Thiothixene (Thiothixene)

Overview

Mechanism of Action

DESCRIPTION Thiothixene is a thioxanthene derivative. Specifically, it is the cis isomer of N,N-dimethyl-9-[3-(4- methyl-1-piperazinyl)propylidene]thioxanthene-2-sulfonamide. It may be represented by the following structural formula The thioxanthenes differ from the phenothiazines by the replacement of nitrogen in the central ring with a carbon-linked side chain fixed in space in a rigid structural configuration. An N,N-dimethyl sulfonamide functional group is bonded to the thioxanthene nucleus. Each capsule contains 1 mg, 2 mg, 5 mg or 10 mg of thiothixene, USP and the following inactive ingredients: colloidal silicon dioxide, croscarmellose sodium, lactose monohydrate, magnesium stearate, microcrystalline cellulose, pregelatinized starch and sodium lauryl sulfate.

Indications

INDICATIONS & USAGE 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.

Common Doses

2 mg
15 mg
5 mg
20 mg

Dosage

DOSAGE & ADMINISTRATION 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 capsule 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.

Black Box Warning

BOXED WARNING WARNING Increased Mortality in Elderly Patients with Dementia-Related Psychosis : Elderly patients with dementia-related psychosis treated with antipsychotic drugs are at an increased risk of death. Analyses of seventeen placebo-controlled trials (modal duration of 10 weeks), largely in patients taking atypical antipsychotic drugs, revealed a risk of death in drug-treated patients of between 1.6 to 1.7 times the risk of death in placebo-treated patients. Over the course of a typical 10-week controlled trial, the rate of death in drug-treated patients was about 4.

Contraindications

CONTRAINDICATIONS Thiothixene capsules are contraindicated in patients with circulatory collapse, comatose states, central nervous system depression due to any cause, and blood dyscrasias. Thiothixene is 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.

Side Effects

ADVERSE REACTIONS 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. Cardiovascular Effects Tachycardia, hypotension, light-headedness, and syncope. In the event hypotension occurs, epinephrine should not be used as a pressor agent since a paradoxical further lowering of blood pressure may result.

Interactions

DRUG 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 .