A 24-year-old woman starting doxycycline for acne should be counseled about which administration requirement to ensure adequate absorption?
- A Take it with milk to prevent gastric irritation
- B Crush the tablet and mix it with food
- C Avoid concurrent iron supplements and take it with a full glass of water while upright ✓
- D Take it immediately before lying down at night
Correct answer: C. Avoid concurrent iron supplements and take it with a full glass of water while upright
Explanation
Divalent and trivalent cations including calcium, iron, magnesium and aluminium chelate tetracyclines in the gut lumen and sharply reduce their absorption, so iron supplements and dairy must be separated from the dose. Swallowing with water in the upright position prevents pill-induced esophageal ulceration, a recognized doxycycline adverse effect.
Reference: Katzung's Basic and Clinical Pharmacology, 16th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.