LOXAPINE HYDROCHLORIDE

LOXAPINE HYDROCHLORIDE
(lox'a-peen)
Loxitane C, Loxitane IM
LOXAPINE SUCCINATE
Loxitane, Loxapac

Classifications: psychotherapeutic; antipsychotic;
Therapeutic: antipsychotic
Prototype: Chlorpromazine
Pregnancy Category: C

Availability

5 mg, 10 mg, 25 mg, 50 mg capsules; 25 mg/mL oral solution; 50 mg/mL injection

Action

This antipsychotic blocks postsynaptic dopamine receptors in limbic system and increases dopamine turnover by blockade of D₂-receptors in that region. After approximately 12 wk of chronic therapy, depolarization blockade of dopamine occurs, decreasing dopamine neurotransmission, correlating with its antipsychotic effects. D₂-receptor blockade is also responsible for the potent extrapyramidal effects observed with use of this drug. Dopamine blockade in the chemoreceptor trigger zone is responsible for antiemetic effects of the drug.

Therapeutic Effect

Stabilizes emotional component of schizophrenia by acting on subcortical level of CNS.

Uses

Manifestations of psychotic disorders.

Unlabeled Uses

Anxiety associated with mental depression.

Contraindications

Severe drug-induced CNS depression; Parkinson's disease; comatose states, children <16 y; pregnancy (category C), lactation.

Cautious Use

Glaucoma, prostatic hypertrophy, urinary retention, history of convulsive disorders, cardiovascular disease; alcoholism; brain tumor; older adults; hematologic disease; hepatic disease; peptic ulcer disease; renal impairment; thyroid disease.

Route & Dosage

Psychosis
Adult: PO Start with 10 mg b.i.d. and rapidly increase to maintenance levels of 60–100 mg/d in 2–4 divided doses (max: 250 mg/d) IM 12.5–50 mg q4–6h

Dementia Behavior
Geriatric: PO 5–10 mg 1–2 times/d, may increase q4–7d (max: 125 mg/d)

Administration

Oral

Give with food, milk, or water to reduce possibility of stomach irritation.
Dilute oral concentrate in about 2–3 oz (60–90 mL) water or orange or grapefruit juice shortly before administration. Measure concentrate with calibrated dropper dispensed with drug. Do not store diluted solution.

Intramuscular

Use only with acute psychosis or when oral route not feasible.
Reduce dosage gradually over period of several days when therapy is to be terminated.
Protect from light and freezing. Intensification of straw color to light amber is acceptable. Discard if solution is noticeably discolored.

Adverse Effects (≥1%)

CNS: Drowsiness, sedation, dizziness, syncope, EEG changes, paresthesias, staggering gait, muscle weakness, extrapyramidal effects, akathisia, tardive dyskinesia, neuroleptic malignant syndrome. CV: Orthostatic hypotension, hypertension, tachycardia. Special Senses: Nasal congestion, tinnitus; blurred vision, ptosis. GI: Constipation, dry mouth. Skin: Dermatitis, facial edema, pruritus, photosensitivity. Urogenital: Urinary retention, menstrual irregularities. Body as a Whole: Polydipsia, weight gain or loss, hyperpyrexia, transient leukopenia.

Interactions

Drug: Alcohol and other cns depressants potentiate CNS depression; will inhibit vasopressor effects of epinephrine.

Pharmacokinetics

Absorption: Readily absorbed from GI tract. Onset: 20–30 min. Peak: 1.5–3 h. Duration: 12 h. Distribution: Widely distributed; crosses placenta; distributed into breast milk. Metabolism: In liver. Elimination: 50% in urine, 50% in feces. Half-Life: 19 h.

Nursing Implications

Assessment & Drug Effects

Monitor baseline BP pattern prior and during therapy; both hypotension and hypertension have been reported as adverse reactions.
Observe carefully for extrapyramidal effects such as acute dystonia (see Appendix F) during early therapy. Most symptoms disappear with dose adjustment or with antiparkinsonism drug therapy.
Discontinue therapy and report promptly to physician the first signs of impending tardive dyskinesia (fine vermicular movements of the tongue) when patient is on long-term treatment.
Monitor I&O and bowel elimination patterns and check for bladder distention. Depressed patients often fails to report urinary retention or constipation.
Risk of seizures is increased in those with history of convulsive disorders.

Patient & Family Education

Do NOT change dosage regimen in any way without physician approval.
Avoid self-dosing with OTC drugs unless approved by the physician.
Drowsiness usually decreases with continued therapy. If it persists and interferes with daily activities, consult physician. A change in time of administration or dose may help.
Avoid potentially hazardous activity until response to drug is known.
Learn measures to relieve dry mouth; rinse mouth frequently with water, suck hard candy. Avoid commercial products that may contain alcohol and enhance drying and irritation.
Notify physician of blurred or colored vision.
Do not take drug dose and notify physician of following: Light-colored stools, bruising, unexplained bleeding, prolonged constipation, tremor, restlessness and excitement, sore throat and fever, rash.
Stay out of bright sun; cover exposed skin with sunscreen.

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

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