Paramax

Action

Blocks dopamine receptors by disrupting CNS chemoreceptor trigger zone, increasing peristalsis and promoting gastric emptying

Availability

Injection: 5 mg/ml

Solution: 5 mg/5 ml

Solution (concentrated): 10 mg/ml

Tablets: 5 mg, 10 mg

Tablets (orally disintegrating): 5 mg, 10 mg

Indications and dosages

➣ To prevent chemotherapy-induced vomiting

Adults: 1 to 2 mg/kg I.V. 30 minutes before chemotherapy, then q 2 hours for two doses, then q 3 hours for three additional doses

➣ To facilitate small-bowel intubation; radiologic examination when delayed gastric emptying interferes

Adults and children older than age 14: 10 mg I.V. as a single dose

Children ages 6 to 14: 2.5 to 5 mg I.V. as a single dose

Children younger than age 6: 0.1 mg/kg I.V. as a single dose

➣ Diabetic gastroparesis

Adults: 10 mg P.O. 30 minutes before meals and at bedtime for 2 to 8 weeks. If patient can't tolerate P.O. doses, give same dosage I.V. or I.M.

➣ Gastroesophageal reflux

Adults: 10 to 15 mg P.O. 30 minutes before meals and at bedtime for up to 12 weeks. For prevention, single dose of 20 mg (some patients may respond to doses as small as 5 mg).

➣ Prevention of postoperative nausea and vomiting

Adults: 10 to 20 mg I.M. near end of surgical procedure. Repeat dose q 4 to 6 hours, as needed.

Dosage adjustment

• Renal impairment

Off-label uses

• Hiccups

Contraindications

• Hypersensitivity to drug

• Pheochromocytoma

• Parkinson's disease

• Suspected GI obstruction, perforation, or hemorrhage

• History of seizure disorders

Precautions

Use cautiously in:

• diabetes mellitus, renal dysfunction

• history of depression

• elderly patients

• pregnant or breastfeeding patients

• children.

Administration

• Mix oral solution with water, juice, carbonated beverage, or semisolid food (such as applesauce or pudding) just before administration.

• Remove orally disintegrating tablets with dry hands immediately before administering. After removing, place tablet on patient's tongue, where it will dissolve in approximately 1 minute. Tell patient to swallow saliva.

• Give I.M. or direct I.V. without further dilution.

• Administer low doses (10 mg or less) by direct I.V. injection slowly over 2 minutes. (Rapid injection may cause intense anxiety and restlessness followed by drowsiness.)

• For I.V. infusion, dilute with 50 ml of 5% dextrose in 0.9% sodium chloride solution, 5% dextrose in 0.45% sodium chloride solution, or lactated Ringer's solution. Infuse over at least 15 minutes.

Adverse reactions

CNS: drowsiness, restlessness, anxiety, depression, irritability, fatigue, lassitude, insomnia, tardive dyskinesia, parkinsonian-like reactions, extrapyramidal reactions, akathisia, dystonia

CV: hypertension, hypotension, arrhythmias, neuroleptic malignant syndrome

GI: nausea, constipation, diarrhea, dry mouth

GU: gynecomastia

Interactions

Drug-drug. Anticholinergics, opioids: antagonism of metoclopramide's GI motility effect

Antidepressants, antihistamines, other CNS depressants (such as opioids, sedative-hypnotics): additive CNS depression

Cimetidine, digoxin: decreased blood levels of these drugs

General anesthestics: exaggerated hypotension

Haloperidol, phenothiazines: increased risk of extrapyramidal reactions

Levodopa: decreased metoclopramide efficacy

MAO inhibitors: increased catecholamine release

Drug-diagnostic tests. Aldosterone, prolactin: increased levels

Drug-behaviors. Alcohol use: increased blood alcohol level, increased CNS depression

Patient monitoring

• Monitor blood pressure during I.V. administration.

• Stay alert for depression and other adverse CNS effects.

See Watch for extrapyramidal reactions, which usually occur within first 24 to 48 hours of therapy. To reverse these symptoms, give diphenhydramine 50 mg I.M. or benztropine 1 to 2 mg I.M., as prescribed.

• Check for development of parkinsonian-like symptoms, which may occur within first 6 months of therapy and usually subside within 2 to 3 months after withdrawal.

See With long-term use, assess patient for tardive dyskinesia and discontinue drug if signs or symptoms of tardive dyskinesia develop. Avoid treatment for longer than 12 weeks in all but rare cases in which therapeutic benefit outweighs risk of developing tardive dyskinesia.

See Monitor patient closely for signs and symptoms of neuroleptic malignant syndrome (hyperthermia, muscle rigidity, altered consciousness, and evidence of autonomic instability [irregular pulse or blood pressure, tachycardia, diaphoresis, and cardiac arrhythmias]); immediately discontinue drug if these symptoms occur.

• In diabetic patient, stay alert for gastric stasis. Insulin dosage may need to be adjusted.

Patient teaching

• Tell patient to take 30 minutes before meals.

• Tell patient taking orally disintegrating tablets to remove tablet with dry hands immediately before use. Instruct patient to place tablet on tongue, where it will dissolve in approximately 1 minute, and then swallow saliva.

See Instruct patient to report involuntary movements of face, eyes, or limbs; muscle rigidity; altered consciousness; irregular pulse or blood pressure; rapid or irregular heartbeats; or excessive sweating.

• Caution patient to avoid driving and other hazardous activities until drug's effects are known.

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