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Pronunciation: THYE-oh-THIX-een
Class: Antipsychotic agent, Thioxanthene derivative

Trade Names

- Capsules, oral 2 mg
- Capsules, oral 10 mg
- Capsules, oral 20 mg

- Capsules, oral 1 mg
- Capsules, oral 5 mg


Produces antipsychotic effects, apparently because of dopamine-receptor blocking in CNS.

Slideshow: First Aid for Mental Health: 10 Drugs in the Pipeline

Indications and Usage

Management of schizophrenia.


Circulatory collapse; comatose states; CNS depression due to any cause; blood dyscrasias; hypersensitivity to any component of the product; possible cross-sensitivity to the phenothiazines.

Dosage and Administration

Adults and Children 12 y and older Initial dosage Mild conditions

PO 2 mg 3 times per day. Increase to 15 mg/day if indicated.

Severe conditions

PO 5 mg twice daily.

Maintenance dosage

PO 20 to 30 mg/day. Increase to 60 mg/day if indicated. Exceeding a total daily dosage of 60 mg/day rarely increases the beneficial response.


Store between 68° and 77°F. Protect from light.

Drug Interactions

Alcohol, barbiturates, other CNS depressants

May cause additive CNS depressant effects. Use with caution and carefully adjust the dosage. Avoid concurrent use of alcohol.

Anticholinergics (eg, atropine, benztropine)

May potentiate the anticholinergic effects of atropine-type drugs. Use with caution.


May inhibit hypotensive effect of guanethidine. Monitor BP and adjust the guanethidine dose as needed. Consider alternative therapy.

Hepatic microsomal enzyme–inducing agents (eg, carbamazepine)

Thiothixene plasma concentrations may be reduced, decreasing the efficacy. Monitor for reduced signs of thiothixene effectiveness.

Hypotensive agents

Excessive hypotension may result from additive effects. Closely monitor BP.


The risk of neurotoxicity, including extrapyramidal symptoms, may be increased. Closely monitor patients for neurotoxicity. If an interaction is suspected, consider reducing the dose of one or both agents or discontinuing one of the drugs.


The risk of seizures may be increased. Coadministration is not recommended.

Laboratory Test Interactions

Phenothiazines have been associated with false-positive pregnancy tests.

Adverse Reactions


Hypotension, nonspecific ECG changes, syncope, tachycardia.


Agitation; drowsiness; extrapyramidal symptoms, including akathisia, dystonia, and pseudoparkinsonism; fatigue/weakness; insomnia; light-headedness; paradoxical exacerbation of psychotic symptoms; restlessness; sedation; seizures; tardive dyskinesia.


Increased sweating, photosensitivity, pruritus, rash, urticaria.


Blurred vision, nasal congestion.




Anorexia, constipation, diarrhea, dry mouth, increased appetite, increased salivation, nausea, vomiting.


Amenorrhea, breast enlargement, impotence, lactation, menstrual irregularities.


Leukocytosis, leukopenia.


Elevated alkaline phosphatase, elevated serum transaminases.


Increased weight, peripheral edema.


Anaphylaxis, hyperpyrexia, NMS, polydipsia.



Increased mortality

Elderly patients with dementia-related psychosis treated with antipsychotic drugs are at an increased risk of death. Over the course of a 10-wk controlled trial, the rate of death in drug-treated patients was approximately 4.5% compared with 2.6% in the placebo group. Although the causes of death were varied, most of the deaths appeared to be either CV (eg, heart failure, sudden death) or infectious (eg, pneumonia) in nature.

Observational studies suggest that similar to atypical antipsychotic drugs, treatment with conventional antipsychotic drugs may increase mortality. Thiothixene is not approved for the treatment of patients with dementia-related psychosis.


Monitor for pigmentary retinopathy and lenticular pigmentation. Monitor for blood dyscrasias (agranulocytosis, pancytopenia, thrombocytopenic purpura) and liver damage (jaundice, biliary stasis). Monitor patients with clinically significant neutropenia for fever or other symptoms/signs of infection. Monitor for tardive dyskinesia. Patients requiring antipsychotic drug treatment after recovery from NMS should be monitored for recurrence of NMS if thiothixene therapy is reintroduced.


Pregnancy category undetermined.




Safety and efficacy not established in children younger than 12 y.

Special Risk Patients

Use drug with caution in patients with CV disease.

Antiemetic effect

Because thiothixene may have an antiemetic effect, signs and symptoms of overdosage with certain drugs or conditions (eg, brain tumor, intestinal obstruction) may be masked.

Blood dyscrasias

Agranulocytosis, pancytopenia, and thrombocytopenic purpura have been reported with related drugs.

Body temperature regulation

Use with caution in patients who might be exposed to extreme heat or who are receiving atropine or related drugs.

Cognitive and motor performance

Thiothixene may impair mental or physical abilities, especially during first few days of therapy.


Prolactin levels may be elevated.


NMS has occurred with similar agents and is potentially fatal. Signs and symptoms are hyperpyrexia, muscle rigidity, altered mental status, irregular pulse, irregular BP, tachycardia, and diaphoresis.

Ophthalmic effects

Pigmentary retinopathy and lenticular pigmentation (fine lenticular pigmentation) have been noted in a small number of patients treated with thiothixene for prolonged periods.


May occur; use with caution in patients with a history of seizures or other conditions that potentially lower the seizure threshold (eg, alcohol withdrawal).

Tardive dyskinesia

Potentially irreversible involuntary body and facial movements may occur. Prevalence is highest in elderly patients, especially women.



CNS depression, coma, disturbances of gait, dizziness, drowsiness, dysphagia, hypotension, muscular twitching, rigidity, salivation, torticollis, tremor, weakness.

Patient Information

  • Advise patients, families, or caregivers that dose will be adjusted periodically until maximum benefit has been obtained.
  • Instruct patients not to stop taking thiothixene when feeling better.
  • Instruct patients, families, or caregivers to immediately report fainting, dizziness, high fever, muscle rigidity, altered mental status, and irregular pulse.
  • Advise patients, families, or caregivers to notify health care provider of the following: excessive drowsiness, increased agitation or anxiety, involuntary body or facial movements.
  • Advise patients to avoid strenuous activity during periods of high temperature or humidity.
  • Instruct patients to avoid alcoholic beverages and other depressants while taking this medication.
  • Instruct patients to get up slowly from lying or sitting position and to avoid sudden position changes to prevent postural hypotension. Advise patients to report dizziness with position changes to their health care provider. Caution patients that hot tubs and hot showers or baths may worsen dizziness.
  • Advise patients to take sips of water, suck on ice chips or sugarless hard candy, or chew sugarless gum if dry mouth occurs.
  • Advise patients that thiothixene may cause drowsiness or impaired judgment, thinking, or motor skills and to use caution while driving or performing other tasks requiring mental alertness until tolerance is determined.
  • Caution patients that medication may cause sensitivity to sunlight and to avoid unnecessary exposure to UV light (eg, sunlight, tanning booths) and to use sunscreen and wear protective clothing when exposed to UV light until tolerance is determined.

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