What counseling should be given regarding tetracycline use and dairy products?

• A. It can be taken with milk without issue
• B. Do not take with milk, calcium, or iron supplements within a couple hours; can reduce absorption
• C. Tetracycline should be taken with orange juice to enhance absorption
• D. Dairy products increase tetracycline absorption

Answer: (B)

Tetracyclines bind strongly to divalent cations such as calcium found in milk and calcium-containing supplements, forming insoluble chelates that the body cannot absorb. Because of this, taking tetracycline with dairy products or within a couple of hours of calcium or iron supplements markedly lowers the drug’s absorption, leading to lower blood levels and potentially ineffective treatment. The best counseling is to separate dosing from these substances by about 2 hours—neither with milk nor with calcium or iron supplements—so the antibiotic can be absorbed properly. In practice, take tetracycline with a full glass of water, and plan doses so dairy or calcium/iron products aren’t consumed close to the time of dosing.