CLARITHRO

What it is

CLARITHRO is a film-coated tablet containing clarithromycin, available in strengths of 250 mg and 500 mg. Clarithromycin is a semi-synthetic macrolide antibiotic. It exerts its antibacterial action by binding to the 50S ribosomal subunits of susceptible organisms and inhibiting protein synthesis.

Approved indications

**For adults and children 12 years and older:** — Acute streptococcal pharyngitis. — Community acquired pneumonia due to Chlamydia pneumoniae, Mycoplasma pneumoniae, Legionella pneumophila and Streptococcus pneumoniae. — Uncomplicated skin and skin structure infections due to Staphylococcus aureus or Streptococcus pyogenes. — Disseminated or localised mycobacterial infections due to Mycobacterium avium or Mycobacterium intracellulare and skin and skin structure infections due to Mycobacterium chelonae. — Prevention of disseminated Mycobacterium avium complex infection in HIV-infected adults with CD4 lymphocyte counts less than 75 cells/mm³. — Acute bacterial exacerbation of chronic bronchitis due to Haemophilus influenzae, Moraxella catarrhalis or Streptococcus pneumoniae. — Combination therapy for the treatment of peptic ulcer disease associated with Helicobacter pylori infection. **For children:** — Acute streptococcal pharyngitis and tonsillitis caused by Streptococcus pyogenes. — Community acquired pneumonia including infections due to Chlamydia pneumoniae, Mycoplasma pneumoniae and Legionella pneumophila. — Skin and skin structure infections (e.g. impetigo). — Disseminated or localised infections due to Mycobacterium avium or Mycobacterium intracellulare in immunocompromised children, including those with HIV infection or AIDS. — Acute otitis media.

Dosing overview

For non-mycobacterial infections in adults and children 12 years and older, the usual recommended dosage of clarithromycin is 250 mg twice daily. In more severe infections, the dosage can be increased to 500 mg twice daily. The usual duration of therapy is 7 to 14 days. For the treatment of Legionella pneumophila infection, a dose of 500 mg twice daily for 4 weeks is appropriate. In patients with peptic ulcer due to H. pylori infection, clarithromycin can be administered in a dose of 500 mg twice daily in combination with other appropriate antimicrobial treatments and a proton pump inhibitor for 7–14 days. For mycobacterial infections in adults and children 12 years and older, the recommended dosage is 500 mg twice daily. For prophylaxis of disseminated Mycobacterium avium complex infections in HIV-infected adults with CD4 lymphocyte counts less than 75 cells/mm³, the recommended dosage is 500 mg twice daily. In patients with renal impairment with creatinine clearance less than 30 mL/min, the dosage of clarithromycin should be reduced by one-half to 250 mg once daily, or 250 mg twice daily in more severe infections.

Key safety warnings

Prolonged cardiac repolarization and QT interval, imparting a risk of developing cardiac arrhythmia and torsades de pointes, have been seen in treatment with macrolides including clarithromycin. Some observational studies have identified a rare short-term risk of arrhythmia, myocardial infarction and cardiovascular mortality associated with macrolides including clarithromycin. Consideration of these findings should be balanced with treatment benefits when prescribing clarithromycin. Exacerbation of symptoms of myasthenia gravis has been reported in patients receiving clarithromycin therapy. Clostridium difficile-associated diarrhoea (CDAD) has been reported with use of clarithromycin, and may range in severity from mild diarrhoea to fatal colitis. It is important to consider this diagnosis in patients who develop diarrhoea or colitis in association with antibiotic use (this may occur up to several weeks after cessation of antibiotic therapy). Hepatic dysfunction, including increased liver enzymes, and hepatocellular and/or cholestatic hepatitis, with or without jaundice, has been reported with clarithromycin. This hepatic dysfunction may be severe and is usually reversible. In some instances, hepatic failure with fatal outcome has been reported and generally has been associated with serious underlying diseases and/or concomitant medications.

Contraindications

CLARITHRO is contraindicated in patients with known hypersensitivity to macrolide antibiotic drugs or any of its excipients. Concurrent administration of clarithromycin and astemizole, terfenadine, cisapride, domperidone or pimozide is contraindicated, as this may result in QT prolongation and cardiac arrhythmias, including ventricular tachycardia, ventricular fibrillation, and torsades de pointes. Clarithromycin should not be given to patients with history of QT prolongation (congenital or documented acquired QT prolongation) or ventricular cardiac arrhythmia, including torsades de pointes. Clarithromycin should not be given to patients with electrolyte disturbances (hypokalaemia or hypomagnesaemia, due to the risk of prolongation of QT interval). Concomitant administration of clarithromycin and ergot alkaloids (e.g. ergotamine or dihydroergotamine) is contraindicated, as this may result in ergot toxicity. Concomitant administration of clarithromycin and ivabradine is contraindicated, as this may result in increased plasma exposure of ivabradine. Concomitant administration of clarithromycin and oral midazolam is contraindicated. Concomitant administration of clarithromycin and lomitapide is contraindicated. Clarithromycin should not be used concomitantly with HMG-CoA reductase inhibitors (statins) that are extensively metabolised by CYP3A4 (lovastatin or simvastatin) due to the increased risk of myopathy, including rhabdomyolysis. Clarithromycin should not be used concomitantly with colchicine. Concomitant administration with ticagrelor or ranolazine is contraindicated.

PBS listing

Information regarding PBS listing, including strength, item count, restriction type, and ex-manufacturer price, is not available in the provided source documents.

Regulatory history

CLARITHRO 250 mg clarithromycin tablets (blister pack and bottle) and CLARITHRO 500 mg clarithromycin tablets (blister pack and bottle) were first listed on the ARTG on 30 June 2006.