Mesoridazine is a member of the phenothiazine family of drugs (drugs that reduce the action of the neurotransmitter, dopamine, in the brain ) and sold under the brand name Serentil in the United States.


Mesoridazine is effective in the treatment of schizophrenia , alcoholism, psychoneuroses (disorders of the brain), and organic brain disorders (disorders caused by temporary brain dysfunction or permanent brain damage).


When used for the treatment of schizophrenia, mesoridazine reduces symptoms of emotional withdrawal, anxiety, tension, hallucinations , reduced affect , and paranoia (suspiciousness). It is often useful in persons for whom other tranquilizers are ineffective. In treating organic brain syndrome, mesoridazine effectively manages hyperactivity and difficult behaviors associated with mental deficiency. Mesoridazine relieves anxiety, nausea, vomiting, tension, and depression when used to treat alcoholism. It does not have side effects that affect liver function. It relieves similar symptoms when used to treat persons with psychoneurotic disorders.

Mesoridazine can be taken by mouth or given by intramuscular injection. It is supplied as 25 mg/mL in injection form, and in 10-, 25-, 50-, and 100-mg tablets.

Recommended dosage

The usual dosage used for treating schizophrenia is 50–400 mg per day and is usually administered three times per day. It is begun at a low level and slowly increased until an adequate therapeutic effect is achieved. For persons with organic brain syndrome, an optimum dosage is 75–300 mg per day, administered in three equal amounts. The optimum dosage for persons being treated for alcoholism is 50–300 mg per day, administered in three doses. The usual dosage range for persons with psychoneuroses is 30–150 mg per day, administered in three equal amounts.


Mesoridazine has the potential to produce a serious syndrome called tardive dyskinesia . This syndrome consists of involuntary, uncoordinated movements (especially of the tongue, jaw, mouth, or face). It usually develops either late in the course of treatment or after medication has been discontinued and is potentially irreversible. Symptoms similar to those experienced by people with Parkinson's disease have been linked with the administration of mesoridazine. Mesoridazine is inappropriate for use with central nervous system depression, nor should it be administered to persons in a coma.

Side effects

A serious and relatively common side effect of mesoridazine is tardive dyskinesia, a potentially irreversible syndrome for which there is no known effective treatment. An important feature of tardive dyskinesia is that it typically develops either late into treatment or after treatment has ceased. Tardive dyskinesia consists of involuntary, uncoordinated movements of the tongue, jaw, mouth, or face that also may be accompanied by involuntary movements of the arms, legs, and trunk. The chances of developing tardive dyskinesia increase with both increasing dosage and increasing patient age.

The most common side effects of mesoridazine are drowsiness and low blood pressure and are most frequently reported in persons given relatively high dosages. Side effects also tend to appear relatively early in treatment. Mesoridazine tends to have a remarkably low incidence of side effects compared to other phenothiazine compounds. However, as mentioned, Parkinsonlike symptoms have been linked with the administration of mesoridazine. These include restlessness and agitation (akathisia) and difficulty walking or moving (dystonia). These are generally controlled with benztropine mesylate or trihexyphenidyl hydrochloride.

Other known side effects include anxiety, restlessness, agitation, insomnia , headache, euphoria, drowsiness, depression, confusion, and dizziness. Unwanted or unexpected effects associated with the use of mesoridazine have been reported for virtually all organ systems in the body. Although numerous, such side effects are relatively uncommon. An occasionally reported side effect is neuroleptic malignant syndrome, a complicated and potentially fatal condition characterized by muscle rigidity, high fever, alterations in mental status, and cardiac symptoms such as irregular pulse or blood pressure, sweating, tachycardia and arrhythmias.


Mesoridazine increases the effect of drugs and substances that depress the central nervous system. This class of drugs includes anesthetics, opiates, barbiturates , atropine, and alcohol.

See also Alcohol and related disorders



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American Academy of Clinical Toxicology. 777 East Park Drive, PO Box 8820, Harrisburg, PA 17105-8820. Telephone: (717) 558-7750. Fax: (717) 558-7845. Web site: <> .

American Academy of Family Physicians. 11400 Tomahawk Creek Parkway, Leawood, KS 66211-2672. Telephone:(913) 906-6000. Web site: <> .

American Medical Association. 515 N. State Street, Chicago, IL 60610. Telephone: (312) 464-5000. Web site: <> .

American Psychiatric Association. 1400 K Street NW, Washington, DC 20005. Telephone: (888) 357-7924. Fax(202) 682-6850. Web site: <> .

American Society for Clinical Pharmacology and Therapeutics. 528 North Washington Street, Alexandria, VA 22314. Telephone: (703) 836-6981 Fax: (703) 836-5223.

American Society for Pharmacology and Experimental Therapeutics. 9650 Rockville Pike, Bethesda, MD 20814-3995. Telephone: (301) 530-7060. Fax: (301) 530-7061. Web site: <> .

L. Fleming Fallon, Jr., M.D., Dr.P.H.

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