erythromycin

erythromycin

(er ith roe mye' sin)

erythromycin base

Oral, ophthalmic ointment, topical dermatologic solution for acne, topical dermatologic ointment:

Akne-mycin, A/T/S, Apo-Erythro (CAN), Diomycin (CAN), Erybid (CAN), Eryc, EryDerm, Erymax, Ery-Tab, Erythromycin Film-tabs,Ilotycin, PCE Dispertab

erythromycin estolate

erythromycin ethylsuccinate

Oral:

Apo-Erythro ES (CAN), E.E.S. 200, E.E.S. 400, E.E.S. Granules, EryPed, EryPed 200, EryPed 400, EryPed Drops

erythromycin gluceptate

Parenteral, IV:

Ilotycin Gluceptate

erythromycin lactobionate

Erythrocin I.V. (CAN), Erythrocin Lactobionate

erythromycin stearate

Apo-Erythro-S (CAN), Nu-Erythromycin-S (CAN)

Pregnancy Category B

Drug class

Macrolide antibiotic

Therapeutic actions

Bacteriostatic or bactericidal in susceptible bacteria; binds to cell membrane, causing change in protein function, leading to cell death.

Indications

Systemic administration

·        Acute infections caused by sensitive strains of Streptococcus pneumoniae, Mycoplasma pneumoniae, Listeria monocytogenes, Legionella pneumophila

·        URIs, lower respiratory tract infections, skin and soft-tissue infections caused by group A beta-hemolytic streptococci when oral treatment is preferred toinjectable benzathine penicillin

·        PID caused by N. gonorrhoeae in patients allergic to penicillin

·        In conjunction with sulfonamides in URIs caused by Haemophilus influenzae

·        As an adjunct to antitoxin in infections caused by Corynebacterium diphtheriae and Corynebacterium minutissimum

·        Prophylaxis against alpha-hemolytic streptococcal endocarditis before dental or other procedures in patients allergic to penicillin who have valvular heart disease

·        Oral erythromycin: Treatment of intestinal amebiasis caused by Entamoeba histolytica; infections in the newborn and in pregnancy that are caused byChlamydia trachomatis and in adult chlamydial infections when tetracycline cannot be used; primary syphilis (Treponema pallidum) in penicillin-allergic patients; eliminating Bordetella pertussis organisms from the nasopharynx of infected individuals and as prophylaxis in exposed and susceptible individuals

·        Unlabeled uses: Erythromycin base is used with neomycin before colorectal surgery to reduce wound infection; treatment of severe diarrhea associated withCampylobacter enteritis or enterocolitis; treatment of genital, inguinal, or anorectal lymphogranuloma venereum infection; treatment of Haemophilus ducreyi(chancroid)

Ophthalmic ointment

·        Treatment of superficial ocular infections caused by susceptible strains of microorganisms; prophylaxis of ophthalmia neonatorum caused by N. gonorrhoeaeor C. trachomatis

Topical dermatologic solutions for acne

·        Treatment of acne vulgaris

Topical dermatologic ointment

·        Prophylaxis against infection in minor skin abrasions

·        Treatment of skin infections caused by sensitive microorganisms

Contraindications and cautions

Systemic administration

·        Contraindicated with allergy to erythromycin.

·        Use cautiously with hepatic dysfunction, lactation (secreted and may be concentrated in breast milk; may modify bowel flora of nursing infant and interfere with fever workups).

Ophthalmic ointment

·        Contraindicated with allergy to erythromycin; viral, fungal, mycobacterial infections of the eye.

Available forms

Base: Tablets—250, 333, 500 mg; DR capsules—250 mg; ophthalmic ointment—5 mg/g. Estolate: Tablets—500 mg; capsules—250 mg; suspension—125, 250 mg/5 mL. Stearate tablets—250, 500 mg ethylsuccinate: Ethylsuccinate tablets—200, 400 mg; suspension—200, 400 mg/5 mL, 100 mg/2–5 mL; powder for suspension—200 mg/5 mL; granules for suspension—400 mg/5 mL; topical solution—1.5%, 2%; topical gel, ointment—2%. Lactobionate injection: 500, 1,000 mg.

Dosages

Systemic administration

Oral preparations of the different erythromycin salts differ in pharmacokinetics: 400 mg erythromycin ethylsuccinate produces the same free erythromycin serum levels as 250 mg of erythromycin base, stearate, or estolate.

ADULTS

15–20 mg/kg/day in continuous IV infusion or up to 4 g/day in divided doses q 6 hr; 250 mg (400 mg of ethylsuccinate) q 6 hr PO or 500 mg q 12 hr PO or 333 mg q 8 hr PO, up to 4 g/day, depending on the severity of the infection.

·        Streptococcal infections: 20–50 mg/kg/day PO in divided doses (for group A beta-hemolytic streptococcal infections, continue therapy for at least 10 days).

·        Legionnaire's disease: 1–4 g/day PO or IV in divided doses for 10–21 days (ethylsuccinate 1.6 g/day; optimal doses not established).

·        Dysenteric amebiasis: 250 mg (400 mg of ethylsuccinate) PO qid or 333 mg q 8 hr for 10–14 days.

·        Acute PID (N. gonorrhoeae): 500 mg of lactobionate or gluceptate IV q 6 hr for 3 days and then 250 mg stearate or base PO q 6 hr or 333 mg q 8 hr for 7 days.

·        Prophylaxis against bacterial endocarditis before dental or upper respiratory procedures: 1 g (1.6 g of ethylsuccinate) 2 hr before procedure and 500 mg (800 mg ethylsuccinate) 6 hr later.

·        Chlamydial infections: Urogenital infections during pregnancy: 500 mg PO qid or 666 mg q 8 hr for at least 7 days, one-half this dose q 8 hr for at least 14 days if intolerant to first regimen. Urethritis in males: 800 mg of ethylsuccinate PO tid for 7 days.

·        Primary syphilis: 30–40 g (48–64 g of ethylsuccinate) in divided doses over 10–15 days.

·        CDC recommendations for STDs: 500 mg PO qid for 7–30 days, depending on the infection.

PEDIATRIC PATIENTS

30–50 mg/kg/day PO in divided doses. Specific dosage determined by severity of infection, age, and weight.

·        Dysenteric amebiasis: 30–50 mg/kg/day in divided doses for 10–14 days.

·        Pertussis: 1 g PO daily in divided doses for 14 days.

·        Prophylaxis against bacterial endocarditis: 20 mg/kg before procedure and then 10 mg/kg 6 hr later.

·        Chlamydial infections: 50 mg/kg/day PO in divided doses, for at least 2 (conjunctivitis of newborn) or 3 (pneumonia of infancy) wk.

Ophthalmic ointment

ADULTS AND PEDIATRIC PATIENTS

One-half–inch ribbon instilled into conjunctival sac of affected eye two to six times per day, depending on severity of infection.

Topical

ADULTS AND PEDIATRIC PATIENTS

·        Dermatologic solution for acne: Apply to affected areas morning and evening.

·        Topical dermatologic ointment: Apply to affected area one to five times per day.

Pharmacokinetics

Route	Onset	Peak
Oral	1–2 hr	1–4 hr
IV	Rapid	1 hr

Metabolism: Hepatic; T_1/2: 1.5–2 hr

Distribution: Crosses placenta; enters breast milk

Excretion: Bile, urine

IV facts

Preparation: Reconstitute powder for IV infusion only with sterile water for injection without preservatives—10 mL for 250- and 500-mg vials, 20 mL for 1-g vials. Prepare intermittent infusion as follows: Dilute 250–500 mg in 100–250 mL of 0.9% sodium chloride injection or D₅W. Prepare for continuous infusion by adding reconstituted drug to 0.9% sodium chloride injection, lactated Ringer's injection, or D₅W that will make a solution of 1 g/L.

Infusion: Intermittent infusion: Administer over 20–60 min qid; infuse slowly to avoid vein irritation. Administer continuous infusion within 4 hr, or buffer the solution to neutrality if administration is prolonged.

Incompatibilities: Gluceptate—do not add to aminophylline, oxytetracycline, pentobarbital, secobarbital, tetracycline. Lactobionate—do not mix withcephalothin, heparin, metoclopramide, tetracycline.

Y-site incompatibilities: Avoid chloramphenicol, heparin, phenobarbital, phenytoin.

Adverse effects

Systemic administration

·        CNS: Reversible hearing loss, confusion, uncontrollable emotions, abnormal thinking

·        CV: Ventricular arrhythmias (with IV)

·        GI: Abdominal cramping, anorexia, diarrhea, vomiting, pseudomembranous colitis, hepatotoxicity

·        Hypersensitivity: Allergic reactions ranging from rash to anaphylaxis

·        Other: Superinfections

Ophthalmic ointment

·        Dermatologic: Edema, urticaria, dermatitis, angioneurotic edema

·        Local: Irritation, burning, itching at site of application

Topical dermatologic preparations

·        Local: Superinfections, particularly with long-term use

Interactions

Systemic administration

Drug-drug

·        Increased serum levels of digoxin

·        Increased effects of oral anticoagulants, theophyllines, carbamazepine, ergot derivatives, disopyramide, calcium blockers, HMG-CoA reductase inhibitors, midazolam, proton pump inhibitors, quinidine

·        Increased therapeutic and toxic effects of corticosteroids

·        Increased levels of cyclosporine and risk of renal toxicity

Drug-food

·        Decreased metabolism and increased risk of toxic effects if taken with grapefruit juice; avoid this combination

Drug-lab test

·        Decreased urinary estriol levels due to inhibition of hydrolysis of steroids in the gut

·        Interferes with fluorometric determination of urinary catecholamines

Topical dermatologic solution for acne

Drug-drug

·        Increased irritant effects with peeling, desquamating, or abrasive agents

Nursing considerations

Assessment

·        History: Allergy to erythromycin, hepatic dysfunction, lactation; viral, fungal, mycobacterial infections of the eye (ophthalmologic), pregnancy

·        Physical: Site of infection; skin color, lesions; orientation, affect, hearing tests; R, adventitious sounds; GI output, bowel sounds, liver evaluation; culture and sensitivity tests of infection, urinalysis, LFTs

Interventions

Systemic administration

·        Culture site of infection before therapy.

·        Administer oral erythromycin base or stearate on an empty stomach, 1 hr before or 2–3 hr after meals, with a full glass of water (oral erythromycin estolate,ethylsuccinate, and certain enteric-coated tablets [see manufacturer's instructions] may be given without regard to meals).

·        Administer around the clock to maximize effect; adjust schedule to minimize sleep disruption.

·        Monitor liver function in patients on prolonged therapy.

·        Give some preparations (see above) with meals, or substitute one of these preparations, if GI upset occurs with oral therapy.

Topical dermatologic solution for acne

·        Wash affected area, rinse well, and dry before application.

Ophthalmic and topical dermatologic preparation

·        Use topical products only when needed. Sensitization produced by the topical use of an antibiotic may preclude its later systemic use in serious infections. Topical antibiotic preparations not normally used systemically are best.

·        Culture site before beginning therapy.

·        Cover the affected area with a sterile bandage if needed (topical).

Teaching points

Systemic administration

·        Take oral drug on an empty stomach, 1 hour before or 2–3 hours after meals, with a full glass of water; some forms may be taken without regard to meals. Do not drink grapefruit juice while on this drug. The drug should be taken around the clock; schedule to minimize sleep disruption. Finish the full course of the drug therapy.

·        You may experience these side effects: Stomach cramping, discomfort (take the drug with meals, if appropriate); uncontrollable emotions, crying, laughing, abnormal thinking (reversible).

·        Report severe or watery diarrhea, severe nausea or vomiting, dark urine, yellowing of the skin or eyes, loss of hearing, rash or itching.

Ophthalmic ointment

·        Pull the lower eyelid down gently and squeeze a one-half–inch ribbon of the ointment into the sac, avoid touching the eye or lid. A mirror may be helpful. Gently close the eye, and roll the eyeball in all directions.

·        Drug may cause temporary blurring of vision, stinging, or itching.

·        Report stinging or itching that becomes pronounced.

Topical dermatologic solution for acne

·        Wash and rinse area, and pat it dry before applying solution.

·        Use fingertips or an applicator to apply; wash hands thoroughly after application.

Adverse effects in Italic are most common; those in Bold are life-threatening.