Thioridazine: Chemical Formula, Indications, Mechanism of Action, Dosage, Side Effects, Warnings and Interactions

It is an antipsychotic drug previously used in the treatment of schizophrenia and psychosis.

Due to concerns about cardiotoxicity and high-dose retinopathy, this drug is now less prescribed and used primarily for refractory cases.

Thioridazine was initially introduced in 1959 for the treatment of psychosis.

Thioridazine is usually given after other antipsychotic medications have been tried without success.

Chemical formula

  • C21H26N2S2HCl.

Presentation

The presentation is in tablets of 10, 25, 50 and 100 mg.

Indications

Thioridazine is used to treat schizophrenia .

Mechanism of action

Thioridazine blocks postsynaptic D1 and D2 dopamine receptors in the brain; blocks the alpha-adrenergic effect.

It depresses the release of hypothalamic and pituitary hormones and is believed to depress the reticular activation system, affecting basal metabolism, body temperature, wakefulness, vasomotor tone, and emesis.

Dose

For the treatment of schizophrenia, a starting dose of 50 to 100 mg, orally every 8 hours, is generally recommended. Increasing the dose from 200 to 800 mg, orally divided every 6 to 12 hours a day.

For the treatment of depressive disorders, the recommended dose is 25 mg, orally every 8 hours.

Side effects

Common side effects can include:

  • Drowsiness.
  • Dry mouth, blurred vision.
  • Nausea, vomiting, constipation , diarrhea.
  • Swelling or discharge from the breasts.
  • Changes in menstrual periods.
  • Swelling in the hands or feet

Stop using thioridazine and call your doctor at once if you have:

  • Uncontrollable muscle movements in the face (chewing, smacking the lips, frowning, moving the tongue, blinking, or moving the eyes).
  • Shaking, drooling, trouble swallowing, trouble balancing or walking.
  • Headache.
  • Confusion, slurred speech.
  • Sudden weakness or feeling, fever, chills, sore throat, swollen gums, painful mouth sores, pain when swallowing, skin sores, cold or flu symptoms, cough.
  • Dizziness or severe headaches
  • Presence of oliguria or anuria.
  • Decreased night vision, tunnel vision, watery eyes, increased sensitivity to light.
  • Allergic reaction with the presence of swelling of the face, mouth, tongue or throat and difficulty in breathing.
  • Seizures

Warnings and Contraindications

You should not use thioridazine if you have a heart rhythm disorder, a history of long QT syndrome, uncontrolled or uncontrolled high blood pressure, very low blood pressure, or if you have drowsiness, slow breathing, a weak pulse, or decreased alertness.

You should not use thioridazine if:

  • You have heart disease, high blood pressure, or a heart rhythm disorder.
  • You have had or have breast cancer .
  • You have liver or kidney disease.
  • Severe asthma, emphysema, or some other breathing problem.
  • You have a history of seizures.
  • He suffers from Parkinson’s disease.
  • Tumor in the adrenal gland.
  • You have an enlarged prostate or urination problems.
  • You have low levels of calcium in your blood (hypocalcemia).
  • You have glaucoma.
  • If you have ever had a serious side effect while using thioridazine or another phenothiazine.

The longer you take thioridazine, movement disorders are likely to develop, such as uncontrollable muscle movements of the lips, tongue, eyes, face, arms, or legs, which may not be reversible in the long run.

This side effect occurs more often in women and older adults.

Tell your doctor if you are pregnant or plan to become pregnant while using this medicine, as antipsychotic medicines can affect the fetus in the last three months of gestation.

If you become pregnant while taking thioridazine, do not stop taking it without your doctor’s advice. It is not known whether thioridazine passes into breast milk. So you should inform your doctor if you are breastfeeding a baby.

Avoid driving vehicles or operating machinery or doing any activity that requires alertness.

To avoid a fall, try not to get up too quickly from a sitting or lying position, as you may feel dizzy.

While using thioridazine, you may need frequent blood tests. You may need to check your heart function with an EKG.

If you need surgery, tell the surgeon ahead of time that you are using thioridazine.

Interactions

Thioridazine can cause a life-threatening heart rhythm disorder, especially if you use certain medications at the same time.

Many medications should not be taken together with thioridazine, including certain antibiotics, antidepressants, heart or blood pressure medications.

Other antipsychotic medications and medications to treat migraine or certain narcotic pain medications, medications to prevent or treat nausea and vomiting, cancer, malaria, or AIDS.