Clarithromycin
Clarithromycin (Biaxin)
Clarithromycin
(klah- rith-roh- MY-sin)
Pregnancy Category: C Biaxin (Rx)

Classification: Antibiotic, macrolide

See Also: See also Anti-Infectives .

Action/Kinetics: Macrolide antibiotic that acts by binding to the 50S ribosomal subunit of susceptible organisms, thus interfering with or inhibiting microbial protein synthesis. Rapidly absorbed from the GI tract although food slightly delays the onset of absorption and the formation of the active metabolite but does not affect the extent of the bioavailability. Peak serum levels: When fasting, 2 hr for the tablet and 3 hr for the suspension. Steady-state peak serum levels: 1 mcg/mL within 2-3 days after 250 mg q 12 hr and 2-3 mcg/mL after 500 mg q 12 hr. Clarithromycin and 14-OH clarithromycin (active metabolite) are readily distributed to body tissues and fluids. t 1/2, elimination: 3-7 hr (depending on the dose) for clarithromycin and 5-6 hr for 14-OH clarithromycin. Up to 30% of a dose is excreted unchanged in the urine.

Uses: Mild to moderate infections caused by susceptible strains of the following. Adults. (1) Pharyngitis/tonsillitis due to Streptococcus pyogenes. (2) Acute maxillary sinusitis or acute bacterial exacerbaton of chronic bronchitis due to Sreptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. The active metabolite, 14-OH clarithromycin, has significant activity (twice the parent compound) against H. influenzae. (3) Pneumonia due to Mycoplasma pneumoniae S. pneumoniae, or Chlamydia pneumoniae. (4) Uncomplicated skin and skin structure infections due to Staphylococcus aureus or S. pyogenes. (5) Treatment of disseminated mycobacterial infections due to Mycobacterium avium (commonly seen in AIDS clients) and M. intracellulare. Prevention of disseminated M. avium complex in individuals with advanced HIV. (6) Used with omeprazole and ranitidine bismuth citrate (Tritec) or with amoxicillin and lansoprazole (Prevpac) for the eradication of Helicobacter pylori infection in clients with active duodenal ulcers associated with H. pylori infection.
Children. (1) Pharyngitis or tonsillitis due to S. pyogenes. (2) Acute maxillary sinusitis or acute otitis media due to S. pneumoniae, H. influenzae and M. catarrhalis. (3) Uncomplicated skin and skin structure infections due to S. aureus or S. pyogenes. (4) Disseminated mycobacterial infections due to M. avium or M. intracellulare. Prevention of disseminated M. avium complex disease in clients with advanced HIV infection. (5) Community-acquired pneumonia caused by M. pneumoniae, Chlamydia pneumoniae and S. pneumoniae.

Contraindications: Hypersensitivity to clarithromycin, other macrolide antibiotics, or erythromycin. Clients taking astemizole, terfenadine, cisapride, or pimozide. Use with ranitidine bismuth citrate in those with a history of acute porphyria.

Special Concerns: Use with caution in severe renal impairment with or without concomitant hepatic impairment and during lactation. Safety and effectiveness in children less than 6 months of age have not been determined. Safety has not been determined in MAC clients less than 20 months of age.

Side Effects: GI: Diarrhea, nausea, abnormal taste, dyspepsia, abdominal discomfort or pain, pseudomembranous colitis, glossitis, stomatitis, oral moniliasis, vomiting. CNS: Headache, dizziness, behavioral changes, confusion, depersonalization, disorientation, hallucinations, insomnia, nightmares, vertigo. Allergic: Urticaria, mild skin eruptions and, rarely, anaphylaxis and Stevens-Johnson syndrome. Hepatic: Hepatocellular cholestatic hepatitis with or without jaundice, increased liver enzymes, hepatic failure. Miscellaneous: Hearing loss (usually reversible), alteration of sense of smell (usually with taste perversion).
In children, the most common side effects are diarrhea, vomiting, abdominal pain, rash, and headache.

Laboratory Test Alterations: ALT, AST, GGT, alkaline phosphatase, LDH, total bilirubin, BUN, serum creatinine, PT. WBC count.

Drug Interactions: See also Drug Interactions for Erythromycins . Anticoagulants / Anticoagulant effects Astemizole / Astemizole levels; side effects, including ventricular arrhythmias, torsades de pointes, cardiac arrest, and death Benzodiazepines / Plasma levels of certain benzodizepines and prolonged CNS effects Buspirone / Buspirone plasma levels risk of side effects Carbamazepine / Carbamazepine blood levels Cisapride / Possibility of serious cardiac arrhythmias, including VT, VF, torsade de pointes, and QT prolongation Cyclosporine Cyclosporine levels risk of nephrotoxicity and neurotoxicity Digoxin / Digoxin plasma levels R/T digoxin metabolism by the gut flora Disopyramide / Plasma levels arrhythmias and QT intervals Ergot alkaloids / Acute drug toxicity, including severe peripheral vasospasm and dysesthesia Fluconazole / Clarithromycin blood levels HMG-CoA Reductase Inhibitors / Risk of severe myopathy or rhabdomyolysis Omeprazole / Plasma levels of omeprazole, clarithromycin, and 14-OH-clarithromycin Pimozide / Risk of sudden death due to cardiac effects; do not use together Ranitidine bismuth citrate / Levels of ranitidine, bismuth citrate, and 14-OH clarithromycin Rifabutin, Rifampin / Effect of clarithromycin and GI side effects Tacrolimus / Tacrolimus plasma levels risk of toxicity (e.g., nephrotoxicity) Terfenadine / Plasma levels of the active acid metabolite of terfenadine; risk of cardiac arrhythmias, including QT interval prolongation Theophylline / Theophylline serum levels Triazolam / Risk of somnolence and confusion Verapamil / Possible severe hypotension and bradycardia AZT / Steady-state AZT levels in HIV-infected clients; however, peak serum AZT levels may be or

How Supplied: Granules for Oral Suspension after Reconstitution: 125 mg/5 mL, 250 mg/5 mL; Tablet: 250 mg, 500 mg

Dosage
?Tablets, Oral Suspension Pharyngitis, tonsillitis.
Adults: 250 mg q 12 hr for 10 days.
Acute exacerbation of chronic bronchitis due to S. pneumoniae or M. catarrhalis; pneumonia due to S. pneumoniae or M. pneumoniae; uncomplicated skin and skin structure infections.
Adults: 250 mg q 12 hr for 7-14 days.
Acute maxillary sinusitis, acute exacerbation of chronic bronchitis due to H. influenzae.
Adults: 500 mg q 12 hr for 7-14 days.
Disseminated M. avium complex or prophylaxis of M. avium complex.
Adults: 500 mg b.i.d.; children: 7.5 mg/kg b.i.d. up to 500 mg b.i.d.

NOTE: The usual daily dose for children is 15 mg/kg q 12 hr for 10 days. Community-acquired pneumonia in children.
15 mg/kg/day of the suspension, divided and given q 12 hr for 10 days.
Active duodenal ulcers associated with H. pylori infection.
The following drug regimens are used: (a) Clarithromycin, 500 mg b.i.d., amoxcillin, 1,000 mg b.i.d., with either lansoprazole, 30 mg b.i.d. or omeprazole, 20 mg b.i.d., all for ten days. (b) Clarithromycin, 500 mg b.i.d. and metronidazole, 500 mg b.i.d., each for two weeks, with either lansoprazole, 30 mg b.i.d., or omeprazole, 20 mg b.i.d., for 4 weeks. (c) Clarithromycin, 500 mg b.i.d. for 2 weeks with either amoxicillin, 1,000 mg b.i.d., metronidazole, 500 mg b.i.d., or tetracycline, 500 mg b.i.d. for 2 weeks. Also, ranitidine bismuth citrate, 400 mg b.i.d., for 4 weeks.