Potential Side Effects of Haloperidol (Haldol)

Haldol (haloperidol) is a typical antipsychotic drug used to treat schizophrenia and schizoaffective disorder, psychosis, agitation, and acute manic episodes associated with bipolar disorder. Haloperidol can also help with motor and verbal tics in people with Tourette's syndrome.

Haldol is generally part of a long-term treatment plan. Once symptoms have been eased by taking tablets daily, long-acting injections can help keep those symptoms at bay by providing a slow release of the drug.

While haloperidol can be an effective treatment, it also carries the risk of significant side effects. If you or a loved one is taking haloperidol, you should be aware of these potential side effects, some of which are medical emergencies.

All drugs used to treat psychosis carry some risk of side effects. Choosing the right psychosis medication for you is often a process of deciding which side effects you are willing (and able) to tolerate.

Common Side Effects

Approximately 70% of people taking haloperidol will have at least one adverse effect. This is roughly double the number of people who experience adverse side effects when taking low-potency antipsychotics such as chlorpromazine, thioridazine, and levomepromazine.

Some of the most common side effects of haloperidol include:

  • Involuntary movements
  • Tremors
  • Muscle stiffness
  • Drowsiness or sleepiness
  • Slow movements
  • Constipation
  • Dry mouth or excessive salivary secretions

When compared to other antipsychotic medications, haloperidol carries the greatest risk of neurological effects. These effects often appear within a few hours but can show up any time within the first five days of beginning or increasing the dosage of this drug.

Let your healthcare provider know if you experience these side effects and they become particularly bothersome. Your provider may lower the dosage of Haldol to minimize these effects, prescribe an additional medication to provide relief, or switch you to another antipsychotic drug.

Tardive Dyskinesia

Haloperidol can cause a movement disorder called tardive dyskinesia, affecting an estimated 24% to 32% of people taking this medication. This disorder is thought to occur due to increased brain sensitivity to the neurotransmitter dopamine.

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.

If this is a concern, you may wish to go over alternative medications that are available for your condition. Based on your options, your healthcare provider can help determine which ones have a side effect profile that would be more tolerable for you.

For those who need to take haloperidol, research is looking at ways to decrease tardive dyskinesia risk.

Serious Side Effects of Haloperidol

Some Haldol side effects are rare and more serious. Potentially serious side effects of haloperidol include:

  • Blurry vision
  • Loss of menstruation in females
  • Breast milk production
  • Loss of sex drive or sexual dysfunction in males
  • Body temperature regulation issues

Case studies have also suggested that taking haloperidol may result in facial edema, itchy skin lesions, and abdominal pain. If you develop any of these serious side effects after taking Haldol, contact your healthcare provider immediately to discuss your options.

Emergency Side Effects

There are also a few side effects that, if experienced, should prompt you or your loved one to stop taking haloperidol and seek immediate medical attention as they can be life-threatening. Emergency side effects include:

  • Irregular heartbeat
  • Confusion
  • Fever
  • Extreme muscle stiffness
  • Sweating

If you are the one taking haloperidol, talk to your friends and loved ones about these possible side effects so they know to call for help should they see you experiencing any of them.

Allergic Reactions

In addition to haloperidol's side effects, it's also possible to be allergic to this drug. Signs of a drug allergy include skin rash or hives, itching, swelling of the lips and tongue, and difficulty breathing. If an allergic reaction is suspected, seek immediate medical attention.

Taking Haloperidol Safely

If you are prescribed haloperidol, taking it safely involves using it as directed, as well as being aware of its precautions and interactions with other drugs.

Use as Directed

When taking haloperidol in pill or oral solution form, it is usually prescribed to be taken two or three times per day. Haloperidol injections are administered by a healthcare provider and are generally given every three to four weeks.

Take oral haloperidol around the same time each day. Also, don't take more or less than prescribed. If you miss a dose, take it as soon as you remember—unless it's close to the time for your next dose, in which case you should skip it and continue with your normal schedule.

Precautions

Haloperidol has not been deemed safe for certain populations. This includes:

If you have any of these conditions, talk with your healthcare provider before taking Haldol to make sure this medication is safe for you.

Black Box Warning

Older patients (aged 65 and older) with dementia-related psychosis are at increased risk of death when taking Haldol. The U.S. Food and Drug Administration (FDA) has labeled all antipsychotics with a "black box" warning, citing this risk and serving as a reminder that they are not approved to treat dementia symptoms. A black box warning is the most serious warning given by the FDA.

Interactions

Haloperidol may interact with other medications, either blocking or enhancing their effects or, in some cases, increasing your risk of developing other health issues (such as heart problems). Medications that may potentially interact with haloperidol include:

  • Antiarrhythmics
  • Blood pressure medicines
  • Medications for Parkinson's disease
  • Other antipsychotics

This drug can also be affected by some drugs, causing its levels to increase or decrease. Let your healthcare provider know if you are taking any other medications, vitamins, or supplements to help avoid any possible interactions.

Side Effects of Withdrawal

When discontinuing haloperidol, you may experience withdrawal. Withdrawal symptoms can begin within the first one to two days of stopping the drug and last up to two weeks, if not longer, and include:

  • Agitation
  • Anxiety
  • Decreased libido
  • Depression
  • Dizziness
  • Headaches
  • Increased heart rate
  • Insomnia
  • Nausea or vomiting
  • Sweating
  • Tremors
  • Trouble concentrating

If you experience any of these side effects of haloperidol withdrawal, notify your healthcare provider immediately.

Signs of Overdose

Symptoms of a haloperidol overdose, which can occur from taking too much of this drug or through drug interaction, include:

  • Jerking
  • Severe breathing difficulty
  • Severe dizziness
  • Severe drowsiness
  • Severe muscle trembling
  • Severe, unusual tiredness or weakness
  • Stiffness or uncontrolled movements

If you experience any of these symptoms, seek emergency medical assistance.

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11 Sources
Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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