Mellaril

Generic name: thioridazine

Drug class: Phenothiazine antipsychotics

Dosage form: Oral tablets

Root of administration: Oral

Dose: Typically, 50 mg to 100 mg taken three times daily, with a maximum daily dose of 800 mg. Elderly patients may start with 25 mg to 50 mg daily.

Mechanism of action: Thioridazine is a low-potency, first-generation antipsychotic that primarily blocks dopamine D2 receptors in the brain, reducing symptoms of schizophrenia such as hallucinations and delusions. It also exhibits significant anticholinergic, antihistaminergic, and alpha-adrenergic blocking properties, contributing to its therapeutic and side effect profile.

Drug usage cases:

• Treatment-resistant schizophrenia
• Acute manic episodes associated with bipolar disorder
• Severe behavioral problems in children

Drug contraindications:

• Known hypersensitivity to thioridazine or other phenothiazines
• Severe central nervous system depression
• Comatose states
• Severe cardiovascular disorders, including QT interval prolongation
• Untreated or uncontrolled high blood pressure
• Severe liver impairment
• Concurrent use with other medications that prolong the QT interval

Side effects:

• Extrapyramidal symptoms: tremors, rigidity, bradykinesia, tardive dyskinesia
• Anticholinergic effects: dry mouth, blurred vision, constipation, urinary retention
• Cardiovascular effects: QT interval prolongation, torsades de pointes, sudden death
• Endocrine effects: hyperprolactinemia leading to galactorrhea, gynecomastia, menstrual irregularities
• Hematologic effects: agranulocytosis, leukopenia
• Neurological effects: seizures, neuroleptic malignant syndrome
• Metabolic effects: weight gain, hyperglycemia
• Dermatologic effects: photosensitivity, skin rashes
• Other effects: sedation, dizziness, orthostatic hypotension

Warnings:

• Thioridazine is associated with a dose-related prolongation of the QT interval, which can lead to torsades de pointes and sudden death. It should be used with caution, especially in patients with a history of cardiac arrhythmias.
• Not approved for use in elderly patients with dementia-related psychosis due to an increased risk of death.
• Use with caution in patients with a history of seizures, liver or kidney disease, or bone marrow depression.
• May cause neuroleptic malignant syndrome, a potentially fatal condition characterized by hyperthermia, muscle rigidity, altered mental status, and autonomic dysregulation.
• Use with caution in patients with a history of cardiovascular disease, including heart failure, arrhythmias, or recent myocardial infarction.
• May cause significant anticholinergic effects; monitor for signs of anticholinergic toxicity.
• Monitor for signs of tardive dyskinesia, especially with long-term use.
• Alcohol and other central nervous system depressants may enhance sedative effects; concurrent use should be avoided.

Use during pregnancy or breastfeeding:

Thioridazine is classified as a Category C medication for pregnancy, indicating that risk to the fetus cannot be ruled out. It should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Thioridazine is excreted in breast milk; therefore, breastfeeding is not recommended during treatment.