thoughtscape NP Psychiatry · Patient education
Perphenazine
Trilafon (historical brand) / perphenazine
An antipsychotic for schizophrenia. Treatment means checking benefit, movement, and other side effects together.
Draft for review · Clinical content has not been revalidated for this website.
Also used for severe adult nausea and vomiting • Not approved for dementia-related psychosis
What it is used for
Treats schizophrenia symptoms such as hallucinations and unusual beliefs. Other psychotic-disorder uses may be off-label.
It also treats severe nausea and vomiting in adults, using a different regimen. It is not a routine sleep or simple-anxiety medicine.
How it works
Blocks dopamine D2 receptors. This can reduce psychotic symptoms but also contribute to stiffness, restlessness, or hormone changes.
Other receptor actions may contribute to sleepiness and dry mouth. No diagram predicts exactly how much benefit or risk you will have.
What to expect over time
FIRST DAYS
Sleepiness, standing dizziness, or muscle symptoms may appear. Report sudden spasms or distressing restlessness promptly.
OVER SEVERAL WEEKS
Psychosis may improve gradually. Follow daily function as well as symptoms; being quieter or sleepier is not the only goal.
THROUGHOUT TREATMENT
Keep movement and physical-health checks from the start. Some involuntary movements can persist after treatment stops.
Taking your medication
Take at the prescribed times, with or without food. Doses may be divided; do not combine them into one evening dose yourself.
Rise slowly. Avoid alcohol and driving or dangerous tasks until you know how the medicine affects alertness, balance, and movement.
Do not stop suddenly or make dose changes yourself. Tell your prescriber if restlessness, stiffness, or slowing is getting worse.
When to get help
Fever with severe stiffness, confusion, or a racing pulse: do not take more; seek emergency care for a possible serious drug reaction.
Sudden neck, jaw, or eye spasms need urgent treatment. Call 911 for trouble breathing/swallowing, collapse, seizures, or immediate danger.
Get urgent care for jaundice or severe belly pain/swelling. Call promptly for fever, sore throat, new movements, or severe restlessness.
Early side effects
Drowsiness, standing dizziness, dry mouth, constipation, and blurred vision can occur. Stiffness or an urge to keep moving needs review.
Other effects to discuss
Report tremor, involuntary movements, breast changes, missed periods, or sexual problems. Weight and blood-sugar changes are still possible.
What to keep track of
Keep movement checks, including a baseline and periodic AIMS exam. Follow weight, blood pressure, blood sugar, and cholesterol early and over time. Blood counts and liver/kidney tests also matter. Heart tracing and hormone tests depend on your risks or symptoms; lower relative risk is not no risk.
Before you start
Discuss prior blood-count or liver problems, brain injury, Parkinson disease, dementia, seizures, falls, heart, or breathing disease, glaucoma, retention, and constipation. Share medicines, allergies, alcohol use, and pregnancy or breastfeeding plans. Existing blood disorders or liver damage can rule this medicine out.
Medicines & interactions
Medicines that raise levels
Fluoxetine, paroxetine, bupropion, and other enzyme blockers may increase perphenazine effects. Your prescriber may need to adjust dosing or monitoring.
Alcohol / other sedatives
Avoid alcohol. Opioids, sleep, or anxiety drugs and sedating allergy medicines add impairment; combinations require your prescriber's review.
Other movement-related medicines
Metoclopramide and other dopamine-blocking drugs can add movement problems. With lithium, report new confusion, poor balance, or marked tremor urgently.
Cold, allergy, or bladder medicines
Some worsen constipation, retention, confusion, and overheating. Ask before adding them; do not routinely self-treat movement symptoms with diphenhydramine.
Heart, blood-pressure, and other drugs
Check drugs that affect rhythm, blood pressure, or seizure risk, including tramadol. Perphenazine can oppose levodopa and other dopamine medicines.
Everyday tips
Use sun protection and avoid overheating. Plan suitable fluids, shade, and breaks in hot weather; ask before strenuous exercise in heat.
Tell your team about constipation, urinary trouble, falls or persistent vision changes. Do not assume emotional flatness only means a high dose.
Tell your doctor or dentist before surgery. Keep a medicine list and arrange refills early. Ask about secure, limited supplies if safety is a concern.
Keep all follow-ups. Older adults with dementia-related psychosis have an increased risk of death with antipsychotics; discuss this warning with the team.
Your questions, answered
What if I miss a dose?
Take it when remembered unless the next dose is near; then skip it. Never double. Ask your pharmacist if timing or several missed doses are unclear.
Can I stop when I feel better?
Plan a gradual taper with your prescriber, often over weeks or longer. Abrupt stopping may cause nausea, insomnia, new movements, or returning psychosis.
Is an older medicine less useful?
Not necessarily. Choose based on your response and side effects, not age of the medicine. Movement checks do not replace metabolic or other safety monitoring.
Pregnancy or breastfeeding?
Discuss benefits and risks rather than stopping on your own. Late-pregnancy exposure may affect newborn movement, feeding, or breathing. Nursing data are limited; monitor infant alertness and feeding.
Storage & safety
Store in the original light-protective container at room temperature, securely away from children; never share. Suspected overdose: call U.S. Poison Help 1-800-222-1222 immediately. Do not induce vomiting. Call 911 for collapse, seizure, breathing trouble, inability to wake, or imminent self-harm.
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.