(di-rith-roe-mye-sin) ,


(trade name)


Therapeutic: anti infectives
Pharmacologic: macrolides
Pregnancy Category: C


Treatment of the following infections:
  • Acute bacterial exacerbations of chronic bronchitis due to Haemophilis influenzae, Moraxella catarrhalis, or Streptococcus pneumoniae,
  • Secondary bacterial infections of acute bronchitis due to Moraxella catarrhalis or Streptococcus pneumoniae,
  • Community-acquired pneumonia due to Legionella pneumophila,Mycoplasma pneumoniae, or S. pneumoniae,
  • Pharyngitis/tonsillitis due to Streptococcus pyogenes,
  • Uncomplicated skin/skin structure infections due to methicillin-susceptible strains of Staphylococcus aureus or S. pyogenes.


Suppresses protein synthesis at the level of the 50S bacterial ribosome.

Therapeutic effects

Bacteriostatic action against susceptible bacteria.
Active against gram-positive aerobes including:
  • S. aureus (methicillin-susceptible),
  • S. pneumoniae and S. pyogenes.
Active against gram-negative aerobes, including: :
  • H. influenzae,
  • L. pneumophila,
  • M. catarrhalis.
Also active against M. pneumoniae.


Absorption: Dirithromycin is a pro-drug. It is converted to erythromycylamine, the active compound, during intestinal absorption, resulting in bioavailability of 10%.
Distribution: Erythromycylamine—rapidly and widely distributed, resulting in high tissue concentrations.
Metabolism and Excretion: Erythromycylamine—81–97% eliminated in bile (fecal/hepatic route); 2% eliminated in urine.
Half-life: Erythromycylamine—2–36 hr.

Time/action profile (blood levels†)

POunknown4hr24 hr
†Of erythromycylamine


Contraindicated in: Hypersensitivity to dirithromycin, erythromycin, or other macrolide anti-infectives; Known, suspected, or potential bacteremia (serum levels are inadequate).
Use Cautiously in: Moderate or severe hepatic impairment; Pregnancy, lactation, or children < 12 yr (safety not established).

Adverse Reactions/Side Effects

Central nervous system

  • dizziness/vertigo
  • headache
  • insomnia
  • weakness


  • dyspnea
  • increased cough


  • pseudomembranous colitis (life-threatening)
  • abdominal pain
  • diarrhea
  • dyspepsia
  • flatulence
  • nausea
  • vomiting


  • vaginitis


  • pruritus/urticaria
  • rash


Drug-Drug interaction

Absorption slightly ↑ when used with antacids or H2–receptor antagonists.May ↑ blood levels of triazolam,digoxin,warfarin,ergotamine,cyclosporine,carbamazepine,alfentanil,disopyramide,phenytoin,bromocriptine,valproic acid,lovastatin, and simvastatin.Food increases absorption.


Oral (Adults and Children > 12 yr) 500 mg/day as a single dose for 5–14 days (duration depends upon the indication).


Tablets: 250 mg

Nursing implications

Nursing assessment

  • Assess patient for infection (vital signs; appearance of wound, sputum, urine, and stool; WBC) at beginning of and throughout course of therapy.
  • Obtain specimens for culture and sensitivity prior to initiating therapy. First dose may be given before receiving results.
  • Lab Test Considerations: May cause increased platelet count, CPK, eosinophils, and serum potassium, and decreased serum bicarbonate concentrations.

Potential Nursing Diagnoses

Risk for infection (Indications,  Side Effects)
Deficient knowledge, related to medication regimen (Patient/Family Teaching)
Noncompliance (Patient/Family Teaching)


  • Oral: Administer with food or within 1 hr of having eaten. Tablets should be swallowed whole; do not crush, break, or chew.

Patient/Family Teaching

  • Instruct patients to take medication exactly as directed and to finish the drug completely, even if feeling better. Advise patients that sharing of this medication may be dangerous.
  • Advise patient to report the signs of superinfection (black, furry overgrowth on the tongue; vaginal itching or discharge; loose or foul-smelling stools).
  • Instruct patient to notify health care professional if fever and diarrhea develop, especially if stool contains blood, pus, or mucus. Advise patient not to treat diarrhea without consulting health care professional.
  • Advise patient to notify health care professional if pregnancy is planned or suspected.
  • Instruct the patient to notify health care professional if symptoms do not improve within a few days.

Evaluation/Desired Outcomes

  • Resolution of the signs and symptoms of infection. Length of time for complete resolution depends on the organism and site of infection.


Dirithromycin Infectious disease A broad-spectrum antibiotic used to manage exacerbation of chronic bronchitis by H influenzae and skin infection due to S pyogenes
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