Roxithromycin Omeprazole

Quadruple therapy (omeprazole, amoxicUhn, roxithromycin, and metronidazole for 1 week) has been studied in an open trial in 169 patients with H. pylori (8). This regimen achieved an eradication rate of 92%. It was also beneficial in patients infected with pretreatment resistant strains to the antibiotics, in which cases the eradication rates achieved (over 90%) were similar to eradication rates in patients infected with sensitive strains. Compliance was good and there was only one serious adverse effect, anaphylaxis, probably due to amoxicillin. Frequent adverse effects were abdominal distension (10%), glossitis (9%), and diarrhea (8%). 

The effect of omeprazole on roxithromycin concentrations in plasma and gastric tissue has been investigated in 12 healthy volunteers who took omeprazole 20 mg bd with or without roxithromycin 300 mg bd over 6 days (38). The medications were well tolerated, with only mild adverse events. The more frequent adverse events were nausea, bloating, and diarrhea. Omeprazole and roxithromycin did not alter the systemic availability of each other. However, omeprazole increased the local concentration of the antibiotic in the stomach. 

Cellini, L., Marzio, L., Di Girolamo, A., Allocati, N., Grossi, L., and Dainelli, B. (1991). Enhanced clearing of Helicobacter pylori after omeprazole plus roxithromycin treatment. FEMS Microbiol. Lett. 68, 255-257. 

A study of roxithromycin 300 mg twice daily with omeprazole 20 mg twice daily or with lansoprazole 30 mg twice daily, for 6 days found that neither PPI significantly affected the pharmacokinetics of roxithromycin. ... 

The pharmacokinetic interactions between clarithromycin and omeprazole, esomeprazole and lansoprazole are established. However, none of the changes reported represents an adverse interaction, but they may help to explain why concurrent use is valuable in the eradication of Helicobacter pylori. Erythromycin is likely to interact similarly, whereas roxithromycin does not. Pantoprazole is not affected by macrolides. 

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