Thioridazine Side Effects

Brand Names: Mellaril

Please note - some side effects for Thioridazine may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA at http://www.fda.gov/medwatch/ or 1-800-FDA-1088 (1-800-332-1088).

Side Effects of Thioridazine - for the Consumer

Thioridazine

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome when using Thioridazine:

Agitation; bizarre dreams; constipation; diarrhea; dizziness; drowsiness; dry mouth; loss of appetite; nausea; stuffy nose; vomiting.

Severe allergic reactions (rash; hives; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); changes in menstrual period; changes in sexual ability; chest pain; confusion; dark urine; difficulty swallowing; drooling; fainting; fast, slow, or irregular heartbeat; fever, chills, or sore throat; hyperactivity; involuntary movements or spasms of the arms, legs, tongue, face, mouth, or jaw; mask-like face; muscle restlessness; restlessness; seizures; severe or persistent dizziness; severe constipation; shuffling walk; sleeplessness; sore mouth or gums; stiff or rigid muscles; stomach pain; sweating; swelling of the hands or feet; trouble urinating; unusual bruising or bleeding; unusual eye movements or inability to move eyes; unusual mood or mental changes, including lack of response to your surroundings; vision changes; weakness of arms or legs; yellowing of the skin or eyes.

Thioridazine Concentrate

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome when using Thioridazine Concentrate:

Agitation; bizarre dreams; constipation; diarrhea; dizziness; drowsiness; dry mouth; loss of appetite; nausea; stuffy nose; vomiting.

Severe allergic reactions (rash; hives; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); changes in menstrual period; changes in sexual ability; chest pain; confusion; dark urine; difficulty swallowing; drooling; fainting; fast, slow, or irregular heartbeat; fever, chills, or sore throat; hyperactivity; involuntary movements or spasms of the arms, legs, tongue, face, mouth, or jaw; mask-like face; muscle restlessness; restlessness; seizures; severe or persistent dizziness; severe constipation; shuffling walk; sleeplessness; sore mouth or gums; stiff or rigid muscles; stomach pain; sweating; swelling of the hands or feet; trouble urinating; unusual bruising or bleeding; unusual eye movements or inability to move eyes; unusual mood or mental changes, including lack of response to your surroundings; vision changes; weakness of arms or legs; yellowing of the skin or eyes.

Thioridazine Side Effects - for the Professional

Thioridazine

In the recommended dosage ranges with Thioridazine HCl most side effects are mild and transient.

Central Nervous System: Drowsiness may be encountered on occasion, especially where large doses are given early in treatment. Generally, this effect tends to subside with continued therapy or a reduction in dosage. Pseudoparkinsonism and other extrapyramidal symptoms may occur but are infrequent. Nocturnal confusion, hyperactivity, lethargy, psychotic reactions, restlessness, and headache have been reported but are extremely rare.

Autonomic Nervous System: Dryness of mouth, blurred vision, constipation, nausea, vomiting, diarrhea, nasal stuffiness, and pallor have been seen.

Endocrine System: Galactorrhea, breast engorgement, amenorrhea, inhibition of ejaculation, and peripheral edema have been described.

Skin: Dermatitis and skin eruptions of the urticarial type have been observed infrequently. Photosensitivity is extremely rare.

Cardiovascular System: Thioridazine HCl produces a dose related prolongation of the QTc interval, which is associated with the ability to cause torsade de pointes-type arrhythmias, a potentially fatal polymorphic ventricular tachycardia, and sudden death. Both torsade de pointes-type arrhythmias and sudden death have been reported in association with Thioridazine. A causal relationship between these events and Thioridazine therapy has not been established but, given the ability of Thioridazine to prolong the QTc interval, such a relationship is possible. Other ECG changes have been reported.

Other: Rare cases described as parotid swelling have been reported following administration of Thioridazine.

Post Introduction Reports

These are voluntary reports of adverse events temporally associated with Thioridazine HCl that were received since marketing, and there may be no causal relationship between Thioridazine use and these events: priapism.

Phenothiazine Derivatives

It should be noted that efficacy, indications, and untoward effects have varied with the different phenothiazines. It has been reported that old age lowers the tolerance for phenothiazines. The most common neurological side effects in these patients are parkinsonism and akathisia. There appears to be an increased risk of agranulocytosis and leukopenia in the geriatric population. The physician should be aware that the following have occurred with one or more phenothiazines and should be considered whenever one of these drugs is used:

Autonomic Reactions: Miosis, obstipation, anorexia, paralytic ileus.

Cutaneous Reactions: Erythema, exfoliative dermatitis, contact dermatitis.

Blood Dyscrasias: Agranulocytosis, leukopenia, eosinophilia, thrombocytopenia, anemia, aplastic anemia, pancytopenia.

Allergic Reactions: Fever, laryngeal edema, angioneurotic edema, asthma.

Hepatotoxicity: Jaundice, biliary stasis.

Cardiovascular Effects: Changes in the terminal portion of the electrocardiogram to include prolongation of the QT interval, depression and inversion of the T wave, and the appearance of a wave tentatively identified as a bifid T wave or a U wave have been observed in patients receiving phenothiazines, including Thioridazine. To date, these appear to be due to altered repolarization, not related to myocardial damage, and reversible. Nonetheless, significant prolongation of the QT interval has been associated with serious ventricular arrhythmias and sudden death. Hypotension, rarely resulting in cardiac arrest, has been reported.

Extrapyramidal Symptoms: Akathisia, agitation, motor restlessness, dystonic reactions, trismus, torticollis, opisthotonus, oculogyric crises, tremor, muscular rigidity, akinesia.

Tardive Dyskinesia: Chronic use of antipsychotics may be associated with the development of tardive dyskinesia. The salient features of this syndrome are described in the WARNINGS section and subsequently.

The syndrome is characterized by involuntary choreoathetoid movements which variously involve the tongue, face, mouth, lips, or jaw (e.g., protrusion of the tongue, puffing of cheeks, puckering of the mouth, chewing movements), trunk, and extremities. The severity of the syndrome and the degree of impairment produced vary widely.

The syndrome may become clinically recognizable either during treatment, upon dosage reduction, or upon withdrawal of treatment. Movements may decrease in intensity and may disappear altogether if further treatment with antipsychotics is withheld. It is generally believed that reversibility is more likely after short rather than long-term antipsychotic exposure. Consequently, early detection of tardive dyskinesia is important. To increase the likelihood of detecting the syndrome at the earliest possible time, the dosage of antipsychotic drug should be reduced periodically (if clinically possible) and the patient observed for signs of the disorder. This maneuver is critical, for antipsychotic drugs may mask the signs of the syndrome.

Neuroleptic Malignant Syndrome (NMS): Chronic use of antipsychotics may be associated with the development of Neuroleptic Malignant Syndrome. The salient features of this syndrome are described in the WARNINGS section and subsequently. Clinical manifestations of NMS are hyperpyrexia, muscle rigidity, altered mental status, and evidence of autonomic instability (irregular pulse or blood pressure, tachycardia, diaphoresis, and cardiac dysrhythmias).

Endocrine Disturbances: Menstrual irregularities, altered libido, gynecomastia, lactation, weight gain, edema. False positive pregnancy tests have been reported.

Urinary Disturbances: Retention, incontinence.

Others: Hyperpyrexia. Behavioral effects suggestive of a paradoxical reaction have been reported. These include excitement, bizarre dreams, aggravation of psychoses, and toxic confusional states. More recently, a peculiar skin-eye syndrome has been recognized as a side effect following long-term treatment with phenothiazines. This reaction is marked by progressive pigmentation of areas of the skin or conjunctiva and/or accompanied by discoloration of the exposed sclera and cornea. Opacities of the anterior lens and cornea described as irregular or stellate in shape have also been reported. Systemic lupus erythematosus-like syndrome.

Side Effects by Body System

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 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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