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clarithromycin (kla-rith-roe-mye-sin)

Biaxin, Biaxin XL


Therapeutic: agents for atypical mycobacterium, anti-infectives, antiulcer agents

Pharmacologic: macrolides


Respiratory tract infections including streptococcal pharyngitis, sinusitis, bronchitis, and pneumonia. Treatment (with ethambutol) and prevention of disseminated Mycobacterium avium complex (MAC). Treatment of following pediatric infections: Otitis media, Sinusitis, Pharyngitis, Skin/skin structure infections. Part of a combination regimen for ulcer disease due to Helicobacter pylori. Endocarditis prophylaxis.


Inhibits protein synthesis at the level of the 50S bacterial ribosome. Therapeutic Effects: Bacteriostatic action. Spectrum: Active against these gram-positive aerobic bacteria: Staphylococcus aureus, Streptococcus pneumoniae, S.s pyogenes (group A strep). Active against these gram-negative aerobic bacteria: Haemophilus influenzae, Moraxella catarrhalis. Also active against Mycoplasma, Legionella, H. pylori, M. avium.

Adverse Reactions/Side Effects

CNS: headache. Derm: pruritus, rash, Stevens-Johnson syndrome. GI: PSEUDOMEMBRANOUS COLITIS, abdominal pain/discomfort, abnormal taste, diarrhea, dyspepsia, nausea.


Examination and Evaluation

  • Be alert for signs of pseudomembranous colitis, including diarrhea, abdominal pain, fever, pus or mucus in stools, and other severe or prolonged GI problems (nausea, vomiting, heartburn). Notify physician or nursing staff immediately of these signs.

  • Monitor rashes or other skin reactions (pruritus, hives, acne, abnormal sweating, exfoliation). Notify physician immediately because certain skin reactions may indicate serious hypersensitivity reactions (Stevens-Johnson syndrome).


  • Always wash hands thoroughly and disinfect equipment (whirlpools, electrotherapeutic devices, treatment tables, and so forth) to help prevent the spread of infection. Employ universal precautions or isolation procedures as indicated for specific patients.

Patient/Client-Related Instruction

  • Advise patient about the likelihood of GI reactions, including nausea, diarrhea, indigestion, abnormal taste, and abdominal pain. Instruct patient to report severe or prolonged GI problems.


Absorption: Rapidly absorbed (50%) after oral administration.

Distribution: Widely distributed; tissue levels may exceed those in serum.

Protein Binding: 65–70%.

Metabolism and Excretion: 10–15% converted by the liver to 14-hydroxyclarithromycin, which has anti-infective activity; 20–30% excreted unchanged in urine. Metabolized by and also inhibits the CYP3A enzyme system.

Half-life: Dose dependent and prolonged with renal dysfunction: 250-mg dose—3–4 hr; 500-mg dose—5–7 hr.

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TIME/ACTION PROFILE (serum levels)

PO unknown 2 hr 12 hr
PO-XL unknown 4 hr 24 hr


Contraindicated in: Hypersensitivity to clarithromycin, erythromycin, or other macrolide anti-infectives; Concurrent use of pimozide; OB: Avoid use during pregnancy unless no alternatives are available; Lactation: Not recommend for breast-feeding women.

Use Cautiously in: Severe liver or renal impairment (dose ...

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