doses) have been reported.[Ref]

Nausea has not generally been associated with vomiting and tends to diminish with ongoing treatment.[Ref]


Ocular side effects including blurred vision (9%), and abnormal vision (scotomata and visual trails) (7%) have been reported.[Ref]


Hepatic side effects including cases of liver failure have been reported rarely but have sometimes been fatal.[Ref]


Cardiovascular side effects including postural hypotension (1% to 5.1%) and angioedema have been reported.[Ref]


Genitourinary side effects including impotence, urinary frequency, and urinary retention have been reported. One case of spontaneous ejaculation has also been reported.[Ref]

Priapism has not been reported in association with nefazodone therapy but has been associated with use of the related antidepressant trazodone.[Ref]


Anticholinergic side effects including dry mouth, blurred vision, and constipation have been reported, although much less frequently than with many other antidepressants.[Ref]

Other side effects including an increase in REM sleep (in contrast to the effects of most other antidepressants) have been reported.[Ref]


Endocrine side effects including galactorrhea, gynecomastia, and increased prolactin levels have been reported.[Ref]


Psychiatric side effects have included two cases of mania. A case of increased anxiety in a patient with panic disorder on low dose nefazodone has also been reported.[Ref]


Hypersensitivity side effects including anaphylactic reactions have been reported.[Ref]


Dermatologic side effects including Stevens-Johnson syndrome have been reported.[Ref]


Metabolic side effects including hyponatremia have been reported.[Ref]


Hematologic side effects including thrombocytopenia have been reported.[Ref]


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2. Cyr M, Brown CS "Nefazodone: its place among antidepressants." Ann Pharmacother 30 (1996): 1006-12

3. "Product Information. Serzone (nefazodone)." Bristol-Myers Squibb, Princeton, NJ.

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5. Rickels K, Schweizer E, Clary C, Fox I, Weise C "Nefazodone and imipramine in major depression: a placebo-controlled trial." Br J Psychiatry 164 (1994): 802-5

6. D'Amico MF, Roberts DL, Robinson DS, Schwiderski UE, Copp J "Placebo-controlled dose-ranging trial designs in phase II development of nefazodone." Psychopharmacol Bull 26 (1990): 147-50

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8. ArandaMichel J, Koehler A, Bejarano PA, Poulos JE, Luxon BA, Khan CM, Ee LC, Balistreri WF, Weber FL "Nefazodone-induced liver failure: Report of three cases." Ann Intern Med 130 (1999): 285-8

9. Schirren CA, Baretton G "Nefazodone-induced acute liver failure." Am J Gastroenterol 95 (2000): 1596-7

10. Hanno PM, Lopez R, Wein AJ "Trazodone-induced priapism." Br J Urol 61 (1988): 94

11. Sacks M, Miller F, Gunn J, Paul E, Sellew A "Unusual erectile activity as a side effect of trazodone." Hosp Community Psychiatry 36 (1985): 298

12. Scher M, Krieger JN, Juergens S "Trazodone and priapism." Am J Psychiatry 140 (1983): 1362-3

13. Patt N "More on trazodone and priapism." Am J Psychiatry 142 (1985): 783-4

14. Raskin DE "Trazodone and priapism." Am J Psychiatry 142 (1985): 142-3

15. Michael A, Ramana R "Nefazodone-induced spontaneous ejaculation." Br J Psychiatry 169 (1996): 672-3

16. Warner MD, Peabody CA, Whiteford HA, Hollister LE "Trazodone and priapism." J Clin Psychiatry 48 (1987): 244-5

17. Pescatori ES, Engelman JC, Davis G, Goldstein I "Priapism of the clitoris: a case report following trazodone use." J Urol 149 (1993): 1557-9

18. Sharpley AL, Walsh AE, Cowen PJ "Nefazodone--a novel antidepressant--may increase REM sleep." Biol Psychiatry 31 (1992): 1070-3

19. Armitage R, Rush AJ, Trivedi M, Cain J, Roffwarg HP "The effects of nefazodone on sleep architecture in depression." Neuropsychopharmacology 10 (1994): 123-7

20. Wilson S, Argyropoulos S "Antidepressants and sleep: a qualitative review of the literature." Drugs 65 (2005): 927-47

21. Walsh AE, Hockney RA, Campling G, Cowen PJ "Neuroendocrine and temperature effects of nefazodone in healthy volunteers." Biol Psychiatry 33 (1993): 115-9

22. Strohle A, Ehrenthal HD "Nefazodone may increase anxiety in panic disorder." J Clin Psychopharmacol 22 (2002): 95

23. Dubin H, Spier S, Giannandrea P "Nefazodone-induced mania." Am J Psychiatry 154 (1997): 578-9

24. Jeffries JJ, Aljeshi A "Nefazodone-induced mania." Can J Psychiatry 40 (1995): 218

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.