Erythromycin Ethylsuccinate/Sulfisoxazole

A to Z Drug Facts

 Action Erythromycin suppresses bacterial protein synthesis; sulfonamides interfere with bacterial folic acid synthesis.

 Indications Treatment of acute otitis media in children caused by susceptible strains of Haemophilus influenzae.

 Contraindications Hypersensitivity to chemically related drugs (sulfonylureas, thiazide and loop diuretics, carbonic anhydrase inhibitors, sunscreens containing PABA, local anesthetics) or salicylates; patients taking terfenadine or astemizole; porphyria; use in infants < 20 mo, pregnant women at term and women nursing infants < 2 mo.

 Route/Dosage

CHILDREN: PO 50 mg/kg/day erythromycin and 150 mg/kg/day (maximum 6 gm/day) sulfisoxazole in equally divided doses qid for 10 days.

 Interactions

Anticoagulants: May increase anticoagulant effects. Antihistamines, non-sedating (eg, astemizole, terfenadine): Erythromycin significantly alters metabolism of terfenadine. Rare cases of serious cardiovascular events including death have been reported. Astemizole, bromocriptine, carbamazepine, disopyramide, hexobarbital, methylprednisolone, phenytoin: May cause decreased metabolism and increased concentrations of these drugs. Cyclosporine: Erythromycin may interfere with metabolism while sulfonamides may decrease cyclosporine levels; both increase risk of nephrotoxicity. Digoxin: May increase digoxin levels. Lovastatin: Severe myopathy or rhabdomyolysis may occur. Methotrexate: Sulfonamides can displace methotrexate from protein-binding sites and increase free methotrexate levels. Sulfonylureas: Sulfisoxazole may potentiate hypoglycemic effects. Theophyllines: May increase theophylline plasma concentrations. Thiopental: May enhance anesthetic effects of thiopental.

 Lab Test Interferences Sulfosalicylic acid turbidity test for urinary protein: Sulfisoxazole may produce false-positive results. Urinary glucose test: Sulfonamides may produce false-positive results when performed by Benedict's method. Urobilistix test: Sulfisoxazole may interfere with test results.

 Adverse Reactions

CNS: Headache; peripheral neuropathy; dizziness; psychosis; hallucinations; depression; convulsions. DERM: Urticaria; skin eruptions; pruritus; photosensitivity; anaphylaxis; erythema multiforme; toxic epidermal necrolysis; exfoliative dermatitis; angioedema; arteritis; vasculitis. EENT: Hearing loss (associated with high doses erythromycin and renal insufficiency). GI: Nausea; vomiting; abdominal pain/cramping; diarrhea; anorexia. GU: Crystalluria; hematuria; increased BUN and creatinine; nephritis; toxic nephrosis with oliguria. HEPA: Hepatic dysfunction; abnormal liver function test results; pseudomembranous colitis; GI hemorrhage; pancreatitis. HEMA: Leukopenia; agranulocytosis; aplastic anemia; thrombocytopenia; hemolytic anemia; purpura; eosinophilia; clotting disorders; methemoglobinemia. OTHER: Fever; chills; arthralgias; myalgias; periarteritis nodosum; systemic lupus erythematosus; serum sickness.

 Precautions

Pregnancy: Category C. Lactation: Both erythromycin and sulfisoxazole are excreted in breast milk. Children: Children < 2 mo should not be exposed (directly or through breast milk) to sulfonamides because of risk of kernicterus. Special risk patients: May aggravate weakness in patients with myasthenia gravis. Use drug with caution in patients with severe allergies or bronchial asthma. Dose-related hemolytic anemia may occur in patients with G-6-PD deficiency. Fatalities: Rare fatalities from severe reactions associated with hypersensitivity, agranulocytosis, aplastic anemia, blood dyscrasias, renal and hepatic damage, irreversible neuromuscular and CNS changes and fibrosing alveolitis have been reported with sulfonamides. Hepatic or renal impairment: Use drug with caution in patients with renal or hepatic impairment. Hepatotoxicity has been associated with erythromycin. Ototoxicity: May occur, especially in patients with renal or hepatic insufficiency and elderly patients and with administration of large doses. Pseudomembranous colitis: Consider possibility in patients with diarrhea. Superinfection: Prolonged use may result in bacterial or fungal overgrowth of nonsusceptible microorganisms.

 Administration/Storage

• Give with full glass of water 1 hr before or 2 hr after meals.
• If GI upset is significant, administer with food or milk.
• Shake oral suspension well. Refrigerate after opening. Discard unused portion after 14 days.

 Assessment/Interventions

• Obtain patient history, including drug history and any known allergies. Note any hypersensitivity to erythromycin or macrolide antibiotics and history of liver disease, fungal disease or colic.
• Obtain baseline CBC, BUN, creatinine and liver function tests and monitor throughout therapy.
• Obtain culture and sensitivity before instituting drug regimen.
• Monitor for diarrhea, nausea, vomiting and abdominal discomfort. If severe, contact physician.
• Monitor I&O. Encourage oral intake of fluids.
• Monitor for signs and symptoms of superinfection: perianal irritation, black furry tongue or vaginal discharge.
• Notify physician of tachycardia, palpitations, syncope, cyanosis, seizures and hallucinations or any change in hearing.
• Notify physician if urticaria or anemia occur.

 Patient/Family Education

• Instruct patient/family to follow complete course of therapy.
• Advise patient to shake suspension well before using and refrigerate after opening.
• Tell patient to take drug with full glass of water 1 hr before or 2 hr after meals. If GI distress occurs, take with food or milk.
• Instruct patient to report these symptoms to physician: tachycardia, palpitations, syncope, cyanosis, seizures, hallucinations, shortness of breath, rash, bleeding, diarrhea, inability to void, urticaria, abdominal pain or signs of superinfection.
• Caution patient to avoid exposure to sunlight and to use sunscreen or wear protective clothing to avoid photosensitivity reaction.
• Instruct patient not to take otc medications without consulting physician.

Books@Ovid
Copyright © 2003 Facts and Comparisons
David S. Tatro
A to Z Drug Facts