Thioridazine Side Effects
More frequently reported side effects include: syncope, akathisia, constipation, dizziness, drowsiness, epithelial keratopathy, increased serum prolactin, nasal congestion, retinitis pigmentosa, sedated state, 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: oral tablet
You should not use thioridazine if you have a heart rhythm disorder, a history of long QT syndrome, untreated or uncontrolled high blood pressure, very low blood pressure, or if you have drowsiness, slow breathing, weak pulse, or decreased alertness.
Thioridazine is not approved for use in older adults with dementia-related psychosis.
Thioridazine can cause a serious heart problem, especially if you also use certain other medicines for infections, asthma, heart problems, high blood pressure, depression, mental illness, cancer, malaria, or HIV. Tell your doctor about all your current medicines and any you start or stop using.
Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
High doses or long-term use of thioridazine can cause a serious movement disorder that may not be reversible. The longer you use thioridazine, the more likely you are to develop this disorder, especially if you are a woman or an older adult.
Call your doctor at once if you have:
uncontrolled muscle movements in your arms, legs, or face (chewing, lip smacking, frowning, tongue movement, blinking or eye movement);
fast or pounding heartbeats, fluttering in your chest, shortness of breath, and sudden dizziness (like you might pass out);
decreased night vision, tunnel vision, watery eyes, increased sensitivity to light;
little or no urinating;
low white blood cell counts--fever, chills, mouth sores, skin sores, sore throat, cough, trouble breathing, feeling light-headed; or
severe nervous system reaction--very stiff (rigid) muscles, high fever, sweating, confusion, fast or uneven heartbeats, tremors, feeling like you might pass out.
Common side effects may include:
dry mouth, blurred vision;
breast swelling or discharge;
changes in your menstrual periods; or
swelling in your hands or feet.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects.
For Healthcare Professionals
Applies to thioridazine: oral concentrate, oral suspension, oral tablet
Frequency not reported: Akathisia, akinesia, autonomic instability, drowsiness, dystonic reactions, extrapyramidal symptoms, headache, hyperactivity, lethargy, motor restlessness, neuroleptic malignant syndrome, opisthotonos, parkinsonism, pseudoparkinsonism, tardive dyskinesia, tremor[Ref]
Drowsiness has been reported to subside with continuation of therapy or a reduction in dosage.[Ref]
Frequency not reported: Arrhythmia, bifid T/U wave, cardiac arrest, cardiac dysrhythmias, depression and inversion of the T wave, dose-related QT prolongation, ECG changes, edema, hypotension, irregular blood pressure, irregular pulse, pallor,
ECG changes are predicted to be reversible and are likely due to altered repolarization.[Ref]
Frequency not reported: Aggravation of psychoses, agitation, altered libido, altered mental status, behavioral effects, bizarre dreams, excitement, nocturnal confusion, psychotic reactions, restlessness, toxic confusional states[Ref]
Frequency not reported: Blurred vision, discoloration of exposed sclera and cornea, miosis, oculogyric crises, progressive conjunctival pigmentation, stellate/irregular-shaped opacities of anterior lens and cornea[Ref]
Frequency not reported: Fever, hyperpyrexia, paradoxical reaction, skin-eye syndrome, sudden death[Ref]
Frequency not reported: Asthma, laryngeal edema, nasal stuffiness[Ref]
Frequency not reported: False positive pregnancy tests, gynecomastia[Ref]
Frequency not reported: Anorexia, weight gain[Ref]
More about thioridazine
- Drug interactions
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- During pregnancy or Breastfeeding
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- Drug class: phenothiazine antipsychotics
Related treatment guides
1. "Product Information. Mellaril (thioridazine)." Sandoz Pharmaceuticals Corporation (2001):
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
Some side effects may not be reported. You may report them to the FDA.