Which of the following would reduce the absorption of ciprofloxacin?
A.
Alcohol
B.
Intense physical exertion
C.
Fruit juices, in particular grapefruit juice
D.
Antacids or mineral supplements
The Correct Answer and Explanation is:
The correct answer is D. Antacids or mineral supplements.
Explanation:
Ciprofloxacin is a fluoroquinolone antibiotic used to treat a variety of bacterial infections. Its effectiveness depends on proper absorption into the bloodstream when taken orally. Certain substances can interfere with this absorption, rendering the medication less effective.
Interaction with Antacids or Mineral Supplements (D)
Ciprofloxacin binds to divalent and trivalent cations, such as magnesium (Mg²⁺), calcium (Ca²⁺), aluminum (Al³⁺), iron (Fe²⁺/Fe³⁺), and zinc (Zn²⁺), which are often found in antacids and mineral supplements. When these cations are present in the stomach, they form chelates (complexes) with ciprofloxacin, preventing its absorption in the gastrointestinal tract. This can significantly reduce the bioavailability of ciprofloxacin, making the antibiotic less effective in treating infections.
For this reason, patients are advised to avoid taking antacids, calcium supplements, iron supplements, or multivitamins within 2-6 hours of ciprofloxacin administration. By spacing out these medications, the risk of interaction is minimized, allowing ciprofloxacin to be absorbed properly.
Why the Other Options Are Incorrect
- A. Alcohol: While alcohol consumption is generally discouraged during antibiotic therapy due to potential liver strain and the risk of side effects, it does not directly reduce the absorption of ciprofloxacin. However, alcohol might exacerbate some side effects like dizziness or nausea but doesn’t interfere with the antibiotic’s absorption.
- B. Intense physical exertion: Exercise does not affect the absorption of ciprofloxacin. However, fluoroquinolones, including ciprofloxacin, are associated with an increased risk of tendonitis and tendon rupture, particularly in people engaging in strenuous activities. While exertion may exacerbate side effects, it does not directly reduce the drug’s absorption.
- C. Fruit juices, in particular grapefruit juice: Grapefruit juice is known to interfere with the metabolism of many drugs by inhibiting the enzyme CYP3A4 in the liver, but ciprofloxacin is primarily metabolized through a different pathway. While it is wise to avoid grapefruit juice with certain medications, it does not significantly impact the absorption of ciprofloxacin.
Conclusion:
The most critical interaction that reduces the absorption of ciprofloxacin involves antacids or mineral supplements containing divalent or trivalent cations, as they prevent proper absorption of the drug by forming non-absorbable complexes. This interaction can significantly reduce ciprofloxacin’s effectiveness, making option D the correct choice.