thioridazine
Brand names: Mellaril
Thioridazine is a medicine used to treat schizophrenia. It is only used when other antipsychotic medicines have not worked well enough.
Drug Pricing (NADAC)
Generic Price
$0.45/unit
Generic Available
Yes (6 manufacturers)
Pricing data from NADAC (CMS), effective December 18, 2024. Compare all drug costs →
What it does
Thioridazine is used to manage schizophrenia in adults and children.
Common side effects
Drowsiness, Dry mouth, Blurred vision
Key warnings
Thioridazine can cause a life-threatening heart rhythm problem called Torsades de pointes, which can lead to sudden death.
How It Works
Thioridazine affects the balance of certain chemicals in the brain. These chemicals, like dopamine, can affect mood and behavior. By changing the balance, thioridazine helps to reduce symptoms of schizophrenia.
How to Take It
Take thioridazine exactly as your doctor tells you. Adults usually start with 50 mg to 100 mg three times a day. Your doctor may slowly increase the dose up to 800 mg per day if needed. You can take this medicine with or without food.
Pregnancy & Breastfeeding
Tell your doctor if you are pregnant or plan to become pregnant. It is not known if thioridazine will harm your unborn baby. Talk to your doctor about the risks and benefits of taking thioridazine during pregnancy and 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 thioridazine tablets at room temperature (68° to 77°F) and protect them from light.
Side Effects (from patient reports)
Based on 64 FDA adverse event reports.
FDA Adverse Event Report Analysis
Detailed analysis of 51 reports from the FDA Adverse Event Reporting System (FAERS). Reports span 2004–2025.
Total Reports
51
Death-Related Reports
8
Hospitalization Reports
17
Top Indication
Product Used For Unknown Indication
Gender Distribution
Age Distribution
Most Reported Adverse Reactions (FAERS)
| # | Reaction | Reports |
|---|---|---|
| 1 | WEIGHT INCREASED | 8 |
| 2 | DRUG INEFFECTIVE | 7 |
| 3 | DYSPNOEA | 7 |
| 4 | DYSTONIA | 6 |
| 5 | HYPERGLYCAEMIA | 6 |
| 6 | HYPOXIA | 6 |
| 7 | MALAISE | 6 |
| 8 | MUSCLE SPASMS | 6 |
| 9 | PRURITUS | 6 |
| 10 | PSYCHOTIC DISORDER | 6 |
| 11 | TINNITUS | 6 |
| 12 | TOXICITY TO VARIOUS AGENTS | 6 |
| 13 | ABDOMINAL DISTENSION | 5 |
| 14 | ABDOMINAL PAIN | 5 |
| 15 | AKATHISIA | 5 |
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
Thioridazine can cause a life-threatening heart rhythm problem called Torsades de pointes, which can lead to sudden death. Because of this risk, only use thioridazine if other antipsychotic medicines have not worked. Elderly patients with dementia-related psychosis who are treated with antipsychotic drugs have an increased risk of death.
Known Drug Interactions
NSAIDs, Aspirin, Warfarin): May potentiate the risk of bleeding ( 7.4 ) Drugs Tightly Bound to Plasma Proteins: May cause a shift in plasma concentrations ( 7.6 , 7.7 ) Olanzapine: When used in combination with fluoxetine, also refer to the Drug Interactions section of the package insert for Symbyax ( 7.7 ) Drugs that Prolong the QT Interval: Do not use fluoxetine with thioridazine or pimozide. Thioridazine — Thioridazine should not be administered with fluoxetine or within a minimum of 5 weeks after fluoxetine has been discontinued, because of the risk of QT Prolongation [see Contraindicat...
Mechanism: These drugs can cause serious heart rhythm problems when used at the same time. Because fluoxetine stays in your system for a long time, the danger remains even after you stop taking it.
What to do: Do not take these drugs together, and wait at least five weeks after stopping fluoxetine before starting thioridazine.
Examples selegiline, tranylcypromine, isocarboxazid, phenelzine, linezolid, methylene blue Pimozide and Thioridazine Clinical Impact Increased plasma concentrations of pimozide and thioridazine, drugs with a narrow therapeutic index, may increase the risk of QTc prolongation and ventricular arrhythmias. Intervention Paroxetine is contraindicated in patients taking pimozide or thioridazine [see Contraindications ( 4 )] .
Mechanism: Paroxetine increases the amount of thioridazine in your blood by slowing down its breakdown. This can lead to a dangerous heart condition where the heart's electrical timing is thrown off.
What to do: This combination is contraindicated and should never be used. Your healthcare provider will need to adjust your treatment plan to use safer alternatives.
Table 4: Clinically Relevant Interactions Affecting Drugs Co-Administered with VARUBI CYP2D6 Substrates Narrow Therapeutic Index Drugs (Thioridazine and Pimozide) Clinical Impact: Increased plasma concentrations of thioridazine and pimozide are associated with serious and/or life-threatening events of QT prolongation and Torsades de Pointes. Intervention: VARUBI is contraindicated in patients taking CYP2D6 substrates with a narrow therapeutic index such as thioridazine and pimozide. If patients require these drugs, use an alternative antiemetic to VARUBI or an alternative to thioridazine or...
Mechanism: Rolapitant prevents the body from processing thioridazine, causing it to build up to unsafe levels. High levels of this drug can cause life-threatening heart rhythm issues.
What to do: This combination must be avoided. Ask your doctor for a different treatment option for either your nausea or your mental health condition.
Avoid co-administration of abiraterone acetate with substrates of CYP2D6 with a narrow therapeutic index (e.g., thioridazine).
Mechanism: Abiraterone interferes with the enzyme that breaks down thioridazine. Because thioridazine has a very narrow safety range, even a small increase in its levels could lead to dangerous side effects.
What to do: Avoid taking these two medications at the same time. Your healthcare provider should look for safer alternatives.
7 DRUG INTERACTIONS Caution should be taken when darifenacin extended-release tablets are used concomitantly with medications that are predominantly metabolized by CYP2D6 and which have a narrow therapeutic window, such as flecainide, thioridazine and tricyclic antidepressants ( 7.2 ) The concomitant use of darifenacin extended-release tablets with other anticholinergic agents may increase the frequency and/or severity of dry mouth, constipation, blurred vision and other anticholinergic pharmacological effects. 7.3 CYP2D6 Substrates Caution should be taken when darifenacin extended-release ...
Mechanism: Darifenacin can slow down the way your body breaks down thioridazine. This can cause thioridazine to build up to unsafe levels in your blood, which may lead to dangerous side effects.
What to do: Use this combination with caution. Your doctor may need to adjust your dosage or monitor you more frequently for side effects.
Common Questions
Can I take thioridazine with other medicines?
What should I avoid while taking thioridazine?
How long does it take for thioridazine to work?
Can I stop taking thioridazine suddenly?
What if I feel worse after starting thioridazine?
Will thioridazine make me gain weight?
Can thioridazine cause diabetes?
Does thioridazine affect my heart?
Can I drive while taking thioridazine?
What are the symptoms of Torsades de pointes?
What are the common side effects of thioridazine?
Does thioridazine interact with other medications?
What drug class is thioridazine?
Is thioridazine safe during pregnancy?
Related Medications in Typical Antipsychotic (Phenothiazine)
Other drugs grouped near thioridazine — same-class peers and common alternatives.
acamprosate
Campral
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alprazolam
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amitriptyline
Elavil
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amphetamine/dextroamphetamine
Adderall, Adderall XR
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aripiprazole
Abilify
Aripiprazole (Abilify) is a medicine used to treat certain mental disorders and mood problems.
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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
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What the FDA Data Shows for thioridazine
The FDA label for thioridazine (sold under brand names such as Mellaril) classifies it as a prescription-only medication in the Typical Antipsychotic (Phenothiazine) class. Thioridazine is used to manage schizophrenia in adults and children. Official labeling lists 8 commonly reported side effects, including Drowsiness, Dry mouth, Blurred vision.
Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. For this drug, FAERS contains 64 voluntary reports. The database also lists 17 documented drug interactions derived from FDA labeling, with the top-flagged interaction rated major severity. NADAC pricing from CMS shows a generic unit cost of $0.45.
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 11, 2025
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