Pharmacology & Drug-Nutrient Interactions Flashcards

Long-term use of combined oral contraceptives is most commonly associated with depletion of which nutrient, with implications for women planning pregnancy?

Answer: Folate

Oral contraceptives increase folate metabolism and urinary excretion; adequate folate status is critical before conception to prevent neural tube defects.

Chronic alcohol abuse impairs the activation of which vitamin primarily through its effects on hepatic hydroxylation?

Answer: Vitamin D

Alcohol impairs the liver's ability to perform 25-hydroxylation of vitamin D, the first essential step in producing the active hormonal form, leading to metabolic bone disease.

Long-term use of aluminum-containing antacids can deplete which mineral by forming insoluble complexes in the gastrointestinal tract?

Answer: Phosphate

Aluminum hydroxide binds dietary phosphate in the gut forming insoluble aluminum phosphate, reducing phosphate absorption and potentially causing hypophosphatemia.

The antibiotic trimethoprim reduces availability of which nutrient by competitively inhibiting the enzyme dihydrofolate reductase?

Answer: Folate

Trimethoprim inhibits dihydrofolate reductase, the enzyme required to convert dietary folate into its active tetrahydrofolate form needed for DNA synthesis.

Cyclosporine, an immunosuppressant used after organ transplantation, causes wasting of which electrolyte through nephrotoxic effects on the renal tubules?

Answer: Magnesium

Cyclosporine causes renal tubular dysfunction that impairs magnesium reabsorption, leading to hypomagnesemia which can manifest as muscle cramps, tremors, and cardiac arrhythmias.

High-dose aspirin therapy can deplete which vitamin by increasing its renal tubular excretion?

Answer: Vitamin C

High-dose salicylates compete with vitamin C for renal tubular reabsorption and increase its urinary excretion, potentially contributing to deficiency with chronic use.

Patients prescribed lithium for bipolar disorder require which specific dietary modification to prevent toxicity, since lithium and this nutrient share renal reabsorption mechanisms?

Answer: Consistent sodium intake

Sodium and lithium are reabsorbed by the same renal tubular mechanism; sodium depletion (from low-sodium diets or diuretics) causes compensatory lithium retention, increasing toxicity risk.