10 Haldol Side Effects You Should Know About

Haldol (haloperidol) is an antipsychotic medication that treats certain behavioral and mood disorders in adults and children. While Haldol is an effective treatment option, it also has several side effects to be aware of.

Below, we’ll take a closer look at 10 possible Haldol side effects, how to manage them, and when to speak with your healthcare provider.

1. Uncontrolled body movements

Several antipsychotics, including Haldol, can cause uncontrolled body movements. These are also known as extrapyramidal symptoms (EPS). They happen because Haldol blocks dopamine, a chemical in the brain that helps your muscles move properly.

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There are several types of EPS that can happen when you’re taking Haldol: 

• Acute dystonia: This can cause muscle spasms or stiff muscles. You may also notice abnormal eye movements. These symptoms usually happen within the first 5 days of starting Haldol or an increase in dose.

• Akathisia: The main symptoms of akathisia is an inability to sit still. You may have an overall feeling of restlessness. You may also feel a need to tap your foot, shake your leg, or do a similar repetitive motion for long periods of time. These symptoms usually appear after days to months of taking Haldol.

• Parkinsonism: These symptoms include tremor, movements that are slower than usual, and stiff or rigid muscles. They usually appear after you’ve been taking Haldol for several days to months.

• Tardive dyskinesia: These symptoms typically develop after years of taking Haldol. They include face movements you can’t control, such as lip smacking, tongue movements, and excessive eye blinking. It can also affect muscles in other parts of your body. Tardive dyskinesia is a serious condition, and you’ll likely need to stop taking Haldol if it happens.

EPS from Haldol can be challenging to deal with. And in some cases, they may interfere with your ability to eat, drink, or move the way you normally would. But these symptoms can often be managed with a change in your dosage or a switch to a different antipsychotic medication. Your healthcare provider may also prescribe other medications to help manage EPS while you’re taking Haldol. So be sure to let them know if any of these symptoms appear.

2. Drowsiness

Drowsiness is a common Haldol side effect. Along with feeling sleepy, you may also have trouble thinking clearly. This may make it harder to perform tasks that require your full attention, such as driving or cooking. So it’s best to avoid these activities until you know how Haldol affects you. It can also make falls more likely, so take care to move slowly and use furniture or handrails for support if needed.

Adding some caffeine to your morning routine may help with drowsiness, if your provider OK’s it. If drowsiness is severe, your provider may lower your Haldol dosage or recommend another treatment to help you stay awake during the day.

3. Dizziness

Dizziness is a relatively common side effect when you’re first starting Haldol. Signs of dizziness include feeling lightheaded, faint, or unsteady on your feet.

Sudden movements can make dizziness worse. This is called orthostatic hypotension, and it’s caused by a sudden drop in blood pressure when switching positions too quickly. To manage this, move slowly when getting up from a sitting or lying-down position. Staying well hydrated can also help prevent dizziness. As with drowsiness, avoid activities such as driving until your dizziness improves enough to do them safely.

Talk to your healthcare provider if you experience severe or frequent spells of dizziness, or if it doesn’t improve over time. Get immediate medical attention if your dizziness is accompanied by chest pain, shortness of breath, or fainting. There could be something more serious going on.

4. Weight gain

Weight gain is a well-known side effect of antipsychotic medications, including Haldol. But it seems to be less common with Haldol than with other antipsychotics.

There are several steps you can take to help prevent and manage weight gain while you’re taking Haldol. Try to eat a healthy diet, exercise regularly, and limit how much alcohol you drink. If these options aren’t working for you, reach out to your healthcare provider. They may want to add a medication to help you manage your body weight. Or they may want you to try a different antipsychotic medication.

5. Dry mouth

Haldol can cause dry mouth for some people taking it. This happens because Haldol has an anticholinergic effect on the body. It blocks a chemical messenger called acetylcholine and stops it from working. This leads to a decrease in the amount of saliva your mouth makes, causing dry mouth.

There are some at-home treatments you can try to help manage dry mouth. Try sipping on cold water throughout the day, chewing sugar-free gum, or sucking on ice chips. Having good oral hygiene and avoiding alcohol can help, too. But if home remedies aren’t helping, you can try an over-the-counter (OTC) saliva substitute, such as Biotene.

6. Constipation

Constipation is another potential side effect of Haldol. It’s also due to Haldol’s anticholinergic effects.

Eating enough fiber, staying hydrated, and exercising regularly can all help prevent and manage constipation. You can also try an OTC treatment option if needed. If your constipation doesn’t improve, be sure to let your provider know. You may need a prescription medication to manage it or a change in your antipsychotic treatment.

7. Sexual side effects

Some people may experience sexual side effects while taking Haldol. This includes a lower sex drive than usual and/or erectile dysfunction (ED). This can be awkward to talk about, but it’s common with certain antipsychotic medications. And your healthcare provider can help manage these side effects if you let them know they’re an issue for you.

Your provider may prescribe a different medication or adjust your dosage. They may also prescribe a medication to help treat ED so you can continue taking Haldol.

8. Gynecomastia

Gynecomastia, or male breast growth, is another possible Haldol side effect. Haldol raises levels of prolactin, a hormone that causes breast development. This can lead to breast growth in males who take it. While this isn’t physically harmful, it can cause distress for some people.

If you experience this side effect, your healthcare provider can help you manage it. They may prescribe a medication to help lower prolactin levels. Or they may suggest switching from Haldol to a different medication. 

9. Changes in blood pressure and heart rate

You may experience changes in your blood pressure and heart rate while taking Haldol. Some of these changes are mild, and may simply cause dizziness as mentioned above. But more serious heart problems are also possible. These side effects are rare, and they’re more likely with higher doses of Haldol or if you have a history of heart disease.

If you notice changes in your heartbeat, let your provider know right away. If you also have chest pain or trouble breathing, call 911 or seek emergency care.

10. Neuroleptic malignant syndrome

One rare but serious side effect of Haldol is neuroleptic malignant syndrome (NMS). NMS is a severe reaction to certain medications, including antipsychotics. The most common NMS symptoms include:

• Fever

• Stiff or rigid muscles

• Confusion

• Fast or uneven heart rate

If you develop any of these symptoms while taking Haldol, get immediate medical attention. NMS is a medical emergency that requires prompt treatment.

Good to know: Haldol can make heat stroke more likely while you’re taking it. And heat stroke symptoms are often similar to NMS symptoms. Try to avoid long periods of time outdoors in hot weather without proper sun protection while you’re taking Haldol. Seek shade whenever possible, and stay hydrated. If symptoms appear, seek medical care right away.

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Written by:

Alex Evans, PharmD, MBA

Alex Evans, PharmD, MBA, has been a pharmacist for 12 years. His first job was floating in a community chain pharmacy.

Edited by:

Stacia Woodcock, PharmD

Stacia Woodcock, PharmD, is a pharmacy editor for GoodRx. She earned her Doctor of Pharmacy degree from the University of Kentucky and is licensed in New York and Massachusetts.

Reviewed by:

Joshua Murdock, PharmD, BCBBS

Joshua Murdock, PharmD, BCBBS, is a licensed pharmacist in Arizona, Colorado, and Rhode Island. He has worked in the pharmacy industry for more than 10 years and currently serves as a pharmacy editor for GoodRx.

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