thioridazine (Mellaril [discontinued])

Thioridazine is an oral antipsychotic medication used for the management of schizophrenia. Thioridazine is one of the older, first-generation antipsychotic medications. Examples of other first-generation antipsychotics include:

• prochlorperazine (Compazine, Compro, Procomp)
• chlorpromazine (Promapar, Thorazine)
• perphenazine (Trilafon)
• trifluoperazine (Stelazine)

Although the exact mechanism of antipsychotics is unknown, scientists believe that they may work by blocking the action of dopamine in the brain. Dopamine is a neurotransmitter (chemical) that nerves use to communicate with one another. Thioridazine is used when patients do not respond to other antipsychotics.

Is thioridazine available as a generic drug?

Yes

Do I need a prescription for thioridazine?

Yes

Thioridazine causes extrapyramidal side effects such as:

• Abnormal muscle contractions
• Difficulty breathing and swallowing
• Neck spasms

Other side effects include:

• Low blood pressure
• Constipation
• Dry mouth
• Blurred vision
• Seizures
• Dizziness
• Drowsiness
• Urinary retention
• Worsening of glaucoma
• Increased or decreased blood glucose

• The recommended starting dose of thioridazine for treating schizophrenia is 50 to 100 mg every 8 hours.
• Maintenance is recommended with doses every 6-12 hours with a total daily dose of 200 to 800 mg.
• The dose for treating depressive disorders is 25 mg every 8 hours. The dose may be increased slowly to 20 to 200 mg daily.

Combining thioridazine with medications such as procainamide (Pronestyl), sotalol (Betapace), amiodarone (Cordarone), and dofetilide (Tikosyn) that affect heart rate and rhythm can cause abnormal heart beats.

Antidepressants such as fluoxetine (Prozac), sertraline (Zoloft) and tricyclic antidepressants may reduce the breakdown of thioridazine, leading to increased blood levels and side effects of thioridazine.

Thioridazine should be used with caution with medications that depress the central nervous system and cause sedation or drowsiness. Examples include alprazolam (Xanax), clonazepam (Klonopin), zolpidem (Ambien), codeine, morphine, and alcohol. Such combinations can cause excessive sedation, drowsiness, weakness, confusion, speech impairment, and in severe cases coma or death. Combining alcohol with thioridazine also increases the risk of low blood pressure.

Use of thioridazine during pregnancy has not been adequately studied. Infants exposed to antipsychotics during the third trimester of pregnancy are at risk for extrapyramidal and withdrawal symptoms after birth. Symptoms reported included agitation, hypertonia, hypotonia, tremor, somnolence, depressed breathing, and feeding disorder.

Safe use of thioridazine by nursing mothers has not been established.

What preparations of thioridazine are available?

Tablets: 10, 25, 50 and 100 mg.

How should I keep thioridazine stored?

Thioridazine tablets should be stored between 15 C and 30 C (59 F and 86 F).