Thioridazine, more commonly known as Mellaril, is one of the first generation antipsychotic medications. It is a type of phenothiazine, and is also considered a neuroleptic medication. This is because some of the side affects it inadvertently causes are neurological in nature.

What it’s used to treat

Thioridazine is used primarily in the treatment of individuals with schizophrenia. Because of its potentially very serious side effects, it is usually not prescribed until other antipsychotic medications have been tried first. If those have been ineffective, then thioridazine is at times considered.

It is also used, at times, for the treatment of anxiety, very serious depression, dementia, and agitation.

How it works

As with most antipsychotic medications, the exact way in which Thioridazine works in the brain is not really understood. It does impact the neurotransmitter dopamine, which is believed to be higher than normal in schizophrenics. The drug blocks dopamine receptors, and thus reduces dopamine’s effects on the individual. Unfortunately, it does not cure schizophrenia, but is often effective in keeping many of the symptoms, such as hallucinations and delusions, under control.

How it’s administered

Thioridazine comes in tablet form, and is typically taken orally. It may be prescribed to be taken up to three times each day.

Potential Side Effects

Some of the most common side effects of this medication include the following (not a complete list):

  • Sedation
  • Nausea or vomiting
  • Tremors, twitches, or other abnormal physical movements
  • Blurred vision
  • Urination difficulties
  • Dry mouth
  • Constipation
  • Feelings of restlessness
  • Confusion
  • Decreased appetite
  • Weight gain

Tardive dyskinesia (TD) and neuroleptic malignant syndrome (NMS) are also side effects of thioridazine. These are typical potential side effects of many antipsychotic medications, and should always be considered when determining the best drug treatment for schizophrenia.

Tardive dyskinesia

Tardive dyskinesia involves random and uncontrollable muscle spasms. The person may exhibit twitches in the face and other parts of the body, grimacing, tongue smacking, and other unusual movements. Because TD can become irreversible, it can be especially troublesome.

Neuroleptic malignant syndrome

NMS is potentially fatal. Symptoms of NMS include fluctuations in heart beat and blood pressure, rigidity in the muscles, high fever, confusion, sweating, and rapid heart beat.

Because of these potentially fatal side effects, this medication is used more as last resort after other drugs have failed. In fact, Canada and other countries have stopped the use of thioridazine because the risks are considered too high.1. 2.


As with any medication, there are several precautions one must take. If you are considering taking thioridazine, it is important to tell your doctor if you have any history of heart arrhythmias, epilepsy, unusually low or high blood pressure, drug allergies or other types of allergies, urination problems, prostrate problems or glaucoma. Also, be sure to let your doctor know if you are pregnant, thinking about becoming pregnant, or if you are nursing.

Also, because it may interact with other medications, be sure to tell your doctor about any other medications (and supplements) you may be taking.


  1. Canada Halts Sales of Thioridazine, 2005
  2. Discontinuation of Thioridazine: Risks Must be Balanced, British Medical Journal, 2002

written by Dr. Cheryl Lane, PsyD