General

Pronunciation
kla-RITH-roe-mye-sin

Trade Name(s)

• Biaxin

• Biaxin XL

Pregnancy Category
Category C

Ther. class.
agents atypical mycobacterium
anti-infectives
antiulcer agents

Pharm. class.
macrolides

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 Effect(s):
Bacteriostatic action

Spectrum:

• Active against these gram-positive aerobic bacteria:

» Staphylococcus aureus

» Streptococcus pneumoniae

» Streptococcus 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 dysfunction250-mg dose—3–4 hr; 500-mg dose—5–7 hr

TIME/ACTION PROFILE (serum levels)

ROUTE	ONSET	PEAK	DURATION
PO	unknown	2 hr	12 hr
PO-XL	unknown	4 hr	24 hr

Contraindication/Precautions

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 breastfeeding women

Use Cautiously in:

• Severe liver or renal impairment (dose adjustment required if CCr <30 ml/min)

• Myasthenia gravis

Adverse Reactions/Side Effects

CNS: headache.

Derm: pruritus, rash, Stevens-Johnson syndrome.

GI: PSEUDOMEMBRANOUS COLITIS, abdominal pain/discomfort, abnormal taste, diarrhea, dyspepsia, nausea.

*CAPITALS indicates life-threatening.
*italic indicates most frequent.

Interactions

Drug-Drug

• 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 with pimozide ; concurrent use is contraindicated

• Similar effects may occur with antiarrhythmics; ECG should be monitored for QTc prolongation and serum levels monitored

• May serum levels and the risk of toxicity from carbamazepine, some benzodiazepines (midazolam, triazolam, alprazolam), cyclosporine, buspirone, disopyramide, ergot alkaloids, felodipine, omeprazole, tacrolimus, digoxin, or theophylline

• Ritonavir increases blood levels ( clarithromycin dose in patients with CC <60 ml/min)

• levels of HMG-CoA reductase inhibitors and may risk of rhabdomyolysis

• May effect of warfarin and sildenafil (dose reduction may be warranted)

• May or effects of zidovudine

• Blood levels are by delavirdine and fluconazole

• Blood levels may be by rifampin and rifabutin. risk of colchicine toxicty when administered with colchicine, especially in the elderly

Route/Dosage

• PO (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.

• PO (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

• PO (Adults):
CCr <30 ml/min—250 mg 1-2 times daily, a 500-mg initial dose may be used.

• PO (Children):
CCr <30 ml/min—decrease dose by 50% or double dosing interval.

Availability

• Tablets: 250 mg, 500 mg

» Cost:
Generic: 250 mg $73.32/20, 500 mg $73.32/20.

• Extended-release tablets: 500 mg

» Cost: $109.99/20.

• Oral suspension (fruit punch and vanilla flavors): 125 mg/5 ml, 250 mg/5 ml

» Cost:
Generic: 125 mg/5 ml $39.98/100 ml, 250 mg/5 ml $71.38/100 ml.

• In combination with: amoxicillin and lansoprazole as part of a compliance package (Prevpac); See combination drugs

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

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, and alkaline phosphatase concentrations

» May occasionally cause BUN

Potential Nursing Diagnoses

• Risk for infection (Indications)(Side Effects)

• Noncompliance (Patient/Family Teaching)

Implementation

PO: Administer around the clock, without regard to meals. 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 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 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

• Treatment of ulcers

• Endocarditis prophylaxis

clarithromycin is a sample topic found in Davis's Drug Guide. All other sections of this record are viewable by clicking on the index in the left column, or by clicking on "Display all Sections" in the "Content Manager".

To find other Davis's Drug Guide topics, please login or purchase a subscription.