ROXAR

What it is

ROXAR is available as 150 mg and 300 mg film-coated tablets containing roxithromycin. Roxithromycin is a semisynthetic macrolide antibiotic. It is bacteriostatic at low concentrations and bactericidal at high concentrations, binding to the 50S subunit of the 70S ribosome to disrupt bacterial protein synthesis.

Approved indications

**Adults** — Upper respiratory tract infection: acute pharyngitis, tonsillitis and sinusitis. — Lower respiratory tract infection: 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

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. Streptococcal throat infections require at least ten days of therapy.

Key safety warnings

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 may range from mild to life threatening. It is important to consider this diagnosis in patients who develop diarrhoea or colitis in association with antibiotic use, as this may occur up to several weeks after cessation of antibiotic therapy. Cases of severe bullous skin reactions such as Stevens Johnson Syndrome or Toxic Epidermal Necrosis have been reported with roxithromycin; if symptoms or signs such as progressive skin rash often with blisters or mucosal lesions are present, treatment should be discontinued. 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 risks and benefits for at-risk groups, including those predisposed to QT interval prolongation, those taking other QT-prolonging medication, those with electrolyte disturbance (particularly hypokalaemia and hypomagnesaemia), and those with clinically relevant bradycardia, cardiac arrhythmia or cardiac insufficiency. Severe vasoconstriction ("ergotism") with possibly necrosis of the extremities has been reported when macrolide antibiotics have been associated with vasoconstrictive ergot alkaloids; absence of treatment by these alkaloids must always be checked before prescribing roxithromycin. Roxithromycin may have the potential to aggravate myasthenia gravis.

Contraindications

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

PBS listing

ROXAR 300 mg and 150 mg tablets are listed on the PBS with three items each, unrestricted streamlined dispensing, at an ex-manufacturer price of A$2.81 per unit.

Regulatory history

ROXAR was first approved on 2 December 2005. Both the 300 mg and 150 mg tablet formulations were first listed on the ARTG on 16 December 2005.