perphenazine
Brand names: Trilafon
Perphenazine is a medicine used to treat schizophrenia and control severe nausea and vomiting. It belongs to a class of drugs called typical antipsychotics.
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.
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.
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.
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.
Storage
Store perphenazine tablets at room temperature, away from light and moisture.
Side Effects (from patient reports)
Based on 2,010 FDA adverse event reports.
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
Death-Related Reports
221
Hospitalization Reports
971
Top Indication
Product Used For Unknown Indication
Gender Distribution
Age Distribution
Most Reported Adverse Reactions (FAERS)
| # | Reaction | Reports |
|---|---|---|
| 1 | DRUG INEFFECTIVE | 357 |
| 2 | TOXICITY TO VARIOUS AGENTS | 274 |
| 3 | WEIGHT INCREASED | 222 |
| 4 | AKATHISIA | 184 |
| 5 | SUICIDE ATTEMPT | 180 |
| 6 | OFF LABEL USE | 172 |
| 7 | OBSESSIVE-COMPULSIVE DISORDER | 163 |
| 8 | INCREASED APPETITE | 155 |
| 9 | EUPHORIC MOOD | 153 |
| 10 | PRODUCT USE IN UNAPPROVED INDICATION | 150 |
| 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 |
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.
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.
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amitriptyline
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aripiprazole
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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
Related Health & Safety Data
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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 2,010 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.
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