Drug Interactions between delafloxacin and didanosine

ADJUST DOSING INTERVAL: Coadministration with didanosine buffered tablets or pediatric oral solution may significantly reduce the oral bioavailability of ciprofloxacin and other quinolone antibiotics. The mechanism is reduced quinolone absorption due to chelation with metallic cations from buffering agents and antacids used in certain formulations of didanosine. In a randomized, crossover study consisting of 12 healthy volunteers, simultaneous administration of didanosine placebo tablets (buffering agents without didanosine) reduced the mean peak plasma concentration (Cmax) and area under the concentration-time curve (AUC) of ciprofloxacin by 93% and 98%, respectively. In eight HIV-infected patients, the steady-state AUC of ciprofloxacin decreased an average of 26% when it was administered 2 hours prior to didanosine tablets. In a single subject given one dose of ciprofloxacin 2 hours after didanosine placebo tablets, ciprofloxacin AUC was reduced by more than 50%.

MANAGEMENT: Quinolones such as ciprofloxacin should be administered at least 2 hours before or 6 hours after didanosine buffered tablets or pediatric oral solution, and patients should be monitored for potentially decreased antimicrobial efficacy during concomitant therapy. Didanosine buffered powder for oral solution, which uses a citrate-phosphate buffer, and the delayed-release capsules, which are not buffered, are not expected to cause this interaction.