PTCB Certified Pharmacy Technician (PTCE)MedicationsHard
A patient approaches the pharmacy counter requesting an over-the-counter medication for heartburn. They mention taking 'warfarin' daily. Which of the following antacids would be the SAFEST recommendation, considering the patient's medication list?
- AMagnesium hydroxide (Milk of Magnesia)
- BAluminum hydroxide/magnesium hydroxide (Maalox)
- CCalcium carbonate (Tums)
- DSodium bicarbonate (Alka-Seltzer)
Show answer & explanationAnswer & explanation
Correct answer: C. Calcium carbonate (Tums)
Many antacids can interact with warfarin. Aluminum and magnesium-containing antacids can decrease warfarin absorption. Sodium bicarbonate can cause metabolic alkalosis, which may potentiate warfarin's effect. Calcium carbonate generally has the least significant interaction with warfarin absorption and is often considered a safer choice among antacids, though separation of doses is always prudent.
Why the other options are wrong
- A. Magnesium hydroxide can decrease warfarin absorption due to chelation or altered pH.
- B. Aluminum hydroxide also decreases warfarin absorption, similar to magnesium hydroxide.
- D. Sodium bicarbonate can alter pH and potentially increase warfarin's effect, leading to higher bleeding risk.
Warfarin-Antacid Interactions
Certain antacids can interact with warfarin, affecting its absorption or metabolism, potentially altering its anticoagulant effect and increasing bleeding risk.
- Aluminum/Magnesium antacids can decrease warfarin absorption.
- Sodium bicarbonate can potentiate warfarin.
- Calcium carbonate generally has minimal interaction, but dose separation is advised.
Memory trick: Warfarin's Worst with Mixes; Calcium's Calmest.