Thiothixene

What it is used for

Thiothixene capsules are effective in the management of schizophrenia. Thiothixene capsules have not been evaluated in the management of behavioral complications in patients with mental retardation.

How to take it

Dosage of thiothixene capsules should be individually adjusted depending on the chronicity and severity of the symptoms of schizophrenia. In general, small doses should be used initially and gradually increased to the optimal effective level, based on patient response.

Some patients have been successfully maintained on once-a-day thiothixene capsules therapy.

The use of thiothixene capsules in children under 12 years of age is not recommended because safe conditions for its use have not been established.

In milder conditions, an initial dose of 2 mg three times daily is recommended. If indicated, a subsequent increase to 15 mg/day total daily dose is often effective.

In more severe conditions, an initial dose of 5 mg twice daily is recommended.

The usual optimal dose is 20 mg to 30 mg daily. If indicated, an increase to 60 mg/day total daily dose is often effective. Exceeding a total daily dose of 60 mg rarely increases the beneficial response.

Side effects, and when to stop

NOTE: Not all of the following adverse reactions have been reported with thiothixene. However, since thiothixene has certain chemical and pharmacologic similarities to the phenothiazines, all of the known side effects and toxicity associated with phenothiazine therapy should be borne in mind when thiothixene is used.

Who should not take it

Thiothixene capsules are contraindicated in patients with circulatory collapse, comatose states, central nervous system depression due to any cause, and blood dyscrasias. Thiothixene capsules are contraindicated in individuals who have shown hypersensitivity to the drug. It is not known whether there is a cross sensitivity between the thioxanthenes and the phenothiazine derivatives, but this possibility should be considered.

Warnings

An antiemetic effect was observed in animal studies with thiothixene; since this effect may also occur in man, it is possible that thiothixene may mask signs of overdosage of toxic drugs and may obscure conditions such as intestinal obstruction and brain tumor.

In consideration of the known capability of thiothixene and certain other psychotropic drugs to precipitate convulsions, extreme caution should be used in patients with a history of convulsive disorders or those in a state of alcohol withdrawal, since it may lower the convulsive threshold.

Although thiothixene potentiates the actions of the barbiturates, the dosage of the anticonvulsant therapy should not be reduced when thiothixene is administered concurrently.

Though exhibiting rather weak anticholinergic properties, thiothixene should be used with caution in patients who might be exposed to extreme heat or who are receiving atropine or related drugs.

Use with caution in patients with cardiovascular disease.

Caution as well as careful adjustment of the dosages is indicated when thiothixene is used in conjunction with other CNS depressants.

Also, careful observation should be made for pigmentary retinopathy and lenticular pigmentation (fine lenticular pigmentation has been noted in a small number of patients treated with thiothixene for prolonged periods). Blood dyscrasias (agranulocytosis, pancytopenia, thrombocytopenic purpura), and liver damage (jaundice, biliary stasis) have been reported with related drugs.

Antipsychotic drugs, including thiothixene 3, elevate prolactin levels; the elevation persists during chronic administration. Tissue culture experiments indicate that approximately one-third of human breast cancers are prolactin dependent in vitro, a factor of potential importance if the prescription of these drugs is contemplated in a patient with a previously detected breast cancer. Although disturbances such as galactorrhea, amenorrhea, gynecomastia, and impotence have been reported, the clinical significance of elevated serum prolactin levels is unknown for most patients. An increase in mammary neoplasms has been found in rodents after chronic administration of antipsychotic drugs. Published epidemiologic studies have shown inconsistent results when exploring the association between hyperprolactinemia and breast cancer.

Other medicines and interactions

Hepatic microsomal enzyme inducing agents, such as carbamazepine, were found to significantly increase the clearance of thiothixene. Patients receiving these drugs should be observed for signs of reduced thiothixene effectiveness 4,5.

Due to a possible additive effect with hypotensive agents, patients receiving these drugs should be observed closely for signs of excessive hypotension when thiothixene is added to their drug regimen 6.