The nurse is administering sevelamer during lunch to a client with chronic kidney disease (CKD). The client asks the nurse to bring the medication later. The nurse should describe which action of sevelamer as an explanation for taking it with meals?

Choice A reason: Hard candy can be used for a dry mouth, which is a common side effect of St. John's wort.

Choice B reason: Another form of contraception is needed, because St. John's wort can reduce the effectiveness of oral contraceptives and increase the risk of unplanned pregnancy. This information requires further instruction from the nurse.

Choice C reason: Insomnia may occur while taking the medication, which is another possible side effect of St. John's wort. The client should be advised to take the medication in the morning or afternoon, and avoid caffeine and alcohol.

Choice D reason: Sensitivity to the sun can develop, which is a rare but serious side effect of St. John's wort. The client should be instructed to wear sunscreen and protective clothing when exposed to sunlight.

Choice A reason: Promoting stomach emptying and preventing gastric reflux is not a relevant action of sevelamer, which is a phosphate binder that lowers serum phosphate levels in patients with CKD. Gastric reflux may be caused by other factors, such as hiatal hernia, obesity, or spicy foods.

Choice B reason: Buffering hydrochloric acid and preventing gastric erosion is not a pertinent action of sevelamer, which does not affect gastric acidity or mucosal integrity. Gastric erosion may be caused by other factors, such as NSAIDs, alcohol, or Helicobacter pylori infection.

Choice C reason: Preventing indigestion associated with ingestion of spicy foods is not a significant action of sevelamer, which does not affect digestion or food tolerance. Indigestion may be caused by other factors, such as overeating, stress, or gallstones.

Choice D reason: Binding with phosphorus in foods and preventing absorption is the correct action of sevelamer, which should be taken with meals to reduce the amount of phosphorus that enters the bloodstream from the diet. High serum phosphate levels can cause bone loss, calcification of soft tissues, and secondary hyperparathyroidism in patients with CKD.