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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: oral tablet

What are some side effects that I need to call my doctor about right away?

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

  • Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
  • Trouble controlling body movements, twitching, change in balance, trouble swallowing or speaking.
  • A heartbeat that does not feel normal.
  • Dizziness or passing out.
  • Chest pain or pressure or a fast heartbeat.
  • Shakiness, trouble moving around, or stiffness.
  • Feeling confused.
  • Mood changes.
  • Seizures.
  • Swelling in the arms or legs.
  • Change in eyesight.
  • Feeling very sleepy.
  • Feeling very tired or weak.
  • Restlessness.
  • Pale skin.
  • Enlarged breasts.
  • Nipple discharge.
  • Sex problems like lowered interest in sex or ejaculation problems.
  • Period (menstrual) changes.
  • Some people who take this drug may get a very bad muscle problem called tardive dyskinesia. This muscle problem may not go away even if this drug is stopped. Sometimes, signs may lessen or go away over time after this drug is stopped. The risk of tardive dyskinesia may be greater in people with diabetes and in older adults, especially older women. The risk is also greater the longer you take this drug or with higher doses. Muscle problems may also occur after short-term use with low doses. Call your doctor right away if you have trouble controlling body movements or if you have muscle problems with your tongue, face, mouth, or jaw like tongue sticking out, puffing cheeks, mouth puckering, or chewing.
  • A very bad and sometimes deadly health problem called neuroleptic malignant syndrome (NMS) may happen. Call your doctor right away if you have any fever, muscle cramps or stiffness, dizziness, very bad headache, confusion, change in thinking, fast heartbeat, heartbeat that does not feel normal, or are sweating a lot.

What are some other side effects of this drug?

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:

These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.

You may report side effects to the FDA at 1-800-FDA-1088. You may also report side effects at http://www.fda.gov/medwatch.

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]

Cardiovascular

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]

Psychiatric

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

Dermatologic

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

Gastrointestinal

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

Genitourinary

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

Hematologic

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

Ocular

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]

Other

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

Musculoskeletal

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

Respiratory

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

Hepatic

Frequency not reported: Jaundice, biliary stasis[Ref]

Endocrine

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

Metabolic

Frequency not reported: Anorexia, weight gain[Ref]

References

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

Further information

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.

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