Biaxin


clarithromycin

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

Biaxin

(trade name),

Biaxin XL

(trade name)

Classification

Therapeutic: agents atypical mycobacterium
Pharmacologic: macrolides
Pregnancy Category: C

Indications

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.

Action

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

Therapeutic effects

Bacteriostatic action.Active against these gram-positive aerobic bacteria:
  • Staphylococcus aureus,
  • S. pneumoniae,
  • 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.

Pharmacokinetics

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.

Time/action profile (serum levels)

ROUTEONSETPEAKDURATION
POunknown 2 hr12 hr
PO-XLunknown4 hr24 hr

Contraindications/Precautions

Contraindicated in: Hypersensitivity to clarithromycin, erythromycin, or other macrolide anti-infectives;History of cholestatic jaundice or hepatic dysfunction with clarithromycinConcurrent use of pimozide, ergotamine, dihydroergotamine, lovastatin, simvastatin, quinidine, procainamide, dofetilide, amiodarone, or sotalolConcurrent use of colchicine in patients with hepatic or renal impairment;QT interval prolongation, hypokalemia, hypomagnesemia, or bradycardia Obstetric: Avoid use during pregnancy unless no alternatives are available; Lactation: Not recommended for breast-feeding women.Use Cautiously in: Severe liver or renal impairment (dose adjustment required if CCr <30 mL/min);Myasthenia gravis; Geriatric: May have ↑ risk of QT interval prolongation

Adverse Reactions/Side Effects

Central nervous system

  • headache

Cardiovascular

  • torsades de pointes (life-threatening)
  • QT interval prolongation

Dermatologic

  • stevens-johnson syndrome (life-threatening)
  • pruritus
  • rash

Gastrointestinal

  • hepatotoxicity (life-threatening)
  • pseudomembranous colitis (life-threatening)
  • abdominal pain/discomfort
  • abnormal taste
  • diarrhea
  • dyspepsia
  • nausea

Interactions

Drug-Drug interaction

Clarithromycin is an inhibitor of the CYP3A enzyme system. Concurrent use with other agents metabolized by this system can ↑ levels and risk of toxicity.May prolong the QT interval and ↑ risk of arrhythmias withpimozide; concurrent use contraindicated.May ↑ levels of ergotamine and dihydroergotamine and risk for acute ergot toxicity; concurrent use contraindicated.Quinidine, procainamide, dofetilide, sotalol, and amiodarone may ↑ risk of QT interval prolongation; concurrent use should be avoided↑ risk of rhabdomyolysis with lovastatin and simvastatin ; concurrent use contraindicatedMay ↑ serum levels and the risk of toxicity from carbamazepine, some benzodiazepines (midazolam, triazolam, alprazolam), cyclosporine, disopyramide, quinidine, ergot alkaloids, felodipine, omeprazole, tacrolimus, digoxin, or theophylline.May ↑ levels and effects of omeprazole.Ritonavir ↑ blood levels (↓ clarithromycin dose in patients with CCr <60 mL/min).↑ levels and risk of myopathy from atorvastatin and pravastatin ; use lowest dose of these agents; do not exceed atorvastatin dose of 20 mg/day or pravastatin dose of 40 mg/day.May ↑ or ↓ effects of zidovudine.Blood levels are ↑ by delavirdine and fluconazole.Blood levels may be ↓ by rifampin, rifabutin, efavirenz, and nevirapine.May ↑ levels and risk of toxicity from colchicine ; ↓ colchicine dose in patients with normal renal and hepatic function; concurrent use is contraindicated in patients with renal or hepatic impairment.May ↑ verapamil levels and the risk for hypotension, bradycardia, and lactic acidosis.May ↑ warfarin levels and the risk for bleeding.May ↑ blood levels and effects of sildenafil, tadalafil, and vardenafil ; concurrent use not recommended.May ↑ levels of tolterodine.Concurrent use with atazanavir may ↑ clarithromycin and atazanavir levels; ↓ clarithromycin dose by 50%.Concurrent use with itraconazole may ↑ clarithromycin and itraconazole levels.Concurrent use with saquinavir may ↑ clarithromycin and saquinavir levels.

Route/Dosage

Oral (Adults) Pharyngitis/tonsillitis—250 mg q 12 hr for 10 days; Acute maxillary sinusitis—500 mg q 12 hr for 14 days or 1000 mg once daily for 14 days as XL tablets; Acute exacerbation of chronic bronchitis—250–500 mg q 12 hr for 7–14 days or 1000 mg once daily for 7 days as XL tablets; Community-Acquired pneumonia—250 mg q 12 hr for 7–14 days or 1000 mg once daily for 7 days as XL tablets; Skin/skin structure infections—250 mg q 12 hr for 7–14 days; H. pylori—500 mg 2–3 times daily with a proton pump inhibitor (lansoprazole or omeprazole) or ranitidine with or without amoxicillin for 10–14 days; Endocarditis prophylaxis—500 mg 1 hr before procedure; MAC prophylaxis/treatment—500 mg twice daily, for active infection another antimycobacterial is required.Oral (Children) Most infections—15 mg/kg/day divided q 12 hr for 7–14 days (up to 500 mg/dose for MAC). Endocarditis prophylaxis—15 mg/kg 1 hr before procedure.

Renal Impairment

Oral (Adults) CCr <30 mL/min—250 mg 1–2 times daily, a 500-mg initial dose may be used.Oral (Children) CCr <30 mL/min—decrease dose by 50% or double dosing interval.

Availability (generic available)

Tablets: 250 mg, 500 mg Extended-release tablets: 500 mg Oral suspensionfruit punch and vanilla flavors: 125 mg/5 mL, 250 mg/5 mL In combination with: amoxicillin and lansoprazole as part of a compliance package (Prevpac); See combination drugs.

Nursing implications

Nursing assessment

  • Assess patient for infection (vital signs; appearance of wound, sputum, urine, and stool; WBC) at beginning of and during therapy.
  • Obtain specimens for culture and sensitivity before initiating therapy. First dose may be given before receiving results.
  • Monitor bowel function. Diarrhea, abdominal cramping, fever, and bloody stools should be reported to health care professional promptly as a sign of pseudomembranous colitis. May begin up to several weeks following cessation of therapy.
  • Assess patient for skin rash frequently during therapy. Discontinue clarithromycin at first sign of rash; may be life-threatening. Stevens-Johnson syndrome may develop. Treat symptomatically; may recur once treatment is stopped.
  • Ulcers: Assess patient for epigastric or abdominal pain and frank or occult blood in the stool, emesis, or gastric aspirate.
  • Lab Test Considerations: May rarely cause ↑ serum AST, ALT, total bilirubin, and alkaline phosphatase concentrations.
    • May occasionally cause ↑ BUN.

Potential Nursing Diagnoses

Risk for infection (Indications, Side Effects)
Noncompliance (Patient/Family Teaching)

Implementation

  • Oral: Administer around the clock, without regard to meals; may be administered with milk. Food slows but does not decrease the extent of absorption.
    • Administer XL tablets with food or milk; do not crush, break, or chew.
    • Shake suspension well before administration. Store suspension at room temperature; do not refrigerate.
    • Do not administer within 4 hr of zidovudine.

Patient/Family Teaching

  • Instruct patient to take medication around the clock and to finish the drug completely as directed, even if feeling better. Take missed doses as soon as possible, unless almost time for next dose. Do not double doses. Advise patient 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 rash, or fever and diarrhea develop, especially if stool contains blood, pus, or mucus. Advise patient not to treat diarrhea without consulting health care professional.
  • Caution patients taking zidovudine that clarithromycin and zidovudine must be taken at least 4 hr apart.
  • Advise patient to notify health care professional immediately if pregnancy is planned or suspected or if breast feeding.
  • 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.
  • Treatment of ulcers.
  • Endocarditis prophylaxis.

Biaxin

(bī-ăk′sĭn) A trademark for the drug clarithromycin.

Biaxin®

Clarithromycin, see there.