Which mineral interaction involves laxatives and the seizure medication phenytoin (dilantin)?

Which mineral interaction involves laxatives and the seizure medication phenytoin (dilantin)?

• A. Calcium
• B. Magnesium
• C. Potassium
• D. Iron

Answer: (A)

Calcium is the mineral involved. Laxatives that contain calcium can bind phenytoin in the gut, forming an insoluble complex that reduces phenytoin absorption. With less drug entering the bloodstream, seizure control can worsen, which is especially risky given phenytoin’s narrow therapeutic range and variable absorption. To minimize this interaction, separate the dosing of calcium-containing laxatives and phenytoin by several hours and monitor seizure control and drug levels. Other minerals can influence drug absorption in different contexts, but the classic interaction here is calcium binding with phenytoin and decreasing its absorption.

Calcium is the mineral involved. Laxatives that contain calcium can bind phenytoin in the gut, forming an insoluble complex that reduces phenytoin absorption. With less drug entering the bloodstream, seizure control can worsen, which is especially risky given phenytoin’s narrow therapeutic range and variable absorption. To minimize this interaction, separate the dosing of calcium-containing laxatives and phenytoin by several hours and monitor seizure control and drug levels. Other minerals can influence drug absorption in different contexts, but the classic interaction here is calcium binding with phenytoin and decreasing its absorption.