DIRITHROMYCIN
| DIRITHROMYCIN (dir-ith-roe-my'sin) Dynabac Classifications: macrolide antibiotic; Therapeutic: antibiotic Prototype: Erythromycin Pregnancy Category: C |
Availability
250 mg enteric tablets
Action
Dirithromycin is an analog of erythromycin. It binds reversibly to the 50-S ribosomal subunit of the bacteria, thus inhibiting RNA-dependent protein synthesis in bacterial cells. It has no apparent effect on the cytochrome P-450 hepatic enzyme system as erythromycin does.
Therapeutic Effect
It is more active against gram-positive organisms than gram-negative organisms.
Uses
Acute bacterial exacerbations of chronic bronchitis, community-acquired pneumonia, pharyngitis/tonsillitis, uncomplicated skin/skin structure infections due to susceptible bacteria.
Contraindications
Known hypersensitivity to dirithromycin, erythromycin, or any other macrolide antibiotic; known or suspected bacteremias; viral infections; pregnancy (category C).
Cautious Use
Severe hepatic impairment, GI disease; lactation. Safety and effectiveness in children <12 y are not established.
Route & Dosage
| Bacterial Infections Adult/Child: PO 500 mg once/d |
Administration
Oral- Give with food or within 1 h of eating.
- Do not cut, crush, or chew tablets.
- Store at 15°–30° C (59°–86° F).
Adverse Effects (≥1%)
CNS: Headache, dizziness, asthenia. CV: Chest pain. GI: Abdominal pain, nausea, diarrhea, vomiting, dyspepsia, flatulence; elevated liver function tests (ALT, AST, GGT). Skin: Rash, urticaria. Respiratory: Dyspnea, asthma-like symptoms, rhinitis, pharyngitis, increased coughing.Interactions
Drug: May increase theophylline levels.Pharmacokinetics
Absorption: Readily absorbed from GI tract; 60–90% hydrolyzed to active metabolite, erythromycylamine, within 35 min. Peak: 1.5 h. Distribution: High tissue concentrations of active metabolite; slowly released back into the circulation. Metabolism: Rapidly converted to active metabolite, erythromycylamine, in absorption and distribution phases. Elimination: 81–97% in bile and feces. Half-Life: 20–50 h.Nursing Implications
Assessment & Drug Effects
- Take history of previous hypersensitivity to other macrolides (e.g., erythromycin) prior to initiation of therapy.
- Withhold drug and notify physician if signs and symptoms of hypersensitivity occur (see Appendix F).
- Monitor liver and renal function in patients with mild liver or renal impairment.
- Monitor for S&S of superinfection (see Appendix F).
- Monitor theophylline levels if given concurrently with dirithromycin.
- Note: Dirithromycin may increase the blood level of theophylline, necessitating theophylline dosage adjustment.
Patient & Family Education
- Take tablets whole and within 1 h of meals.
- Monitor for and report S&S of superinfection or pseudomembranous enterocolitis (see Appendix F).
- Report any worsening of signs and symptoms of infection.
Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; 
Canadian drug name; 
Prototype drug