Erythromycin

Erythromycin

[1 vial $8.22; 500mg tablets 44 cents]

ADMINISTRATION ROUTES:

  • PO, NG, IV

ALTERNATIVE NAMES:

  • E-mycin

ICU INDICATIONS:

  1. Empirical treatment of atypical pneumonia
  2. Treatment of infections caused by other susceptible organisms
  3. gutprokinetic

PRESENTATION AND ADMINISTRATION:

  • PO:
    E-Mycin 400mg tablets (pink), E-Mycin 200 Suspension 200mg/5ml (pink), E-Mycin 400 Suspension 400mg/5ml (pink), ERA 250mg tablets (white), ERA 500mg tablets (white)
  • IV:
    1gm vial of powder
    Add 20ml of water for injection ONLY to 1gm vial
    Shake until all of the powder is dissolved (concentration = 50mg/ml). Expected time for dissolution is 4 minutes of shaking. Add required dose to compatible IV fluid to give a concentration between 1mg/ml and 5mg/ml (when erythromycin being administered through a central line in ICU 5mg/ml is usually appropriate)

Administer over 60 minutes. For patients with high risk of cardiac arrhythmia infusion should be administered over 2 hours.
Risk factors for cardiac arrhythmia due to erythromycin are as follows:
– history of cardiac disease
– long QT syndrome
– quinidine, procainamide or disopyramide
– impaired hepatic metabolism
– hypokalaemia or hypomagnesaemia
Compatible with the following IV fluids:
Normal saline, Hartmanns
Reconstituted solution containing 50mg/ml is stable for 24 hours at room temperature. When further diluted with saline or Hartmanns, solutions should be used within 8 hours.

Final Volume

Amount of Erythromycin

Final Concentration

100ml

500mg

5mg/ml

250ml

500mg

2mg/ml

500ml

500mg

1mg/ml

200ml

1000mg

5mg/ml

250ml

1000mg

4mg/ml

500ml

1000mg

2mg/ml

100ml

1000mg

1mg/ml

DOSAGE:

  • IV:
    For infections requiring intensive care the usual dose is 1gm 6 hourly For use as a prokinetic 125mg-250mg 6 hourly is usually appropriate
  • PO:
    500mg 6 hourly.

DOSAGE IN RENAL FAILURE AND RENAL REPLACEMENT THERAPY:

  • Dose in renal impairment [GFR (ml/min)]
    <10: 50% of normal dose
    10-20: 50% of normal dose
    >20-50: dose as in normal renal function
  • Dose in renal replacement therapy
    CAPD: 50% of normal dose
    HD: dose as in normal renal function
    CVVHDF: dose as in normal renal function

DOSAGE IN PAEDIATRICS:

  • IV/ PO:
    For infections requiring intensive care 15-25mg/kg 6 hourly
    For use as a prokinetic 2mg/kg 8 hourly

CLINICAL PHARMACOLOGY:

  • Erythromycin belongs to the macrolide group of antibiotics. Erythromycin acts by inhibition of protein synthesis in susceptible organisms by reversibly binding to 50 S ribosomal subunits, thereby inhibiting translocation of aminoacyl transfer-RNA and inhibiting polypeptide synthesis.
  • Erythromycin is usually active against the following organisms in vitro and in clinical infections:
    Streptococcus
    pyogenes (group A Beta-hemolytic streptococci), Alpha-hemolytic streptococci (viridans group), Staphylococcus aureus (resistant organisms may emerge during treatment), Streptococcus pneumoniae, Mycoplasma pneumoniae, Treponema pallidum, Corynebacterium diphtheriae, Corynebacterium minutissimum, Entamoeba histolytica, Listeria monocytogenes, Neisseria gonorrhoeae, Bordetella pertussis, Legionella pneumophila (agent of Legionnaires’ disease), Ureaplasma urealyticum, Chlamydia trachomatis.

CONTRAINDICATIONS:

  1. hypersensitivity to erythromycin

WARNINGS

  • Hepatic dysfunction:
    There have been reports of hepatic dysfunction, including increased liver enzymes, and hepatocellular and/or cholestatic hepatitis, with or without jaundice, occurring in patients receiving oral erythromycin products.
  • Pseudomembranous colitis:
    Pseudomembranous colitis has been reported with nearly all antibacterial agents, including erythromycin, and may range in severity from mild to life threatening. Therefore, it is important to consider this diagnosis in patients who present with diarrhea subsequent to the administration of antibacterial agents.

PRECAUTIONS

  • General:
    There have been reports that erythromycin may aggravate the weakness of patients with myasthenia gravis.
  • Laboratory Tests:
    No tests in addition to routine ICU tests are indicated
  • Drug/Laboratory Test Interactions:
    Erythromycin interferes with the fluorometric determination of urinary catecholamines.

IMPORTANT DRUG INTERACTIONS FOR THE ICU

  • Erythromycin use in patients who are receiving high doses of theophylline may be associated with an increase in serum theophylline levels and potential theophylline toxicity. In case of theophylline toxicity and/or elevated serum theophylline levels, the dose of theophylline should be reduced while the patient is receiving concomitant erythromycin therapy. Concomitant administration of erythromycin and digoxin has been reported to result in elevated digoxin serum levels. There have been reports of increased anticoagulant effects when erythromycin and oral anticoagulants were used concomitantly. Increased anticoagulation effects due to interactions of erythromycin with various oral anticoagulents may be more pronounced in the elderly. Erythromycin has been reported to decrease the clearance of triazolam and midazolam and thus may increase the pharmacologic effect of these benzodiazepines. The use of erythromycin in patients concurrently taking drugs metabolized by the cytochrome P450 system may be associated with elevations in serum levels of these other drugs. There have been reports of interactions of erythromycin with carbamazepine, cyclosporine, tacrolimus, hexobarbital, phenytoin, alfentanil, cisapride, disopyramide, lovastatin, bromocriptine, valproate, terfenadine, and astemizole. Serum concentrations of drugs metabolized by the cytochrome P450 system should be monitored closely in patients concurrently receiving erythromycin.

ADVERSE REACTIONS

  • Body as a Whole:
    Anaphylaxis
  • Gastrointestinal System:
    Nausea, vomiting, abdominal pain, diarrhoea and anorexia. Symptoms of hepatitis, hepatic dysfunction and/or abnormal liver function test results may occur
  • Cardiovascular System:
    Rarely, erythromycin has been associated with the production of ventricular arrhythmias, including ventricular tachycardia and torsades de pointes, in individuals with prolonged QT intervals.
    Local:

    thrombophlebitis

Critical Care Drug Manual

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