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Thioridazine Side Effects

In Summary

More frequently reported side effects include: syncope, akathisia, constipation, dizziness, drowsiness, epithelial keratopathy, increased serum prolactin, nasal congestion, retinitis pigmentosa, sedation, star-shaped cataract, urinary retention, visual disturbance, hypohidrosis, and xerostomia. See below for a comprehensive list of adverse effects.

For the Consumer

Applies to thioridazine: tablets

Other dosage forms:

Check with your doctor if any of these most COMMON side effects persist or become bothersome:

Agitation; constipation; diarrhea; dizziness; drowsiness; dry mouth; enlarged pupils; jitteriness; nausea; stuffy nose; vomiting.

Seek medical attention right away if any of these SEVERE side effects occur while taking thioridazine:

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest or throat; swelling of the mouth, face, lips, or tongue; unusual hoarseness; wheezing); chest pain; confusion; decreased coordination; drooling; fainting; fast, slow, or irregular heartbeat; mask-like face; muscle spasms of the face, neck, or back; muscle weakness; new or worsening mental or mood problems; numbness of an arm or leg; prolonged or painful erection; restlessness; seizures; severe or persistent constipation; severe or persistent dizziness, drowsiness, or headache; shuffling walk; sleeplessness; stiff or rigid muscles; sudden shortness of breath or vomiting; swelling of the hands, ankles, or feet; symptoms of infection (eg, fever, chills, persistent sore throat); symptoms of liver problems (eg, yellowing of the skin or eyes; dark urine; pale stools; severe or persistent nausea, stomach pain, or loss of appetite); tremor; trouble urinating; twisting or twitching movements; uncontrolled muscle movements (eg, twitching of the face or tongue; loss of balance; uncontrolled movements of arms or legs; trouble speaking, breathing, or swallowing); unusual bruising or bleeding; unusual eye movements or inability to move eyes; unusual or excessive sweating; unusual tiredness or weakness; unusually pale skin; vision changes (eg, blurred vision).

For Healthcare Professionals

Applies to thioridazine: oral concentrate, oral suspension, oral tablet

Nervous system

Drowsiness has been reported to subside with continuation of therapy or a reduction in dosage.[Ref]

Frequency not reported: Lethargy, drowsiness, pseudoparkinsonism, extrapyramidal symptoms, headache, hyperactivity, akathisia, motor restlessness, dystonic reactions, opisthotonos, tremor, akinesia, tardive dyskinesia, neuroleptic malignant syndrome[Ref]


Frequency not reported: Pallor, peripheral edema, edema, dose-related QT prolongation, Torsades de pointes, arrhythmia, polymorphic ventricular tachycardia/fatal polymorphic ventricular tachycardia, hypotension, cardiac arrest, ECG changes, bifid T/U wave, depression and inversion of the T wave[Ref]

ECG changes are predicted to be reversible and are likely due to altered repolarization.[Ref]


Frequency not reported: Restlessness, nocturnal confusion, psychotic reactions, agitation, altered libido, excitement, bizarre dreams, aggravation of psychoses, toxic confusional states[Ref]


Frequency not reported: Dermatitis, urticarial skin eruptions, urticaria, photosensitivity, erythema, exfoliative dermatitis, contact dermatitis, angioneurotic edema, progressive skin pigmentation[Ref]


Frequency not reported: Dry mouth, constipation, nausea, vomiting, diarrhea, parotid swelling, obstipation, paralytic ileus[Ref]


Frequency not reported: Galactorrhea, breast engorgement, lactation, menstrual abnormalities/amenorrhea, urinary retention, urinary incontinence, inhibition of ejaculation
Postmarketing reports: Priapism[Ref]


Frequency not reported: Agranulocytosis, leukopenia, eosinophilia, thrombocytopenia, anemia, aplastic anemia, pancytopenia[Ref]


Frequency not reported: Blurred vision, miosis, oculogyric crises, progressive conjunctival pigmentation, discoloration of exposed sclera and cornea, stellate/irregular-shaped opacities of anterior lens and cornea[Ref]


Frequency not reported: Sudden death, fever, hyperpyrexia, skin-eye syndrome[Ref]


Frequency not reported: Trismus, torticollis, muscular rigidity, systemic lupus erythematosus-like syndrome[Ref]


Frequency not reported: Nasal stuffiness, laryngeal edema, asthma[Ref]


Frequency not reported: Jaundice, biliary stasis[Ref]


Frequency not reported: Gynecomastia, false positive pregnancy tests[Ref]


Frequency not reported: Anorexia, weight gain[Ref]


1. "Product Information. Mellaril (thioridazine)." Sandoz Pharmaceuticals Corporation, East Hanover, NJ.

It is possible that some side effects of thioridazine may not have been reported. These can be reported to the FDA here. Always consult a healthcare professional for medical advice.

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.