This medication is used to treat a certain mental/mood disorder (schizophrenia). Haloperidol decanoate is a long-acting form of haloperidol. It may be used by people who have trouble remembering to take medication every day. Haloperidol belongs to a class of drugs known as antipsychotics. It works by helping to restore the balance of certain natural substances in the brain.

This section contains uses of this drug that are not listed in the approved professional labeling for the drug but that may be prescribed by your health care professional. Use this drug for a condition that is listed in this section only if it has been so prescribed by your health care professional.

This drug may also be used for severe behavior problems in hyperactive children when other treatments or medications have not worked.

This medication is the long-acting form of haloperidol. It is usually used in people who have taken the form of haloperidol that is taken by mouth. It is injected deep into a muscle (usually the buttocks) by a healthcare professional. Your first dose may be divided and given as separate injections, 3 to 7 days apart. After your doctor has found the best dose for you, this medication is usually given once every 3 to 4 weeks. The dosage is based on your condition and response to treatment.

This medication takes a while to start working, so you will need to continue to take your other medication by mouth until your doctor tells you to stop.

This medication must be used as prescribed. Do not suddenly stop using this drug without consulting your doctor. Some conditions may worsen if the medication is suddenly stopped.

Tell your doctor if your symptoms do not get better or if they get worse.

Dizziness, lightheadedness, drowsiness, difficulty urinating, trouble sleeping, headache, anxiety, or pain at the injection site may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.

Dizziness and lightheadedness can increase the risk of falling. Get up slowly when rising from a sitting or lying position.

Tell your doctor right away if any of these side effects occur: muscle spasm/stiffness, shaking (tremor), restlessness, mask-like expression of the face, drooling/trouble swallowing, or shuffling walk. Your doctor may prescribe another medication to decrease these side effects.

Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

This medication may rarely cause a condition known as tardive dyskinesia. In some cases, this condition may be permanent. Tell your doctor right away if you develop any facial/muscle twitching such as tongue thrusting, chewing movements, puffing or puckering of your mouth, or uncontrollable shaking.

Tell your doctor right away if you have any serious side effects, including:

• nausea/vomiting that doesn't stop
• stomach/abdominal pain
• yellowing of eyes/skin
• seizures
• signs of infection (such as sore throat that doesn't go away, fever)

Get medical help right away if you have any very serious side effects, including:

• slow heartbeat
• severe dizziness
• chest pain
• fainting

This medication may rarely cause a very serious condition called neuroleptic malignant syndrome (NMS). Get medical help right away if you have any of the following symptoms:

• fever
• muscle stiffness/pain/tenderness/weakness
• severe tiredness
• severe confusion
• sweating
• fast/irregular heartbeat
• dark urine
• signs of kidney problems (such as change in the amount of urine)

In rare cases, haloperidol may increase your level of a certain chemical made by the body (prolactin). For females, this increase in prolactin may result in unwanted breast milk, missed/stopped periods, or difficulty becoming pregnant. For males, it may result in decreased sexual ability, inability to produce sperm, or enlarged breasts. If you develop any of these symptoms, tell your doctor right away.

Rarely, males may have a painful or prolonged erection lasting 4 or more hours. If this occurs, stop using this drug and get medical help right away, or permanent problems could occur.

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including:

• rash
• itching/swelling (especially of the face/tongue/throat)
• severe dizziness
• trouble breathing

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Before using haloperidol, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients (such as sesame oil), which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of:

• a certain severe nervous system problem (severe CNS depression)
• Parkinson's disease
• bipolar disorder
• difficulty urinating (such as due to prostate problems)
• glaucoma
• heart problems (such as angina)
• overactive thyroid (hyperthyroidism)
• seizures
• low white blood cell count

Haloperidol decanoate may cause a condition that affects the heart rhythm (QT prolongation). QT prolongation can rarely cause serious (rarely fatal) fast/irregular heartbeat and other symptoms (such as severe dizziness, fainting) that need medical attention right away.

The risk of QT prolongation may be increased if you have certain medical conditions or are taking other drugs that may cause QT prolongation. Before using haloperidol decanoate, tell your doctor or pharmacist of all the drugs you take and if you have any of the following conditions:

• certain heart problems (heart failure, slow heartbeat, QT prolongation in the EKG)
• family history of certain heart problems (QT prolongation in the EKG, sudden cardiac death)

Low levels of potassium or magnesium in the blood may also increase your risk of QT prolongation. This risk may increase if you use certain drugs (such as diuretics/"water pills") or if you have conditions such as severe sweating, diarrhea, or vomiting. Talk to your doctor about using haloperidol decanoate safely.

This drug may make you dizzy or drowsy. Alcohol or marijuana (cannabis) can make you more dizzy or drowsy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

This medication may make you sweat less, making you more likely to get heat stroke. Avoid doing things that may cause you to overheat, such as hard work or exercise in hot weather, or using hot tubs. When the weather is hot, drink a lot of fluids and dress lightly. If you overheat, quickly look for a place to cool down and rest. Get medical help right away if you have a fever that does not go away, mental/mood changes, headache, or dizziness.

Children may be more sensitive to the side effects of this drug, especially uncontrolled movements.

Older adults may be more sensitive to the side effects of this drug, especially drowsiness, dizziness, lightheadedness, difficulty urinating, and heart effects such as QT prolongation (see above). Drowsiness, dizziness, and lightheadedness can increase the risk of falling.

During pregnancy, this medication should be used only when clearly needed. Babies born to mothers who have used this drug during the last 3 months of pregnancy may rarely develop symptoms including muscle stiffness or shakiness, drowsiness, feeding/breathing difficulties, or constant crying. If you notice any of these symptoms in your newborn especially during their first month, tell the doctor right away.

Since untreated mental/mood problems (such as schizophrenia) can be a serious condition, do not stop taking this medication unless directed by your doctor. If you are planning pregnancy, become pregnant, or think you may be pregnant, immediately discuss with your doctor the benefits and risks of using this medication during pregnancy.

This drug passes into breast milk and could have undesirable effects on a nursing infant. Consult your doctor before breastfeeding.

Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

Some products that may interact with this drug include:

• cabergoline
• ketoconazole
• lithium
• methyldopa
• paroxetine
• pergolide

Many drugs besides haloperidol decanoate may affect the heart rhythm (QT prolongation), including amiodarone, dofetilide, pimozide, quinidine, sotalol, procainamide, and macrolide antibiotics (such as erythromycin), among others. Before using haloperidol, report all medications you are currently using to your doctor or pharmacist.

Tell your doctor or pharmacist if you are taking other products that cause drowsiness such as opioid pain or cough relievers (such as codeine, hydrocodone), alcohol, marijuana (cannabis), drugs for sleep or anxiety (such as alprazolam, lorazepam, zolpidem), muscle relaxants (such as carisoprodol, cyclobenzaprine), or antihistamines (such as cetirizine, diphenhydramine).

Check the labels on all your medicines (such as allergy or cough-and-cold products) because they may contain ingredients that cause drowsiness. Ask your pharmacist about using those products safely.

If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call 1-800-222-1222. Canada residents can call 1-844-764-7669.

Not applicable.

If you miss an appointment, call your doctor as soon as possible to set up an appointment. It is important that you stay on schedule with this medication.

Not applicable. This medication is given in a doctor's office and will not be stored at home.