Possible Side Effects from Haldol (Haloperidol)

Side effects of Haldol
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Haldol — generic name haloperidol — is a typical antipsychotic drug effectively used in the management of mania, agitation and hyperactivity in various mental illnesses, including bipolar disorder.

While Haldol can be an effective treatment, it also carries the risk of significant side effects. A patient taking Haldol or haloperidol should be aware of the potential side effects of this medication, some of which are medical emergencies.

Emergency Haldol Side Effects

These side effects are rare, but are extremely serious. Stop taking Haldol and get emergency help immediately if any of the following side effects occur:

  • convulsions (seizures from neuroleptic malignant syndrome)
  • difficult or fast breathing
  • fast heartbeat or irregular pulse
  • high fever
  • high or low blood pressure
  • increased sweating
  • loss of bladder control
  • severe muscle stiffness
  • unusually pale skin
  • unusual tiredness or weakness

Potentially Serious Side Effects

Notify your doctor as soon as possible if you experience any of these symptoms.

More common:

  • difficulty in speaking or swallowing
  • inability to move eyes
  • loss of balance control
  • mask-like face
  • muscle spasms, especially in the neck and back
  • severe restlessness or need to keep moving
  • shuffling walk
  • stiffness of arms and legs
  • trembling and shaking of fingers and hands
  • twisting body movements
  • weakness of arms and legs

Less common:

  • decreased thirst
  • difficulty urinating
  • dizziness, lightheadedness or fainting
  • hallucinations
  • lip smacking or puckering
  • puffing of cheeks
  • rapid or worm-like tongue movements
  • skin rash
  • uncontrolled chewing movements
  • uncontrolled arm and leg movements


  • confusion
  • hot, dry skin or lack of sweating
  • increased blinking or eyelid spasms
  • muscle weakness
  • sore throat and fever
  • uncontrolled twisting movements of neck, trunk, arms or legs
  • unusual bleeding or bruising
  • unusual facial expressions or body positions
  • yellow eyes or skin

Less Serious Haldol Side Effects

If you experience these side effects from Haldol and find they're bothersome, talk to your doctor about them.

More common side effects:

  • blurred vision
  • changes in menstrual period
  • constipation
  • mouth dryness
  • breast swelling or pain in women
  • unusual secretion of milk from breasts
  • weight gain

Less common side effects:

Tardive Dyskinesia with Haldol

Treatment with Haldol can cause a movement disorder called tardive dyskinesia. Signs of tardive dyskinesia include fine, worm-like movements of the tongue, or other uncontrolled movements of the mouth, tongue, cheeks, jaw, or arms and legs. These symptoms may not go away after you stop taking the drug.

In one study, more than 7% of patients taking Haldol suffered from tardive dyskinesia one year after they started the medication.

Research shows that other drugs for bipolar disorder and other psychiatric conditions may not have as great a risk of tardive dyskinesia as Haldol. If you're concerned about your risk, talk to your doctor about your medication options.

Haldol Overdose and Discontinuation

When you're discontinuing Haldol, you may experience trembling in your fingers and hands, along with uncontrolled movements of your mouth, tongue and jaw. If you do have these side effects, notify your doctor as soon as possible.

Symptoms of a Haldol overdose include severe breathing difficulty; severe dizziness; severe drowsiness; severe muscle trembling, jerking, stiffness or uncontrolled movements; and severe, unusual tiredness or weakness. If you experience these symptoms, seek emergency medical assistance.


Beasley CM et al. Randomised double-blind comparison of the incidence of tardive dyskinesia in patients with schizophrenia during long-term treatment with olanzapine or haloperidol. British Journal of Psychiatry. 1999 Jan;174:23-30.

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