thoughtscape NP Psychiatry · Patient education
Haloperidol
Haldol / Haldol Decanoate
An antipsychotic used for psychosis and other symptoms. Report movement changes early.
Draft for review · Clinical content has not been revalidated for this website.
Diagram: D2 and alpha1 effects are supported. Other tabs are qualified in the companion clinical record.
What it is used for
Haloperidol treats psychotic disorders and Tourette tics. The long-acting shot treats adult schizophrenia after stabilization on oral haloperidol.
Acute mania and some forms of severe agitation are other uses, outside the U.S. approved indications. Ask which symptoms your prescription is intended to help.
How it works
Dopamine D2 blockade can help psychosis, but also cause stiffness, tremor, restlessness, muscle spasms, and a rise in the hormone prolactin.
Dizziness on standing is possible. Weight and blood-sugar changes may be less likely than with some alternatives, but can still happen.
What to expect over time
EARLY DAYS
Agitation may settle before other symptoms. Muscle spasms or restlessness can appear early; report them rather than pushing through.
OVER WEEKS
Review thoughts, sleep, daily function, and side effects. Feeling slowed or emotionally flat deserves review, not an assumed explanation.
WITH DECANOATE
Levels build over several monthly doses. Changes can have delayed effects; keep injection visits even when you feel well.
Taking your medication
Follow your exact oral schedule; doses may be divided through the day. For liquid, have the pharmacist show how to measure the prescribed amount accurately.
A clinician gives decanoate into a muscle, usually every four weeks. It is not the same as a short-acting shot. Follow any prescribed oral-supplement plan.
Avoid alcohol and overheating; rise slowly. Do not drive until you know the effects. Do not change, stop or add movement treatment yourself.
When to get help
Emergency care: fever with severe stiffness or confusion; fainting, racing, or irregular heartbeat; seizure, severe allergy, trouble breathing, or swallowing.
Same-day care: neck or jaw spasms, eyes stuck upward, new tongue, or face movements, severe restlessness, fever, or sore throat.
Urgent help: painful erection lasting hours, severe bowel, or urinary problems, or jaundice. Self-harm emergency: 911; U.S. crisis help: 988.
Early side effects
Stiffness, tremor, restlessness, sleepiness, dizziness, dry mouth, and constipation may occur. Report falls and swallowing problems promptly.
Other effects to discuss
Report breast changes, milk discharge, missed periods, or sexual difficulties. Involuntary movements can persist after stopping; seek review early.
What to keep track of
Keep movement, weight, blood-pressure, blood-sugar, and cholesterol checks. Decanoate needs baseline ECG and electrolyte review; repeat heart checks depend on risk. Prior low white cells may need frequent blood counts. Report injection-site problems, returning symptoms, and sexual or menstrual changes; prolactin testing may be needed.
Before you start
Tell your team about Parkinson disease, Lewy body dementia, fainting, or heart-rhythm problems, low blood salts, seizures, thyroid, kidney or liver disease, low white blood cells, and medication allergies, including sesame oil in decanoate. Antipsychotics increase death risk in older adults with dementia-related psychosis; haloperidol is not approved for that use. Review every medicine before starting.
Medicines & interactions
Heart-rhythm medicines
Some antibiotics, methadone, and antipsychotics add rhythm risk. Check each combination; more ECGs and blood-salt tests may be needed.
Medicines that change its level
Fluoxetine, paroxetine, and fluvoxamine may increase exposure; carbamazepine or rifampin may reduce it. Starting or stopping another medicine can change the dose needed.
Alcohol, opioids & sedatives
Avoid alcohol. Opioids, benzodiazepines, and sleep aids add sedation. Check nonprescription allergy and sleep products too.
Lithium & Parkinson medicines
Lithium combinations need close review for confusion, weakness, or new movements. Levodopa and dopamine agonists work against haloperidol; specialist planning is needed.
Anticholinergics & supplements
Some bladder, allergy, or movement medicines add constipation, blurred vision, and confusion; they can worsen tardive dyskinesia. Check herbs, including St. John's wort, before use.
Everyday tips
Keep reminders for daily medicine and injection appointments.
Report movement changes early; treatment depends on the cause.
Tell your team about smoking changes and all new products.
Tell dentists and other clinicians that you take haloperidol.
Your questions, answered
Missed a dose or injection?
Take a missed oral dose unless the next is nearly due; then skip it. Never double. Call after a long gap or missed shot; do not restart or add tablets yourself.
Can I stop when I feel better?
Plan changes with your prescriber. Sudden stopping can bring symptoms or new movements. Shots stay active for weeks but still need a supervised stopping plan.
What if I feel stiff or emotionally flat?
Tell your team. A dose change, another medicine, or a switch may help; the response depends on the cause. Not every movement effect is fully reversible.
Pregnancy or breastfeeding?
Plan with your prescriber; do not stop yourself. Late exposure may affect newborn breathing, feeding, or movement. When nursing, report excess infant sleepiness, irritability, poor feeding, or unusual movements.
Storage & safety
Store oral medicine tightly closed at room temperature, away from heat and moisture. Protect liquid from light; do not freeze. Keep securely away from children and pets; never share. Overdose: Poison Help 1-800-222-1222. Collapse, seizure, breathing trouble, or inability to wake: 911.
About this information
For general information only; not a substitute for individualized medical advice. This sheet does not cover every risk or interaction. Ask your prescriber or pharmacist before changing how you take this medication.
Sources
Educational inclusion does not mean this medication or its indications are treated at this practice. Review the guide for your exact product with your prescriber or pharmacist.