Description
Thioridazine is a prescription medication that falls into the class of first-generation phenothiazine antipsychotics.
While it’s used as a schizophrenia treatment in some patients, it’s not considered a first-choice drug and is only prescribed when at least 2 other antipsychotic treatments have failed or cannot be tolerated.
Thioridazine hydrochloride helps reduce symptoms of psychosis by affecting certain brain signalling. Compared to some older antipsychotics, thioridazine is less likely to cause movement-related side effects (such as stiffness, tremor, or restlessness).
| Fact Table |
| Formula |
Thioridazine: C21H26N2S2; thioridazine hydrochloride: C21H26N2S2·HCl |
| License |
US FDA, Health Canada; branded Mellaril/Melleril withdrawn or discontinued |
| Bioavailability |
Incomplete and variable; absolute oral bioavailability not established |
| Legal status |
Rx-only; Prescription (CA) |
| Chemical Name |
2-methylmercapto-10-[2-(N-methyl-2-piperidyl)ethyl]phenothiazine |
| Elimination half-life |
Approximately 21 to 25 hours; reported range about 5 to 27 hours |
| Dosage (Strength) |
Tablets: 10 mg, 25 mg, 50 mg, 100 mg thioridazine hydrochloride; adults usually 50 to 100 mg three times daily initially, total daily dose 200 to 800 mg in divided doses |
| Pregnancy |
Use only if potential benefit justifies fetal risk; third-trimester exposure may cause neonatal extrapyramidal or withdrawal symptoms; consult a doctor |
| Brands |
Mellaril, Melleril, Novoridazine, generic thioridazine hydrochloride |
| Protein binding |
Approximately 95% to 99% |
| PubChem CID |
Thioridazine: 5452; thioridazine hydrochloride: 66062 |
| MedlinePlus |
a682119 |
| ChEBI |
Thioridazine: 9566; thioridazine hydrochloride: 48566 |
| ATC code |
N05AC02 |
| DrugBank |
DB00679 |
| KEGG |
D00373; D00798 (thioridazine hydrochloride) |
| Routes of administration |
Oral |
Directions
You can buy thioridazine hydrochloride only with a valid prescription. This medication is available as an oral tablet in 10 mg, 25 mg, 50 mg, and 100 mg strengths.
A patient’s dose depends on individual factors such as the type and severity of their symptoms, how well the medication works for them, side effects, overall health, other medicines, and age. Due to thioridazine’s potentially serious side effects, doctors prescribe the smallest effective dose of this drug.
Adult patients typically start by taking 50 mg to 100 mg three times a day. If needed, healthcare providers may prescribe up to 800 mg daily for adults, with most people taking between 200 mg and 800 mg daily (2-4 doses).
Once symptoms have been successfully addressed, doctors reduce the dose gradually to find the lowest effective maintenance dose.
In contrast, pediatric doses are much lower and depend largely on weight. Doses start at 0.5 mg/kg/day, which are given in divided doses. The dose may be gradually increased, up to 3 mg/kg/day.
Ingredients
The active ingredient in this drug is thioridazine hydrochloride.
Cautions
Due to its risk of serious heart-rhythm problems, thioridazine hydrochloride should only be considered when other antipsychotics have failed or were not tolerated by the patient.
Regular heart monitoring during treatment is essential, especially during dose changes. Doctors do so by using a baseline ECG and potassium level to measure developments over time.
Dizziness, fainting, or palpitations require immediate medical attention during treatment with thioridazine, since dangerous heart-rhythm problems may be the cause.
Thioridazine hydrochloride is not approved for dementia-related psychosis in older adults, since there is an increased risk of death.
This medication should be taken for the shortest needed time at the lowest effective dose. Therefore, monitoring during treatment and periodic reassessments are crucial. One of the reasons is that long-term use can cause tardive dyskinesia (a disorder causing involuntary movements), which can be irreversible.
If you experience symptoms, such as high fever, severe muscle rigidity, or an altered mental status (e.g. confusion or agitation), you should seek medical help to rule out neuroleptic malignant syndrome (NMS), a rare but serious reaction.
Alcohol and certain medicines may slow down the brain and breathing (depression of the central nervous system). Since thioridazine may increase this effect, using caution is essential.
Patients with a seizure disorder, such as epilepsy, should use extra caution when taking thioridazine. Anticonvulsant treatment should be maintained throughout therapy if needed.
Vision changes, such as pigmentary retinopathy, may occur. This may affect your eyesight and night vision, making regular monitoring essential.
If you are pregnant, only start this medication if its potential benefits outweigh the risks. Unborn babies may be negatively affected in the third trimester.
This medication may put you at an increased risk of falls and injury, since it may cause sleepiness, low blood pressure on standing, and movement instability. Use caution to counteract these effects.
Contraindications
Do not use thioridazine in any of the following cases:
- You take other medicines known to prolong the QT interval.
- You have congenital long QT syndrome.
- You have a history of cardiac arrhythmias.
- You use medicines that significantly inhibit CYP2D6 metabolism of thioridazine.
- You have a known genetic reduction in CYP2D6 activity.
- You experience severe central nervous system depression.
- You are in a comatose state.
- You have extreme hypertensive or hypotensive heart disease.
Side Effects
Relatively mild thioridazine side effects include drowsiness, dry mouth, blurred vision, constipation, and nausea.
More serious and less common side effects include a prolonged QT interval and other serious heart rhythm problems, including torsades de pointes. Arrhythmias can be fatal and may lead to sudden death in some cases.
Other side effects include a severe low blood cell count (agranulocytosis), and neuroleptic malignant syndrome (NMS), a rare but serious reaction.
This list of thioridazine side effects is non-exhaustive. Contact your doctor if you notice any persistent or concerning side effects from thioridazine, or if you have any additional questions about this medication’s price, coverage, and other details.
Buy thioridazine hydrochloride today at a low price.
References
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Thioridazine hydrochloride tablet, film coated [prescribing information]. DailyMed. Updated November 11, 2025.
DailyMed
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IMPORTANT NOTE:
The above information is intended to increase awareness of health information and does not suggest treatment or diagnosis. This information is not a substitute for individual medical attention and should not be construed to indicate that use of the drug is safe, appropriate, or effective for you. See your health care professional for medical advice and treatment.
Product Code : 1846
Prescription Required
