Mellaril Side Effects

Generic name: thioridazine

Note: This document contains side effect information about thioridazine. Some of the dosage forms listed on this page may not apply to the brand name Mellaril.

Some side effects of Mellaril may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

For the Consumer

Applies to thioridazine: oral tablet

Get emergency medical help if you have any of these signs of an allergic reaction while taking thioridazine (the active ingredient contained in Mellaril) hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Stop using thioridazine and call your doctor at once if you have a serious side effect such as:

• headache with chest pain and severe dizziness, fainting, fast or pounding heartbeats;

• slow heart rate, weak pulse, fainting, slow breathing;

• very stiff (rigid) muscles, high fever, sweating, confusion, fast or uneven heartbeats, feeling like you might pass out;

• twitching or uncontrollable movements of your eyes, lips, tongue, face, arms, or legs;

• tremor (uncontrolled shaking), drooling, trouble swallowing, problems with balance or walking;

• feeling restless, jittery, or agitated;

• seizure (convulsions);

• decreased night vision, tunnel vision, watery eyes, increased sensitivity to light;

• pale skin, easy bruising or bleeding, fever, chills, flu symptoms, sores in your mouth and throat;

• urinating less than usual or not at all; or

• nausea and upper stomach pain, itching, and jaundice (yellowing of the skin or eyes).

Less serious side effects of thioridazine may include:

• drowsiness;

• dry mouth, stuffy nose;

• vomiting, constipation, diarrhea;

• breast swelling or discharge;

• changes in your menstrual periods;

• weight gain, swelling in your hands or feet;

• impotence, trouble having an orgasm;

• increased or decreased interest in sex; or

• mild itching or skin rash.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects.

For Healthcare Professionals

Applies to thioridazine: oral concentrate, oral suspension, oral tablet

Nervous system

Nervous system side effects including drowsiness have occasionally been reported. Pseudoparkinsonism and other extrapyramidal symptoms have infrequently been reported. Nocturnal confusion, hyperactivity, lethargy, psychotic reactions, restlessness, and headache have been reported extremely rarely.

Drowsiness has been reported to subside with continuation of therapy or a reduction in dosage.

Cardiovascular

Cardiovascular side effects including prolongation of the QTc interval have been reported. Prolongation of the QTc interval occurs in a dose related manner which has been associated with torsades de pointes type arrhythmias and sudden death. A case of acute hypotension and a case of massive edema have also been reported.

Baseline ECG and serum potassium levels are recommend for patients being considered for treatment with thioridazine. Thioridazine is not recommended for use in patients with a QTc interval greater than 450 msec. It is recommended that serum potassium levels be normalized before initiation of therapy.

Once the patient is receiving thioridazine, periodic ECG's and serum potassium levels are recommended. Discontinuation of therapy is recommended if patients are found to have a QTc interval over 500 msec.

Gastrointestinal

Gastrointestinal side effects including dryness of the mouth, constipation, nausea, vomiting, and diarrhea have been reported. Obstipation, anorexia, and paralytic ileus has been reported with the use of phenothiazine derivatives.

Ocular

Ocular side effects including retinopathy and blurred vision have been reported. Miosis has been reported with the use of phenothiazine derivatives.

Respiratory

Respiratory side effects including nasal stuffiness have been reported.

Dermatologic

Dermatologic side effects including pallor have been reported. Dermatitis and urticarial skin eruptions have been reported infrequently. Photosensitivity has been reported extremely rarely. Erythema, exfoliative dermatitis, and contact dermatitis have been reported with the use of phenothiazine derivatives.

Endocrine

Endocrine side effects including galactorrhea, breast engorgement, amenorrhea, inhibition of ejaculation and peripheral edema have been reported. Menstrual irregularities, altered libido, gynecomastia, lactation, weight gain, edema, and false positive pregnancy tests have been reported with the use of phenothiazine derivatives.

Other

Other side effects including parotid swelling have been reported.

Hematologic

Hematologic side effects including agranulocytosis have been report. Leukopenia, eosinophilia, thrombocytopenia, anemia, aplastic anemia, and pancytopenia have been reported with the use of phenothiazine derivatives.

Hepatic

Hepatic side effects including individual cases of cholestasis, elevated transaminase levels, and clinical jaundice have been reported. Biliary stasis have been reported with the use of phenothiazine derivatives.

Psychiatric

Psychiatric side effects including agitation have been reported in patients receiving phenothiazine derivatives. A case report of thioridazine (the active ingredient contained in Mellaril) induced toxic psychosis has also been reported.

Musculoskeletal

Musculoskeletal side effects including tardive dyskinesia has been reported with the use of phenothiazine derivatives.

Genitourinary

Genitourinary side effects including ejaculatory problems (60% in a study of 57 male patients) have been reported. One third of these patients experienced retrograde ejaculation. Urinary incontinence and priapism have also been reported. Urinary retention been reported with the use of phenothiazine derivatives.

General

General side effects including hyperpyrexia have been reported with the use of phenothiazine derivatives. Behavioral effects suggestive of a paradoxical reaction which included excitement, bizarre dreams, aggravation of psychosis and toxic confusional states have also been reported with the use of phenothiazine derivatives.

Metabolic

Metabolic side effects include one case of exacerbation of diabetes which has been reported.

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