Compazine

Action

Exerts anticholinergic, CNS depressant, and antihistaminic effects. Depresses release of hypothalamic and hypophyseal hormones, decreases sensitivity of middle-ear labyrinth, and reduces conduction in vestibular-cerebellar pathways.

Availability

Capsules (extended-release, maleate): 10 mg, 15 mg, 30 mg

Injection (edisylate): 5 mg/ml

Oral solution (edisylate): 5 mg/5 ml

Suppositories: 2.5 mg, 5 mg, 25 mg

Tablets: 5 mg, 10 mg, 25 mg

Indications and dosages

➣ Nausea

Adults: 5 to 10 mg P.O. three to four times daily or 15 mg P.O. once daily or 10 mg P.O. (extended-release) b.i.d., up to 40 mg/day. Or 2.5 to 10 mg I.V., not to exceed 40 mg/day.

Children weighing 18 to 38 kg (40 to 85 lb): 2.5 mg P.O. or P.R. t.i.d. or 5 mg P.O. or P.R. b.i.d., not to exceed 15 mg/day

Children weighing 13.6 to 17.7 kg (30 to 39 lb): 2.5 mg P.O. or P.R. two or three times daily, not to exceed 10 mg/day

Children weighing 9 to 13 kg (20 to 29 lb): 2.5 mg P.O. or P.R. daily to b.i.d., not to exceed 7.5 mg/day

➣ Nausea and vomiting related to surgery

Adults: 5 to 10 mg I.V. 15 to 30 minutes before anesthesia induction, repeated once if necessary; or 5 to 10 mg I.M. 1 to 2 hours before anesthesia induction, repeated once in 30 minutes if necessary

➣ Schizophrenia

Adults and children older than age 12: For mild symptoms, 5 to 10 mg P.O. three to four times daily; for moderate to severe symptoms in hospitalized or supervised patients, 10 mg P.O. three to four times daily, increased p.r.n. q 2 to 3 days to 50 to 75 mg P.O. daily or up to 150 mg/day as tolerated p.r.n. for more severely disturbed patients. Or 10 to 20 mg I.M.; may repeat q 2 to 4 hours for up to four doses p.r.n.

Children ages 2 to 12: Initially, 2.5 mg P.O. or P.R. two or three times daily (maximum of 10 mg on day 1); then increase based on response. Don't exceed 25 mg/day for children ages 6 to 12 or 20 mg/day for children ages 2 to 5.

➣ Anxiety

Adults and children older than age 12: 5 mg P.O. three to four times daily; or 15 mg P.O. (extended-release) once daily or 10 mg P.O. (extended-release) q 12 hours; up to 20 mg/day for a maximum of 12 weeks

Off-label uses

• Migraine

Contraindications

• Hypersensitivity to drug or other phenothiazines

• Coma

• Concurrent use of large amounts of CNS depressants

• Pediatric surgery

• Children younger than age 2 or weighing less than 9 kg (20 lb)

Precautions

Use cautiously in:

• cardiovascular or hepatic disease, glaucoma, seizures

• anticipated exposure to extreme heat

• children with acute illness.

Administration

• For I.V. infusion, dilute 20 mg in 1 L of compatible I.V. solution, such as normal saline solution.

• Don't mix in same syringe with other drugs.

• Know that injection solution may cause contact dermatitis. Don't get it on hands or clothing.

☞ Give I.V. by slow infusion only. Don't give as bolus.

• Know that I.M. injection is not preferred because it can cause local irritation. However, if I.M. route is prescribed, inject deep into upper outer quadrant of gluteal area.

• Don't give by subcutaneous route.

• After desired response, switch to P.O. form as prescribed.

• When infusing I.V., watch for hypotension. Keep patient supine for 30 minutes after infusion.

Adverse reactions

CNS: sedation, extrapyramidal reactions, tardive dyskinesia, neuroleptic malignant syndrome

CV: orthostatic hypotension, ECG changes, tachycardia

EENT: blurred vision, lens opacities, pigmentary retinopathy, dry eyes

GI: constipation, ileus, dry mouth, anorexia

GU: pink or reddish-brown urine, urinary retention, galactorrhea

Hematologic: agranulocytosis, leukopenia

Hepatic: cholestatic jaundice, hepatitis Metabolic: hyperthermia

Skin: photosensitivity, pigmentation changes, rash

Other: allergic reactions

Interactions

Drug-drug. Anticonvulsants: reduced seizure threshold

Antineoplastics: masking of antineoplastic toxicity

CNS depressants (including antihistamines, anticholinergics, opioids, other phenothiazines, sedative-hypnotics): additive CNS depression

Guanethidine: inhibition of antihypertensive effects

Oral anticoagulants: decreased anticoagulant effect

Phenytoin: increased or decreased phenytoin blood level Propranolol: increased blood levels of both drugs

Thiazide diuretics: increased risk of orthostatic hypotension

Drug-diagnostic tests. Liver function tests: abnormal results

Phenylketonuria test: false-positive result

Drug-herbs. Betel nut: increased risk of extrapyramidal reactions

Evening primrose oil: increased risk of seizures

Kava: increased risk of drug-related adverse reactions

Drug-behaviors. Alcohol use: additive CNS depression

Patient monitoring

☞ Monitor neurologic status, especially for signs and symptoms of neuroleptic malignant syndrome (high fever, sweating, unstable blood pressure, stupor, muscle rigidity, and autonomic dysfunction).

• In long-term therapy, assess for other adverse CNS effects, including extrapyramidal symptoms and tardive dyskinesia.

• Monitor patient closely if he's receiving drug for nausea and vomiting associated with chemotherapy, because it may mask symptoms of chemotherapy toxicity.

• Evaluate CBC and liver function tests.

Patient teaching

• Instruct patient to dilute oral solution with tomato or fruit juice, milk, coffee, soda, tea, water, or soup.

☞ Teach patient to recognize and immediately report signs and symptoms of an allergic reaction or neuroleptic malignant syndrome.

• Inform patient about drug's other CNS effects. Tell him to contact prescriber if these occur.

• Caution patient to avoid driving and other hazardous activities until he knows how drug affects concentration, vision, alertness, and motor skills.

• Tell patient drug may turn urine pink or reddish brown.

• 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.