loxapine succinate

Action

Unknown. Thought to block neurotransmission of postsynaptic dopamine receptors in brain, alleviating psychotic symptoms.

Availability

Capsules: 5 mg, 10 mg, 25 mg, 50 mg

Indications and dosages

➣ Schizophrenia

Adults: 10 mg P.O. b.i.d. Dosage may be increased over first 7 to 10 days, up to 100 mg/day P.O. in two to four divided doses. Maximum dosage is 250 mg/day.

Dosage adjustment

• Elderly patients

Contraindications

• Hypersensitivity to drug or other dibenzoxazepines

• Coma or severe drug-induced CNS depression

Precautions

Use cautiously in:

• seizures, cerebral arteriosclerosis, severe hypotension, hypertension, glaucoma, breast cancer, hepatic disease, bone marrow depression, Parkinson's disease, blood dyscrasias, urinary retention, concurrent use of other CNS active drugs or anticholinergics

• pregnant or breastfeeding patients

• children younger than age 16.

Administration

• Give with or without food.

Adverse reactions

CNS: drowsiness, insomnia, vertigo, headache, dizziness, weakness, akinesia, staggering or shuffling gait, slurred speech, agitation, extrapyramidal reactions, sedation, syncope, tardive dyskinesia, numbness, confusion, pseudoparkinsonism, EEG changes, seizures, neuroleptic malignant syndrome

CV: orthostatic hypotension, hypertension, ECG changes

EENT: blurred vision, ptosis, nasal congestion

GI: nausea, vomiting, constipation, dry mouth, paralytic ileus

GU: urinary retention

Hematologic: leukopenia, agranulocytosis, thrombocytopenia

Hepatic: hepatocellular injury with hepatic enzyme elevations

Metabolic: polydipsia

Musculoskeletal: muscle twitching

Skin: rash, pruritus, seborrhea, photosensitivity, alopecia

Other: weight gain or loss, hyperpyrexia, facial edema, hypersensitivity reactions

Interactions

Drug-drug. Anticholinergics, CNS depressants: additive effects

Epinephrine: severe hypotension, tachycardia, decreased epinephrine effects

Drug-diagnostic tests. Granulocytes, platelets, white blood cells: decreased counts

Liver function tests: increased values

Drug-behaviors. Alcohol use: increased CNS depression

Patient monitoring

• Measure blood pressure before and periodically during therapy.

• Monitor hematologic studies and liver function tests.

See Stay alert for evidence of neuroleptic malignant syndrome (extrapyramidal symptoms, hyperpyrexia, muscle rigidity, altered mental status, irregular pulse or blood pressure, tachycardia, arrhythmias, diaphoresis).

• Assess for tardive dyskinesia (involuntary jerky movements of face, tongue, jaws, trunk, arms, and legs), especially in elderly women.

Patient teaching

• Tell patient to take with or without food.

• Inform patient that drug may cause tardive dyskinesia. Describe symptoms.

• Caution patient to avoid activities requiring mental concentration until drug's effects are known.

See Teach patient to immediately report sore throat, fever, rash, impaired vision, tremors, involuntary muscle twitching, muscle stiffness, or yellowing of eyes or skin.

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

• Caution patient to avoid alcohol use.

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