Do not take indigestion remedies, or medicines containing iron or zinc, 2 hours before or after you take this medicine. Which medicine is described?

Do not take indigestion remedies, or medicines containing iron or zinc, 2 hours before or after you take this medicine. Which medicine is described?

• A. Doxycycline
• B. Amoxicillin
• C. Ciprofloxacin
• D. Azithromycin

Answer: (A)

Doxycycline is a tetracycline that forms chelate complexes with divalent and trivalent metal ions, such as iron or zinc, in the gut. When these minerals are present, they bind the antibiotic and prevent its absorption, lowering its effectiveness. That’s why you’re advised not to take indigestion remedies or products containing iron or zinc within about 2 hours of taking doxycycline. Amoxicillin and azithromycin aren’t notably affected by these metal chelation interactions, so they don’t require the same timing restriction. Ciprofloxacin does have some interactions with metals, but the classic counseling point described here specifically targets doxycycline and the iron/zinc-containing products.

Doxycycline is a tetracycline that forms chelate complexes with divalent and trivalent metal ions, such as iron or zinc, in the gut. When these minerals are present, they bind the antibiotic and prevent its absorption, lowering its effectiveness. That’s why you’re advised not to take indigestion remedies or products containing iron or zinc within about 2 hours of taking doxycycline. Amoxicillin and azithromycin aren’t notably affected by these metal chelation interactions, so they don’t require the same timing restriction. Ciprofloxacin does have some interactions with metals, but the classic counseling point described here specifically targets doxycycline and the iron/zinc-containing products.