Drug Interaction Report

ADJUST DOSING INTERVAL: Coadministration of oral probiotic preparations with oral antibiotics may reduce the efficacy of the probiotic. It has been theorized that concomitant antibiotics may kill the live organisms found in lactobacillus-, bacillus coagulans-, and bifidobacteria-containing oral probiotic preparations. However, the clinical significance of the interaction has not been established.

MANAGEMENT: Although data are limited, it may be prudent to advise patients to take oral probiotics at least 1 to 2 hours before or after an oral antibiotic.

ADJUST DOSING INTERVAL: Coadministration of oral probiotic preparations with oral antibiotics may reduce the efficacy of the probiotic. It has been theorized that concomitant antibiotics may kill the live organisms found in lactobacillus-, bacillus coagulans-, and bifidobacteria-containing oral probiotic preparations. However, the clinical significance of the interaction has not been established.

MANAGEMENT: Although data are limited, it may be prudent to advise patients to take oral probiotics at least 1 to 2 hours before or after an oral antibiotic.

Although some in vitro data indicate synergism between macrolide antibiotics and penicillins, other in vitro data indicate antagonism. When these drugs are given together, neither has predictable therapeutic efficacy. Data are available for erythromycin, although theoretically this interaction could occur with any macrolide. Except for monitoring of the effectiveness of antibiotic therapy, no special precautions appear to be necessary.

Clarithromycin may increase and prolong the omeprazole plasma concentration. The mechanism may be related to clarithromycin inhibition of hepatic cytochrome P450 enzymes responsible for omeprazole metabolism. Coadministration of omeprazole may result in an increase in clarithromycin and 14-(R)-hydroxyclarithromycin plasma concentrations. These increases may be due to the effect of omeprazole on gastric pH.

Grapefruit juice may delay the gastrointestinal absorption of clarithromycin but does not appear to affect the overall extent of absorption or inhibit the metabolism of clarithromycin. The mechanism of interaction is unknown but may be related to competition for intestinal CYP450 3A4 and/or absorptive sites. In an open-label, randomized, crossover study consisting of 12 healthy subjects, coadministration with grapefruit juice increased the time to reach peak plasma concentration (Tmax) of both clarithromycin and 14-hydroxyclarithromycin (the active metabolite) by 80% and 104%, respectively, compared to water. Other pharmacokinetic parameters were not significantly altered. This interaction is unlikely to be of clinical significance.