APX-ROXITHROMYCIN

What it is

APX-ROXITHROMYCIN is a semisynthetic macrolide antibiotic. It is available as 150 mg and 300 mg tablets. Roxithromycin is bacteriostatic at low concentrations and bactericidal at high concentrations, and binds to the 50S subunit of the 70S ribosome, thereby disrupting bacterial protein synthesis.

Approved indications

**Adults** — Acute pharyngitis, tonsillitis and sinusitis. — Acute bronchitis and acute exacerbations of chronic bronchitis; community acquired pneumonia. — Skin and skin structure infections. — Non-gonococcal urethritis. **Children** — Acute pharyngitis, acute tonsillitis, impetigo.

Dosing overview

The recommended dosage for adults is 300 mg per day, which may be taken as one 300 mg tablet daily, or one 150 mg tablet twice daily, or two 150 mg tablets once daily. For atypical pneumonia, the recommended dosage is 150 mg twice daily. In children, roxithromycin is administered twice daily at a dose of 5 to 8 mg/kg/day. APX-ROXITHROMYCIN should be taken at least 15 minutes before food or on an empty stomach (more than three hours after a meal). The usual duration of treatment is five to ten days depending on the indication and clinical response, although streptococcal throat infections require at least ten days of therapy.

Key safety warnings

Prolonged or repeated use of antibiotics including roxithromycin may result in superinfection by resistant organisms, and roxithromycin should be discontinued and appropriate therapy instituted in such cases. Antibiotic associated pseudomembranous colitis has been reported with many antibiotics, with a toxin produced by *Clostridium difficile* appearing to be the primary cause. The severity of the colitis may range from mild to life threatening, and it is important to consider this diagnosis in patients who develop diarrhoea or colitis in association with antibiotic use. Ventricular arrhythmias associated with prolonged QT interval, including ventricular tachycardia and torsades de pointes have been reported with macrolide antibiotics including roxithromycin. Prescribers should consider the risk of QT prolongation when weighing the risks and benefits for at-risk groups. Cases of severe bullous skin reactions such as Stevens Johnson Syndrome or Toxic Epidermal Necrosis have been reported with roxithromycin, and treatment should be discontinued if symptoms or signs of these conditions are present. Increased INR levels have been reported in patients when roxithromycin and coumarin anticoagulants are used concomitantly, and patients using both should be closely monitored.

Contraindications

Known hypersensitivity to macrolides, including erythromycin. Severely impaired hepatic function. Concomitant therapy with vasoconstrictive ergot alkaloids.

PBS listing

The document provided does not contain information about PBS listing status, restriction type, or ex-manufacturer price for APX-ROXITHROMYCIN.

Regulatory history

APX-ROXITHROMYCIN received initial approval on 2 December 2005. The 150 mg tablet and 300 mg tablet variants were first listed on the ARTG on 4 May 2020.