Prescription medication · Typical Antipsychotic (Phenothiazine)
perphenazine
Also sold as Trilafon. Perphenazine is used to treat schizophrenia in adults.
Data updated 2026-05-15
- 2,013
- FDA reportsRarely reported
- 5
- InteractionsFew interactions
- $0.40
- Generic price (NADAC)
What the data shows
perphenazine (Trilafon) is a prescription Typical Antipsychotic (Phenothiazine), among the least-reported drugs the FDA tracks (2,013 FDA reports), with 5 documented drug interactions.
Reporting volume reflects how widely a drug is used and studied, not how dangerous it is, a FAERS report documents a temporal association, never proof of cause.
perphenazine (Trilafon) is a prescription Typical Antipsychotic (Phenothiazine). Perphenazine is used to treat schizophrenia in adults.
Perphenazine is a medicine used to treat schizophrenia and control severe nausea and vomiting. It belongs to a class of drugs called typical antipsychotics.
Verify with FDA → · CMS NADAC pricing →
Drug Pricing (NADAC)
Generic Price
$0.40/unit
Generic Available
Yes (9 manufacturers)
Pricing data from NADAC (CMS), effective December 18, 2024. Compare all drug costs →
What it does
Perphenazine is used to treat schizophrenia in adults.
Common side effects
Muscle stiffness or spasms, Restlessness, Slow movements
Key warnings
This medicine may increase the risk of death in elderly patients with dementia-related psychosis.
The sections below are summarized in plain English from perphenazine's FDA-approved prescribing information. They describe what the official label says, and are not personal medical advice.
How It Works
Perphenazine works by changing the levels of certain natural chemicals in the brain. These chemicals, called neurotransmitters, help to regulate mood and behavior. By affecting these chemicals, perphenazine can help reduce symptoms of schizophrenia and control nausea.
How to Take It
Take perphenazine exactly as your doctor tells you. The dose will be based on your condition and how you respond to the medicine. For schizophrenia, you may take it 2 to 4 times a day. Your doctor may adjust your dose over time to find what works best for you.
This is a plain-language summary of perphenazine's FDA labeling, not individualized dosing advice. Ask a pharmacist or prescriber before changing how you take this medication.
Pregnancy & Breastfeeding
Tell your doctor if you are pregnant or plan to become pregnant. It is not known if perphenazine will harm an unborn baby. Talk to your doctor about the risks and benefits of taking this medicine while pregnant or breastfeeding.
This is a plain-language summary of perphenazine's FDA labeling, not individualized advice. Ask a pharmacist or prescriber about pregnancy or breastfeeding on this medication.
Missed Dose
If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and continue with your regular schedule.
This is a plain-language summary of perphenazine's FDA labeling, not individualized advice. Ask a pharmacist or prescriber what to do about your specific missed dose.
Storage
Store perphenazine tablets at room temperature, away from light and moisture.
Side Effects (from patient reports)
Based on 2,013 FDA adverse event reports.
Most-reported reactions
Adverse reactions in FAERS for perphenazine, by number of reports
- Harmful reaction to substances
Harmful reaction to substances
274 reports
- Weight gain
Weight gain
222 reports
- Restlessness
Restlessness
184 reports
- Attempt to end one's life
Attempt to end one's life
180 reports
- Condition causing repetitive thoughts and behaviors
Condition causing repetitive thoughts and behaviors
163 reports
- Feeling more hungry
Feeling more hungry
155 reports
- Feeling very happy
Feeling very happy
153 reports
- Not enough medicine in the blood to work
Not enough medicine in the blood to work
149 reports
- Acting without thinking
Acting without thinking
148 reports
- Medicine not fully effective
Medicine not fully effective
142 reports
What this shows Bars show how often each reaction was reported, not how likely it is to happen, a report records a temporal association, never proof that the drug caused it.
Reports over time
Adverse-event reports filed for perphenazine each year to the FDA Adverse Event Reporting System (FAERS).
Year-to-year volume tracks usage, prescribing, and scrutiny, not a change in per-patient risk. Source: FDA FAERS.
Where perphenazine sits
perphenazine has more FDA adverse-event reports than 13% of the drugs FAERS tracks. A high position reflects how widely a drug is used and watched, not how dangerous it is.
Percentile across all drugs PlainMeds tracks by FAERS report volume. The dot is perphenazine; the line is the median (50th percentile).
FDA Adverse Event Report Analysis
Detailed analysis of 2,013 reports from the FDA Adverse Event Reporting System (FAERS). Reports span 2004–2025.
Total Reports
2,013
Reports Mentioning Death
221
11.0% of reports — not proof of cause
Hospitalization Reports
971
Top Indication
Product Used For Unknown Indication
Gender Distribution
Age Distribution
Most Reported Adverse Reactions (FAERS)
| # | Reaction | Reports |
|---|---|---|
| 2 | TOXICITY TO VARIOUS AGENTS | 274 |
| 3 | WEIGHT INCREASED | 222 |
| 4 | AKATHISIA | 184 |
| 5 | SUICIDE ATTEMPT | 180 |
| 7 | OBSESSIVE-COMPULSIVE DISORDER | 163 |
| 8 | INCREASED APPETITE | 155 |
| 9 | EUPHORIC MOOD | 153 |
| 11 | ANTIPSYCHOTIC DRUG LEVEL BELOW THERAPEUTIC | 149 |
| 12 | DISINHIBITION | 148 |
| 13 | THERAPEUTIC PRODUCT EFFECT INCOMPLETE | 142 |
| 14 | THERAPEUTIC PRODUCT EFFECT VARIABLE | 140 |
| 15 | LEUKOPENIA | 139 |
| 16 | DRUG INTERACTION | 125 |
| 17 | HYPERTENSION | 117 |
| 18 | FATIGUE | 106 |
Reactions in Death Reports
Reactions in Hospitalization Reports
Source: FDA FAERS (Adverse Event Reporting System) FDA FAERS (Adverse Event Reporting System) Reports are voluntary and do not establish causation
Serious Warnings
This medicine may increase the risk of death in elderly patients with dementia-related psychosis. Perphenazine is not approved to treat dementia-related psychosis. Talk to your doctor about the risks if you are an older adult with dementia.
Known Drug Interactions
Among these are tricyclic antidepressants and selective serotonin reuptake inhibitors, e.g., fluoxetine, sertraline and paroxetine.
Mechanism: Sertraline can slow down how your body breaks down perphenazine, which could lead to higher levels of the drug in your system.
What to do: Your doctor should watch for increased side effects and may need to adjust your perphenazine dose.
Among these are tricyclic antidepressants and selective serotonin reuptake inhibitors, e.g., fluoxetine, sertraline and paroxetine.
Mechanism: Fluoxetine can interfere with the way your body processes perphenazine, potentially causing the medication to build up in your body.
What to do: Your healthcare provider may need to lower your dose of perphenazine or monitor you more closely for side effects.
perphenazine, risperidone, thioridazine ↑ antipsychotics A decrease in the dose of antipsychotics that are metabolized by CYP3A or CYP2D6 may be needed when co-administered with darunavir/ritonavir.
Mechanism: Darunavir stops the body from breaking down perphenazine normally, which can cause the drug to build up to higher levels.
What to do: Your doctor may need to lower your dose of perphenazine to avoid potential side effects.
Examples desipramine, atomoxetine, dextromethorphan, metoprolol, nebivolol, perphenazine, tolterodine 7.2 Drugs Having No Clinically Important Interactions with PRISTIQ Based on pharmacokinetic studies, no dosage adjustment is required for drugs that are mainly metabolized by CYP3A4 (e.g., midazolam), or for drugs that are metabolized by both CYP2D6 and CYP3A4 (e.g., tamoxifen, aripiprazole), when administered concomitantly with PRISTIQ [see Clinical Pharmacology (12.3) ].
Mechanism: This combination can affect how your liver clears perphenazine from your body, which might slightly increase the risk of side effects.
What to do: You should continue your medication as prescribed and report any new symptoms to your healthcare provider.
Examples propafenone, flecainide, atomoxetine, desipramine, dextromethorphan, metoprolol, nebivolol, perphenazine, tolterodine, venlafaxine, risperidone.
Mechanism: Paroxetine slows down the process that clears perphenazine from your system. This leads to higher amounts of the medication in your body than intended.
What to do: Talk to your doctor about adjusting your perphenazine dose to avoid unwanted side effects.
This is a plain-language summary of interactions documented in FDA labeling, not individualized advice. Ask a pharmacist or prescriber before combining medications.
Common Questions
Can I drink alcohol while taking perphenazine?
How long does it take for perphenazine to start working?
Can I stop taking perphenazine suddenly?
Will perphenazine interact with other medications I'm taking?
Can perphenazine cause weight gain?
What should I do if I experience muscle stiffness or spasms?
Can perphenazine cause drowsiness?
Is it safe to take perphenazine if I have liver problems?
What are the symptoms of tardive dyskinesia?
Can perphenazine cause changes in my heart rhythm?
What are the common side effects of perphenazine?
Does perphenazine interact with other medications?
What drug class is perphenazine?
Is perphenazine safe during pregnancy?
Related Medications in Typical Antipsychotic (Phenothiazine)
Other drugs grouped near perphenazine - same-class peers and common alternatives.
acamprosate
Campral
Acamprosate is a medicine that can help you stay away from alcohol if you are alcohol-dependent and have already stopped drinking.
Compare with perphenazine →
alprazolam
Xanax
Alprazolam (Xanax) is a medication that can help you with anxiety and panic disorders.
Compare with perphenazine →
amitriptyline
Elavil
Amitriptyline is a medicine used to treat depression.
Compare with perphenazine →
amphetamine/dextroamphetamine
Adderall, Adderall XR
Adderall XR is a stimulant medicine.
Compare with perphenazine →
aripiprazole
Abilify
Aripiprazole (Abilify) is a medicine used to treat certain mental disorders and mood problems.
Compare with perphenazine →
Medication Guides
Understanding Drug Interactions
How CYP450 enzymes, inhibitors, and inducers affect your medications
Generic vs Brand Name Drugs
FDA requirements, cost savings, and when the difference matters
Narrow Therapeutic Index Drugs
Why some drugs demand precise dosing and monitoring
Common Drug Interactions
Dangerous medication combinations and how to protect yourself
Save on perphenazine
Compare prices and find discounts at pharmacies near you. Free coupons can save up to 80% on prescriptions.
Disclosure: This link may earn us a commission at no extra cost to you. See our terms.
What the FDA Data Shows for perphenazine
The FDA label for perphenazine (sold under brand names such as Trilafon) classifies it as a prescription-only medication in the Typical Antipsychotic (Phenothiazine) class. Perphenazine is used to treat schizophrenia in adults. Official labeling lists 8 commonly reported side effects, including Muscle stiffness or spasms, Restlessness, Slow movements.
Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. For this drug, FAERS contains 2,013 voluntary reports. The database also lists 5 documented drug interactions derived from FDA labeling, with the top-flagged interaction rated minor severity. NADAC pricing from CMS shows a generic unit cost of $0.40.
Report counts do not establish causation, a FAERS entry documents a temporal association, not proof that the drug produced the outcome. Widely prescribed medications naturally accumulate more reports than niche therapies, so raw totals must be interpreted alongside total exposure. Shortage status, recall history, and patent information further shape supply and switching decisions. This page summarizes public FDA data for educational purposes only and is not a substitute for professional medical advice, always consult a licensed healthcare provider before starting, stopping, or changing any medication.
Data Sources
Drug labeling: FDA Drug Labels (SPL/DailyMed). Adverse events: FDA Adverse Event Reporting System (FAERS). Pricing: CMS National Average Drug Acquisition Cost (NADAC).
FAERS reports are voluntary and do not establish causation. Drug interactions are derived from FDA labeling and clinical references. Always consult a healthcare professional before making medication decisions.
Last updated: November 14, 2024
Read our methodology - how this data is sourced, computed, and verified.
Data currency: FDA FAERS adverse-event reports through 2025, CMS NADAC acquisition-cost pricing effective December 2024, compiled and last refreshed May 2026. See our methodology for per-source dates and refresh cadence. Spot a figure that looks wrong? Report a correction.
All federal data sources used on this page
- FDA Orange Book - approved drug products with therapeutic equivalence. accessdata.fda.gov/cder/ob
- FDA DailyMed - NIH-hosted drug labeling for FDA-approved meds. dailymed.nlm.nih.gov
- FDA Adverse Event Reporting System (FAERS) - post-marketing safety surveillance. fda.gov/drugs/faers
- NLM RxNorm - standardized clinical drug nomenclature. nlm.nih.gov/research/umls/rxnorm
- CMS Medicare Part B Drug Average Sales Price Files - federal drug pricing data. cms.gov/medicare/part-b-drugs/asp
- FDA Drug Shortages Database - current and resolved drug shortage tracking. accessdata.fda.gov/drugshortages