Roxithromycin

Roxithromycin is indicated in the treatment of infections caused by susceptible microorganisms-

• Respiratory infections like pneumonia, acute and chronic bronchitis, and bronchopneumonia
• ENT infections like tonsillitis, pharyngitis, sinusitis and otitis media.
• Skin infections like folliculitis, furuncles, cellulitis, carbuncles, pyoderma, impetigo and infected dermatitis.
• Genital infections like urethritis, prostatitis, cervicitis and salpingitis especially if produced by Chlamydia trachomatis.

Roxithromycin inhibits protein synthesis by irreversibly binding to the 50s ribosomal subunits thus blocking the transpeptidation or translocation reactions of susceptible organisms resulting in stunted cell growth.

Adult dose: The usual dose for adults is one 300 mg tablet once daily or one 150 mg tablet twice a day for at least two days after resolution of symptoms, a normal course of therapy is between 5 and 10 days. Roxithromycin is best administered on empty stomach. In severe hepatic impairment the dose is 150 mg once daily.

Pediatric dose: The dose for children is 2.5 to 5 mg/kg body weight twice a day. The following general guidelines can be followed

• 6 to 11 Kg: 25 mg Roxithromycin 12 hourly.
• 12 to 23 Kg: 50 mg Roxithromycin 12 hourly.
• 24 to 40 Kg: 100 mg Roxithromycin 12 hourly.

A normal course of therapy is between 5 and 10 days.

Roxithromycin does not have any affinity for cytochrome P-450 binding sites and thus is unlikely to produce drug interaction mediated by this enzymatic system. Roxithromycin shows mild interaction with theophylline though this has not been found to produce clinically relevant effects. Alteration in the pharmacokinetics of carbamazepine or warfarin has not been found. Antacids, H2- receptor antagonists and food has no effect on the absorption of Roxithromycin.

Roxithromycin should not be administered simultaneously with ergotamine or its derivatives as it may provoke arterial spasm and severe ischaemia.

Roxithromycin is well tolerated by patients of all age groups. Less than 4% of treated patients complain of side effects mainly nausea, abdominal pain, diarrhoea and hypersensitivity rash. Other side effects reported include vomiting, dizziness, headache, pruritus, dyspepsia, flatulence, tinnitus, vertigo and constipation. These are in general minor and do not necessitate withdrawal of therapy.

The safety of Roxithromycin in pregnancy has not been established. It appears in breast milk in small amounts and dose not produce adverse effects in the breast fed infant.

Roxithromycin should not be used in patients with a history of hypersensitivity to the drug. In patients with hepatic diseases the dose of Roxithromycin should not exceed 150 mg twice a day.

Macrolides.