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Isocarboxazid Side Effects

Medically reviewed by Last updated on Aug 8, 2022.


Commonly reported side effects of isocarboxazid include: dizziness and headache. Other side effects include: suicidal ideation, suicidal tendencies, drowsiness, sleep disorder, tremor, nausea, and orthostatic hypotension. Continue reading for a comprehensive list of adverse effects.

Applies to isocarboxazid: oral tablet.


Oral route (Tablet)

Antidepressants increased the risk of suicidal thinking and behavior in children, adolescents, and young adults in short-term studies with major depressive disorder (MDD) and other psychiatric disorders. Short term studies did not show an increase in the risk of suicidality with antidepressants compared to placebo in adults beyond age 24, and there was a reduction in risk with antidepressants compared to placebo in adults aged 65 and older. This risk must be balanced with the clinical need. Monitor patients closely for clinical worsening, suicidality, or unusual changes in behavior. Families and caregivers should be advised of the need for close observation and communication with the prescriber. Not approved for use in pediatric patients.

Serious side effects of Isocarboxazid

Along with its needed effects, isocarboxazid may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking isocarboxazid:

Less common

  • Burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings
  • chills
  • cold sweats
  • confusion
  • difficult urination
  • dizziness, faintness, or lightheadedness when getting up from lying or sitting position
  • fainting
  • fast, irregular, pounding, or racing heartbeat or pulse
  • fear or nervousness
  • heavy feeling
  • increased need to urinate
  • passing urine more often
  • restlessness
  • shakiness in the legs, arms, hands, or feet
  • sudden jerky movements of the body
  • sweating
  • trembling or shaking of the hands or feet
  • trouble sitting still

Incidence not known

  • Agitation
  • burning while urinating
  • change in consciousness
  • decrease in frequency of urination
  • decrease in urine volume
  • decreased urine output
  • depression
  • difficulty in passing urine (dribbling)
  • dizziness
  • false or unusual sense of well-being
  • headache
  • hostility
  • irritability
  • loss of bladder control
  • loss of consciousness
  • muscle twitching
  • nausea
  • need to keep moving
  • numbness or tingling of the hands, feet, or face
  • rapid weight gain
  • seeing, hearing, or feeling things that are not there
  • seizures
  • shakiness and unsteady walk
  • stupor
  • swelling of the face, ankles, or hands
  • unsteadiness, trembling, or other problems with muscle control or coordination
  • unusual tiredness or weakness

Other side effects of Isocarboxazid

Some side effects of isocarboxazid may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

Less common

  • Decreased interest in sexual intercourse
  • drowsiness
  • inability to have or keep an erection
  • loss in sexual ability, desire, drive, or performance
  • relaxed and calm
  • sleepiness
  • sleeplessness
  • trouble sleeping
  • unable to sleep
  • unusual drowsiness, dullness, tiredness, weakness, or feeling of sluggishness

Incidence not known

  • Black tongue
  • blurred vision
  • change in vision
  • impaired vision
  • increased sensitivity of the skin to sunlight
  • itching
  • raised, dark red, wart-like spots on the skin, especially when used on the face
  • redness or other discoloration of the skin
  • severe sunburn
  • skin rash

For Healthcare Professionals

Applies to isocarboxazid: oral tablet.


Common (1% to 10%): Orthostatic hypotension, palpitations

Frequency not reported: Disturbances in cardiac rhythm, peripheral edema[Ref]

Orthostatic hypotension, disturbances in cardiac rhythm, and/or peripheral edema may be controlled by reducing the dose.[Ref]

Nervous system

Dizziness and/or drowsiness may be controlled by reducing the dose.[Ref]

Very common (10% or more): Dizziness (up to 29%), headache (up to 15%)

Common (1% to 10%): Drowsy/drowsiness, forgetful, hyperactive, lethargy, myoclonic jerks, paresthesia, sedation, syncope, tremor

Frequency not reported: Hyperreflexia, mild headache, overactivity, peripheral neuritis

Postmarketing reports: Akathisia, ataxia, coma, neuritis[Ref]


Common (1% to 10%): Constipation, diarrhea, dry mouth, nausea

Frequency not reported: Vomiting

Postmarketing reports: Black tongue[Ref]

Constipation, dry mouth, nausea, and/or vomiting may be controlled by reducing the dose.[Ref]


Blurred vision may be controlled by reducing the dose.

Toxic amblyopia was reported in a patient with schizophrenia who received this drug for approximately 1 year; however, no causal relationship to this drug was established.[Ref]

Frequency not reported: Blurred vision

Postmarketing reports: Toxic amblyopia[Ref]


Frequency not reported: Muscle tremor[Ref]


Common (1% to 10%): Impotence, urinary frequency, urinary hesitancy

Frequency not reported: Difficulty in micturition, impairment of erection and ejaculation

Postmarketing reports: Dysuria, incontinence, sexual disturbances, urinary retention[Ref]


The most common adverse events were dizziness, headache, nausea, and dry mouth.[Ref]


Postmarketing reports: Impaired water secretion compatible with syndrome of inappropriate secretion of antidiuretic hormone (SIADH)[Ref]


Common (1% to 10%): Sweating

Frequency not reported: Skin rashes

Postmarketing reports: Photosensitivity, spider telangiectases[Ref]


Insomnia may be controlled by reducing the dose.

Hallucinations have been reported with high doses, but have disappeared with dose reduction or discontinuation of therapy.[Ref]

Common (1% to 10%): Anxiety, insomnia, sleep disturbance

Frequency not reported: Agitation, behavioral changes, confusion, suicidal behavior, suicidal ideation

Postmarketing reports: Euphoria, hallucinations[Ref]


Fatigue and/or weakness may be controlled by reducing the dose.[Ref]

Common (1% to 10%): Chills, heavy feeling

Frequency not reported: Fatigue, weakness[Ref]


Rare (less than 0.1%): Blood dyscrasias, granulocytopenia, purpura

Postmarketing reports: Hematologic changes[Ref]


Frequency not reported: Increased appetite, weight gain[Ref]

Frequently asked questions


1. "Product Information. Marplan (isocarboxazid)." Roche Laboratories (2001):

2. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.