trifluoperazine hydrochloride

Action

Unknown. Thought to act on subcortical levels of hypothalamic and limbic systems by producing antidopaminergic effects. Also lowers seizure threshold and exhibits some adrenergic, muscarinic, and anticholinergic activity.

Availability

Tablets: 1 mg, 2 mg, 5 mg, 10 mg

Indications and dosages

➣ Schizophrenia

Adults: 2 to 5 mg P.O. b.i.d.; may increase gradually to obtain adequate response. Usual maintenance dosage is 15 to 20 mg/day.

Children ages 6 to 12: Initially, 1 mg P.O. once or twice daily in hospitalized patients or those under close supervision; may increase gradually up to 15 mg/day P.O. until symptoms are controlled or adverse reactions are intolerable.

➣ Nonpsychotic anxiety

Adults: 1 to 2 mg P.O. b.i.d. Do not exceed 6 mg/day or 12 weeks' duration.

Dosage adjustment

• Hepatic disease

• Elderly or debilitated patients

Contraindications

• Hypersensitivity to drug, other phenothiazines, or bisulfites

• Severe hepatic disease

• Bone marrow depression

• Blood dyscrasias

• Coma

• Concomitant use of other CNS depressants in high doses

Precautions

Use cautiously in:

• seizure disorders, cardiovascular disorders, GI obstruction, glaucoma, retinopathy

• elderly or debilitated patients

• pregnant or breastfeeding patients.

Administration

• Be aware that dosage should be adjusted to needs of individual. Lowest effective dosage should always be used.

Adverse reactions

CNS: sedation, dizziness, drowsiness, insomnia, fatigue, extrapyramidal effects, tardive dyskinesia, neuroleptic malignant syndrome (NMS)

CV: tachycardia, hypotension, orthostatic hypotension, peripheral edema, prolonged QT interval, torsades de pointes

EENT: dry eyes, blurred vision, miosis, mydriasis, epithelial keratopathy, pigmentary retinopathy

GI: constipation, biliary stasis, dry mouth, anorexia, adynamic ileus

GU: urinary retention, glycosuria, amenorrhea, ejaculatory disorders, galactorrhea, gynecomastia

Hematologic: leukopenia, agranulocytosis

Hepatic: cholestatic jaundice

Musculoskeletal: muscle weakness

Skin: photosensitivity, altered pigmentation, erythema, rash

Other: mild fever, weight gain, allergic reaction

Interactions

Drug-drug. Alpha-adrenergic blockers: additive effect

Antacids containing aluminum: decreased trifluoperazine absorption

Anticholinergics, anticholinergic-like drugs (including antidepressants, antihistamines, disopyramide, other phenothiazines, quinidine): additive anticholinergic effects

Anticonvulsants: decreased seizure threshold

Antihistamines, CNS depressants, general anesthetics, opioids, sedative-hypnotics: additive CNS depression

Barbiturates: decreased blood levels of both drugs

Guanethidine: decreased antihypertensive effect

Lithium: increased risk of extrapyramidal reactions, disorientation, and unconsciousness

Oral anticoagulants: decreased anticoagulant effect

Phenytoin: interference with phenytoin metabolism, causing phenytoin toxicity

Propranolol: increased blood levels of both drugs

Thiazide diuretics: additive orthostatic hypotension

Drug-diagnostic tests. Hepatic enzymes: increased levels

Phenylketonuria test: false-positive result

Prolactin: increased level, causing interference with gonadotropin tests

Urine bilirubin: false-positive result

Drug-herbs. St. John's wort: increased risk of photosensitivity

Drug-behaviors. Alcohol use: additive CNS depression and hypotension

Sun exposure: increased risk of photosensitivity

Patient monitoring

• Monitor ECG and blood pressure. Watch closely for hypotension.

• Assess CBC (including platelet count) and liver function tests. Stay alert for signs and symptoms of hepatic damage and blood dyscrasias.

See Monitor neurologic status, especially for indications of NMS (unstable blood pressure, high fever, sweating, stupor, muscle rigidity, and autonomic dysfunction). Immediately discontinue drug if these symptoms occur.

• If signs and symptoms of tardive dyskinesia appear (repetitive, involuntary, purposeless movements, such as grimacing, tongue protrusion, lip smacking, and rapid eye blinking), consider discontinuing drug. However, some patients may require treatment despite presence of the syndrome.

Patient teaching

• Tell patient that drug's full effect usually occurs in 1 to 2 weeks.

• Instruct patient to move slowly when sitting up or standing, to avoid dizziness from sudden blood pressure drop.

See Teach patient to recognize and immediately report signs and symptoms of NMS and tardive dyskinesia.

• Caution patient to avoid driving and other hazardous activities until he knows how drug affects him.

• Tell patient to avoid alcohol and certain herbs.

• Advise patient to avoid sun exposure and to wear sunscreen and protective clothing when going outdoors.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, herbs, and behaviors mentioned above.