Coadministration of gatifloxacin and multivitamin preparation containing minerals: potential treatment failure in an elderly patient.
OBJECTIVE
To report a case of probable treatment failure in a patient receiving gatifloxacin and a multivitamin preparation containing minerals.


METHODS
A 77-year-old white woman was prescribed gatifloxacin for hospital-acquired bacterial pneumonia. She was also receiving calcium carbonate 500 mg twice daily and a multivitamin preparation containing minerals once a day. Three days after gatifloxacin was started, the patient was still febrile, coughing, and not responding clinically. It was noted that nurses were administering the gatifloxacin tablet at the same time as the multivitamin tablet. The time of administration for gatifloxacin was changed to 6 hours after the patient received her multivitamin preparation. Two days later, she clinically improved.


CONCLUSIONS
Studies have shown that the bioavailability of gatifloxacin is decreased with concurrent administration of antacids containing aluminum or magnesium; dietary supplements containing zinc, magnesium, and iron; multivitamin preparations containing minerals; and sucralfate. An objective causality assessment revealed that the adverse drug effect was probable.


CONCLUSIONS
This case illustrates the need to recognize this potential interaction and to know how to avoid possible treatment failure.
Mallet
Louise
L
Faculty of Pharmacy, University of Montréal, Montréal, Québec, Canada. louise.mallet@umontreal.ca
Huang
Allen
A
D000368:Aged; D000900:Anti-Bacterial Agents / Q000008:administration & dosage* / Q000493:pharmacokinetics; D001682:Biological Availability; D004334:Drug Administration Schedule; D004347:Drug Interactions; D005260:Female; D024841:Fluoroquinolones / Q000008:administration & dosage* / Q000493:pharmacokinetics; D000077734:Gatifloxacin; D006801:Humans; D008670:Metals / Q000008:administration & dosage; D008903:Minerals / Q000008:administration & dosage*; D017211:Treatment Failure; D014815:Vitamins / Q000008:administration & dosage
D000900:Anti-Bacterial Agents; D024841:Fluoroquinolones; D008670:Metals; D008903:Minerals; D014815:Vitamins; D000077734:Gatifloxacin