Thioridazine — uses, dosing, side effects & the brands that sell it · pharmaranks
Thioridazine: uses, dosing, side effects & brands
Thioridazine is a phenothiazine sold in the U.S. under 2 brand and generic names, for psychotic disorders and schizophrenia. Below: what the FDA label says, every product that contains it, what the pills look like, and its recall record.
By the pharmaranks editorial team·Reviewed against the FDA (openFDA label, NDC Directory & Enforcement) sources·How we research
Key facts
Drug class
Phenothiazine
Treats
Psychotic Disorders and Schizophrenia
Available as
Suspension · Tablet
Sold as
2 products — Mellaril-S and Thioridazine Hydrochloride
From the FDA label for Thioridazine Hydrochloride (application ANDA088660). Other thioridazine products — different forms, different strengths — are dosed differently. Follow the label for the one you were prescribed.
Since thioridazine hydrochloride tablets are associated with a dose related prolongation of the QTc interval, which is a potentially life threatening event, its use should be reserved for schizophrenic patients who fail to respond adequately to treatment with other antipsychotic drugs. Dosage must be individualized and the smallest effective dosage should be determined for each patient (see INDICATIONS and WARNINGS ). Adults The usual starting dose for adult schizophrenic patients is 50 mg to 100 mg three times a day, with a gradual increment to a maximum of 800 mg daily if necessary. Once effective control of symptoms has been achieved, the dosage may be reduced gradually to determine the minimum maintenance dose. The total daily dosage ranges from 200 mg to 800 mg, divided into two to four doses. Pediatric Patients For pediatric patients with schizophrenia who are unresponsive to other agents, the recommended initial dose is 0.5 mg/kg/day given in divided doses. Dosage may be increased gradually until optimum therapeutic effect is obtained or the maximum dose of 3 mg/kg/day has been reached.
Thioridazine side effects
In the recommended dosage ranges with thioridazine hydrochloride most side effects are mild and transient. Central Nervous System Drowsiness may be encountered on occasion, especially where large doses are given early in treatment. Generally, this effect tends to subside with continued therapy or a reduction in dosage. Pseudoparkinsonism and other extrapyramidal symptoms may occur but are infrequent. Nocturnal confusion, hyperactivity, lethargy, psychotic reactions, restlessness, and headache have been reported but are extremely rare. Autonomic Nervous System Dryness of mouth, blurred vision, constipation, nausea, vomiting, diarrhea, nasal stuffiness, and pallor have been seen. Endocrine System Galactorrhea, breast engorgement, amenorrhea, inhibition of ejaculation, and peripheral edema have been described. Skin Dermatitis and skin eruptions of the urticarial type have been observed infrequently. Photosensitivity is extremely rare. Cardiovascular System Thioridazine produces a dose related prolongation of the QTc interval, which is associated with the ability to cause Torsades de pointes type arrhythmias, a potentially fatal polymorphic ventricular tachycardia, and sudden death (see WARNINGS ). Both Torsades de pointes type arrhythmias and sudden death have been reported in association with thioridazine. A causal relationship between these events and thioridazine therapy has…
Every thioridazine product we track (2)
Same active ingredient — different manufacturer, form, price and FDA recall record. That last one is what our independent score measures.
Imprint codes, colour and shape from the FDA’s labelling data. Match the imprint on your pill — or search any imprint.
Thioridazine pill imprints
Imprint
Strength
Colour
Shape
Maker
M;59;50
50 mg
orange
round
—
M;61;100
100 mg
orange
round
—
M;54;10
10 mg
orange
round
—
M;58;25
25 mg
orange
round
—
M;59;50
50 mg
orange
round
—
M;61;100
100 mg
Frequently asked questions
What is thioridazine?
Thioridazine hydrochloride is 2-methylmercapto-10-[2-(N-methyl-2-piperidyl) ethyl] phenothiazine. Its structural formula, molecular weight and molecular formula are: Thioridazine hydrochloride, USP is available as tablets for oral administration containing 10 mg, 25 mg, 50 mg or 100 mg. Each tablet for oral administration contains the following inactive ingredients: colloidal silicon dioxide, croscarmellose sodium, FD&C Yellow No. 6 Aluminum Lake, hydroxypropyl cellulose, hypromellose, magnesium stearate, microcrystalline cellulose, polyethylene glycol, sodium lauryl sulfate and titanium dioxide. Thioridazine Hydrochloride Structural Formula
What kind of drug is thioridazine?
The FDA classifies thioridazine as a phenothiazine. If you are checking whether it is safe to combine with something else, the class is what matters — two drugs from the same class usually should not be stacked.
Can you take thioridazine with other medicines?
It depends on the medicine. We check it against the FDA labels rather than guessing: our interaction checker searches each drug's own label for the other and quotes what it says, naming the section it came from. Run thioridazine against whatever else you take — and remember that a label not naming a drug is not the same as that combination being safe.
What brand names is thioridazine sold under?
We track 2 thioridazine-containing products in the U.S.: Mellaril-S and Thioridazine Hydrochloride. They are the same active ingredient; they differ in form, manufacturer, price and FDA recall record.
What forms does thioridazine come in?
Across the brands we track, thioridazine is currently marketed as suspension and tablet, per the FDA's National Drug Code Directory. Each form is dosed differently — follow the label for the exact product you were prescribed.
Is there a generic thioridazine?
Sources: FDA openFDA drug label, National Drug Code Directory, and Enforcement (recall) database. This page reproduces public FDA data and is not medical advice. Dosing is set by your prescriber.
Who shouldn’t take thioridazine
Thioridazine hydrochloride tablet use should be avoided in combination with other drugs that are known to prolong the QTc interval and in patients with congenital long QT syndrome or a history of cardiac arrhythmias. Reduced cytochrome P450 2D6 isozyme activity drugs that inhibit this isozyme (e.g., fluoxetine and paroxetine) and certain other drugs (e.g., fluvoxamine, propranolol, and pindolol) appear to appreciably inhibit the metabolism of thioridazine. The resulting elevated levels of thioridazine would be expected to augment the prolongation of the QTc interval associated with thioridazine and may increase the risk of serious, potentially fatal, cardiac arrhythmias, such as Torsades de pointes type arrhythmias. Such an increased risk may result also from the additive effect of coadministering thioridazine with other agents that prolong the QTc interval. Therefore, thioridazine is contraindicated with these drugs as well as in patients, comprising about 7% of the normal population, who are known to have a genetic defect leading to reduced levels of activity of P450 2D6 (see WARNINGS and PRECAUTIONS ). In common with other phenothiazines, thioridazine is contraindicated in severe central nervous system depression or comatose states from any cause including drug induced central nervous system depression (see WARNINGS ). It should also be noted that hypertensive or…
Thioridazine drug interactions
Reduced cytochrome P450 2D6 isozyme activity, drugs which inhibit this isozyme (e.g., fluoxetine and paroxetine), and certain other drugs (e.g., fluvoxamine, propranolol, and pindolol) appear to appreciably inhibit the metabolism of thioridazine. The resulting elevated levels of thioridazine would be expected to augment the prolongation of the QTc interval associated with thioridazine and may increase the risk of serious, potentially fatal, cardiac arrhythmias, such as Torsades de pointes type arrhythmias. Such an increased risk may result also from the additive effect of coadministering thioridazine with other agents that prolong the QTc interval. Therefore, thioridazine is contraindicated with these drugs as well as in patients, comprising about 7% of the normal population, who are known to have a genetic defect leading to reduced levels of activity of P450 2D6 (see WARNINGS and CONTRAINDICATIONS ). Drugs That Inhibit Cytochrome P450 2D6 In a study of 19 healthy male subjects, which included 6 slow and 13 rapid hydroxylators of debrisoquin, a single 25 mg oral dose of thioridazine produced a 2.4-fold higher C max and a 4.5-fold higher AUC for thioridazine in the slow hydroxylators compared to rapid hydroxylators. The rate of debrisoquin hydroxylation is felt to depend on the level of cytochrome P450 2D6 isozyme activity. Thus, this study suggests that drugs…
Yes. Our catalog lists 1 generic thioridazine product alongside the brand versions. A generic has the same active ingredient and must meet the FDA's bioequivalence standard; it usually costs less. Ask your pharmacist which one your plan covers.