Potential Side Effects of Haldol (Haloperidol)

many rubbing his eyes as a medication side effect
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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.

It's important to be aware of the possible effects listed below, but also to let your doctor know if you have any physical changes which concern you. Unfortunately, most of the drugs used to treat psychosis carry some side effects.

Choosing a medication to treat psychosis is often a process of choosing which side effects you are most able to tolerate.

Emergency Haldol Side Effects

There are some side effects of Haldol, that while uncommon, are potentially extremely serious. If you note any of these emergency side effects, stop taking your Haldol and call for emergency help immediately. In the case of some of these side effects, such as seizures, you may be unable to call yourself.

Make sure that your friends and loved ones know about these possible side effects and to call if they should see you experiencing any of them. Potential effects include:

  • 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

Some of the following side effects may less serious, but should prompt you to call your doctor as soon as possible.

More common serious side effects include:

  • 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 serious side effects include:

  • 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

Rare but serious side effects:

  • 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 (jaundice)

Less Serious (Mild) Haldol Side Effects

There are several less serious side effects that people may experience while using Haldol. Though these are not an emergency or don't usually mean that you need to stop the medication, talk to your doctor if you find them bothersome. There are sometimes simply measures you can take to either cope with these side effects or help them to go away, for example, by using sunscreen when you are out of doors.

More common mild 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 mild side effects:

  • Decreased sexual ability
  • Drowsiness
  • Increased sun sensitivity (involving skin rash, itching, redness or other skin discoloration, or severe sunburn)
  • Nausea or vomiting

Tardive Dyskinesia With Haldol

Treatment with Haldol can cause a movement disorder called tardive dyskinesia. This disorder is thought to occur due to an 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.

Unfortunately, this side effect is far too common. In the past, it was thought that almost one in 10 to one in 20 people might develop tardive dyskinesia one year after starting the medication.

Research shows that other drugs for bipolar disorder 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.

You may wish to go over the alternative medications that are available and determine which ones have a side effect profile that you find would be more tolerable for you.

For those who need to take Haldol, research is in progress looking at methods of decreasing the risk of tardive dyskinesia. Many of the studies, such as those looking at antioxidants such as Ginkgo biloba or alpha-tocopherol (a type of vitamin E), have only been done on animals in the lab, but it's likely we will soon learn more about how to protect people from these side effects. Before starting the medication, talk to your doctor about any options she feels may decrease your risk.​

Overdose and Discontinuation of Haldol

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.

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