THIOTHIXENE HYDROCHLORIDE

THIOTHIXENE HYDROCHLORIDE (thye-oh-thix'een) Navane Classifications: psychotherapeutic; phenothiazine antipsychotic; Therapeutic: antipsychotic Prototype: Chlorpromazine Pregnancy Category: C

Availability

1 mg, 2 mg, 5 mg, 10 mg, 20 mg capsules; 5 mg/mL solution

Action

Xanthene derivative and a phenothiazine. Mechanism of antipsychotic effects is thought to be related to blockade of postsynaptic dopamine receptors in the brain.

Therapeutic Effect

Possesses antipsychotic, sedative, adrenolytic, and antiemetic activity.

Uses

Manifestations of psychotic disorders.

Unlabeled Uses

Antidepressant.

Contraindications

Hypersensitivity to thioxanthenes and phenothiazines; children <12 y; comatose states; CNS depression; circulatory collapse; blood dyscrasias; pregnancy (category C), lactation.

Cautious Use

History of convulsive disorders; alcohol withdrawal; glaucoma; prostatic hypertrophy; cardiovascular disease; patients who might be exposed to organophosphorus insecticides or to extreme heat; concomitant use of atropine or related drugs or ototoxic medications (especially ototoxic antibiotics); previously diagnosed breast cancer.

Route & Dosage

Psychotic Disorders Adult: PO 2 mg t.i.d., may increase up to 15 mg/d as needed or tolerated (max: 60 mg/d) IM 4 mg b.i.d. to q.i.d. (max: 30 mg/d) Dementia Behavior Geriatric: PO 1–2 mg 1–2 times/d, may increase q4–7d (max: 30 mg/d in divided doses)

Administration

Oral

• Avoid contact between oral concentrate and skin or clothing to prevent contact dermatitis. If concentrate spills, wash skin promptly with water.
• Give oral concentrate (contains 7% alcohol) diluted in a cupful of water, fruit juice, carbonated beverage, milk, or soup.
• Empty capsule and give with water or mix with food; useful if patient unable or unwilling to swallow the capsule.

Intramuscular

• Give IM injection deep into upper outer quadrant of buttock. Aspirate carefully before injection. Rotate injection sites.
• Do not permit access to more than one dose of medication if patient has suicidal tendency; supervise ingestion to prevent hoarding.
• Store at 15°–30° C (59°–86° F) in light-resistant containers unless otherwise indicated.

Adverse Effects (≥1%)

CNS: Drowsiness, insomnia, dizziness, cerebral edema, convulsions, extrapyramidal symptoms (dose related), paradoxical exaggeration of psychotic symptoms; sudden death, neuroleptic malignant syndrome, tardive dyskinesia, depressed cough reflex. GI: Xerostomia, constipation. CV: Tachycardia, orthostatic hypotension (especially with IM). Urogenital: Impotence, gynecomastia, galactorrhea, amenorrhea. Skin: Rash, contact dermatitis, photosensitivity. Special Senses: Blurred vision, pigmentary retinopathy. Metabolic: Decreased serum uric acid levels.

Interactions

Drug: Alcohol, anxiolytics, sedative-hypnotics, other cns depressants add to CNS depression; additive adverse effects with other phenothiazines; Herbal: Kava may increase risk and severity of dystonic reactions.

Pharmacokinetics

Absorption: Slowly absorbed from GI tract. Onset: Days to weeks PO; 1–6 h IM. Duration: Up to 12 h. Distribution: May remain in body for several weeks; crosses placenta. Metabolism: In liver. Elimination: In bile and feces. Half-Life: 34 h.

Nursing Implications

Assessment & Drug Effects

• Monitor for therapeutic response. Although therapeutic response can be observed 1–6 h following IM injection, it may be days or several weeks before there is a response with oral drug.
• Keep patient recumbent for at least 1 h following IM because of possibility of orthostatic hypotension. Check BP periodically.
• Monitor BP for excessive hypotensive response when thiothixene is added to drug regimen of patient on hypertensive treatment until therapy is stabilized.
• Monitor response when patient is changed from IM to PO forms (capsules, concentrate). Dosage adjustment may be necessary.
• Monitor infants delivered from mothers who have received thiothixene. Hyperreflexia has been reported.
• Lab tests: Periodic blood chemistry and liver function tests with prolonged therapy.
• Report extrapyramidal effects (pseudoparkinsonism, akathisia, dystonia) to physician; dose adjustment or short-term therapy with an antiparkinsonism agent may provide relief.
• Be alert to first symptoms of tardive dyskinesia (see Appendix F). Discontinue drug immediately and inform physician.

Patient & Family Education

• Make position changes slowly, particularly from lying down to upright because of danger of light-headedness; sit a few minutes before walking.
• Do not drive or engage in potentially hazardous activities until response to drug is known.
• Avoid alcohol and other depressants during therapy.
• Take drug as prescribed; do not alter dosing regimen or stop medication without consulting physician. Abrupt discontinuation can cause delirium.
• Do not use any OTC drugs without approval of physician.
• Note: Hyperhidrosis, while an uncomfortable adverse effect, does not indicate need to terminate therapy.
• Avoid excessive exposure to sunlight to prevent a photosensitivity reaction. If sun exposure is expected, protect skin with sunscreen lotion (SPF 12 or above).
• Schedule periodic eye exams and report blurred vision to physician.

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Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug