Roxithromycin
Roxithromycin is a semi-synthetic macrolide antibiotic used to treat respiratory tract, urinary and soft tissue infections. It is a derivative of erythromycin - comprising the same 14-membered lactone ring - with an oxime-based side chain attached to the macrolide ring.
Roxithromycin was patented in 1980 and approved for medical use in 1987. It is available under several brand names in Australia, France, Germany, Israel, South Korea and New Zealand, but not in the United States. Roxithromycin has also been shown to possess antimalarial activity.
Side effects
The most common side effects are gastrointestinal: diarrhoea, nausea, abdominal pain and vomiting. Less common side effects include central or peripheral nervous system events such as headaches, dizziness, vertigo.Rarely seen side effects are rashes, abnormal liver function values and alteration in the senses of smell and taste.Drug interactions
Roxithromycin has fewer interactions than erythromycin as it has a lower affinity for cytochrome P450.Roxithromycin is not known to interact with hormonal contraceptives, prednisolone, carbamazepine, ranitidine or antacids.
When roxithromycin is administered with theophylline, some studies have shown an increase in the plasma concentration of theophylline. A change in dosage is usually not required but patients with high levels of theophylline at the start of the treatment should have their plasma levels monitored.
Roxithromycin appears to interact with warfarin. This is shown by an increase in prothrombin time and/or international normalised ratio in patients taking roxithromycin and warfarin concurrently. As a consequence, severe bleeding episodes have occurred.