• Haloperidol may be used to treat psychotic thoughts or symptoms. Experts aren't sure exactly how haloperidol works to reduce psychotic thoughts or symptoms or control tics in Tourette syndrome, but suggest it helps to rebalance neurotransmitters such as dopamine in the brain.
• Haloperidol belongs to the class of medicines known as butyrophenone antipsychotics. It may also be referred to as a typical, conventional, or miscellaneous antipsychotic.

• May be used in the treatment of schizophrenia.
• May help control tics and vocal utterances of Tourette syndrome. Some studies have reported a 78-91% reduction in tics.
• Available as oral tablets and as an injection. The injection is not approved for intravenous administration.
• Generic haloperidol is available.

If you are between the ages of 18 and 60, take no other medication or have no other medical conditions, side effects you are more likely to experience include:

• Extrapyramidal side effects such as akathisia (a feeling of inner restlessness), Parkinsonism (eg, mask-like face, restlessness, shuffling gait), blurred vision, breast discharge, constipation, dry mouth, dystonia (prolonged abnormal muscle contractions), missed menstrual periods, swallowing difficulties, weakness, and weight gain are some of the more common side effects.
• Haloperidol may cause tardive dyskinesia (potentially irreversible and untreatable, involuntary movements of the tongue, lips, face, trunk, and extremities). The risk is highest among elderly women, and with longer treatment durations or higher dosages. Because of this risk, the smallest effective dose of haloperidol should be used and the need for continued treatment should be reassessed periodically.
• May cause low blood pressure, sleepiness, leukopenia, neutropenia, agranulocytosis, or balance problems, increasing the risk of falls and fall-related injuries.
• May cause ECG changes and heart arrhythmias. The risk is greater with higher dosages and in people with electrolyte imbalances (particularly low potassium or low magnesium levels), concomitant medications known to prolong the QT interval, underlying cardiac abnormalities, hypothyroidism, or familial long QT syndrome.
• There is considerable individual variation in the amount of haloperidol required for treatment.
• May be associated with a detrimental effect on cognitive function and generally more side effects than other neuroleptics, such as fluphenazine and pimozide, that have also been found to be effective in the treatment of Tourette syndrome.
• The use of antipsychotics in elderly patients with dementia has been associated with an increased risk of death, mostly due to cardiovascular or infectious causes. Haloperidol injection is not FDA-approved for use in elderly patients with dementia.
• Avoid in people with Parkinson's disease, severe central nervous system depression, comatose states, or with previous hypersensitivity to haloperidol. May not be suitable for some people with certain cardiovascular disorders; receiving anticonvulsant medications or with a history of seizures; mania; or thyrotoxicosis.
• Rarely, may cause Neuroleptic Malignant Syndrome; symptoms include high body temperature, muscle rigidity, and mental disturbances. Discontinue immediately and seek urgent medical advice.
• May interact with several drugs including ketoconazole and paroxetine, those that affect the Q-T interval, or that inhibit or are metabolized by certain hepatic enzymes.
• There are no well-controlled trials on the use of haloperidol in pregnant women. However, cases of limb malformations have been reported following maternal use of haloperidol along with other drugs during the first trimester of pregnancy. Neonates exposed to haloperidol during the third trimester of pregnancy are at risk for extrapyramidal or withdrawal symptoms following delivery. Only use during pregnancy if the benefits outweigh the risks.

Note: In general, seniors or children, people with certain medical conditions (such as liver or kidney problems, heart disease, diabetes, seizures) or people who take other medications are more at risk of developing a wider range of side effects. View complete list of side effects

• Take as directed by your doctor. Haloperidol is usually dosed two to three times daily.
• Avoid alcohol while taking haloperidol as it may contribute to the side effects of haloperidol including low blood pressure.
• Haloperidol may affect your judgment and impair your ability to drive or operate machinery. It may also increase your risk of falls.
• A 'one-dose fits all' dosage schedule does not apply to haloperidol. Your doctor may have to adjust your haloperidol frequently on initiation to find the right dose for you.
• Tell your doctor if you experience any unexplained fever, muscle rigidity or unusual muscle movements, agitation, irritability, anxiety, or other uncharacteristic mental disturbances while taking haloperidol.
• Do not take any other medications either on prescription or over-the-counter without talking with a doctor or pharmacist to check that they don't interact with haloperidol.
• Do not abruptly stop haloperidol. If you need to discontinue haloperidol, your doctor will tell you how to taper it down.
• Ensure you use adequate contraception or are abstaining from sex to avoid pregnancy while taking haloperidol. If you inadvertently become pregnant while taking haloperidol, contact your healthcare provider immediately.

Haloperidol is absorbed quickly but it may take a few days to a few weeks for psychotic symptoms or symptoms of Tourette syndrome to abate. The maximum effects are usually seen within four to six weeks.

Medicines that interact with haloperidol may either decrease its effect, affect how long it works, increase side effects, or have less of an effect when taken with haloperidol. An interaction between two medications does not always mean that you must stop taking one of the medications; however, sometimes it does. Speak to your doctor about how drug interactions should be managed.

Common medications that may interact with haloperidol include:

• antibiotics, such as erythromycin, isoniazid, quinupristin/dalfopristin, or rifampin
• anticoagulants (blood thinners) such as apixaban, dabigatran, heparin, or warfarin
• anticholinergics, such as scopolamine
• anticonvulsants, such as carbamazepine, phenytoin, or valproic acid
• antihistamines, such as diphenhydramine
• antipsychotics, such as chlorpromazine, fluphenazine, thioridazine, risperidone, or trazodone
• anxiety treatments, such as alprazolam or clonazepam
• appetite suppressants, such as sibutramine
• bipolar disorder medications, such as lithium
• medicines that affect the heart's rhythm, such as amiodarone, dofetilide, dronedarone, pimozide, quinidine, sotalol, or procainamide.
• muscle relaxants
• pain relievers, such as codeine, hydrocodone, or oxycodone
• Parkinson's disease treatments, such as carbidopa, levodopa, or selegiline
• sleeping tablets, such as zolpidem
• tricyclic antidepressants, such as amitriptyline, nortriptyline
• Others, such as bupropion, cabergoline, methyldopa, pergolide, sibutramine, theophylline, and tramadol.

Avoid drinking alcohol while taking haloperidol.

Note that this list is not all-inclusive and includes only common medications that may interact with haloperidol. You should refer to the prescribing information for haloperidol for a complete list of interactions.