A nurse is reviewing the orders of a newly admitted client who has a prescription for a fentanyl transdermal patch for severe pain. Which new prescription should the nurse be concerned about causing a serious drug-drug interaction?

A. Hypoglycemia is a common side effect: Repaglinide is a meglitinide that stimulates rapid, short-acting insulin release from pancreatic beta cells, increasing the risk of hypoglycemia, especially if meals are skipped or delayed. Client education should emphasize recognizing early signs, carrying a source of glucose, and timing doses with meals to prevent severe hypoglycemia.

B. Bruising may occur when taking this medication: Bruising is not a typical side effect of repaglinide. Unlike anticoagulants or antiplatelet agents, repaglinide does not affect platelet function or clotting pathways, so clients do not need to monitor for unusual bruising as part of routine education.

C. Take this medication at night before bed: Repaglinide should be taken with meals, usually 0–30 minutes before eating, to match insulin secretion with postprandial glucose. Taking it at night without food increases the risk of hypoglycemia, particularly during prolonged fasting or sleep.

D. Stop taking if you experience hyperglycemia: Experiencing high blood glucose does not warrant abrupt discontinuation of repaglinide. Instead, the client should notify the healthcare provider for dose adjustment or evaluation of adherence, diet, or additional therapy while continuing the medication safely.

A. Diarrhea: Gastrointestinal upset, including diarrhea, is a common and generally mild side effect of metformin. While uncomfortable, it is usually self-limiting and does not indicate a life-threatening condition.

B. Shallow breathing: Shallow or labored breathing is concerning because it may indicate lactic acidosis, a rare but potentially fatal complication of metformin. Lactic acidosis occurs due to accumulation of lactate when metformin impairs mitochondrial gluconeogenesis, requiring immediate medical evaluation.

C. Nausea: Nausea is a common gastrointestinal side effect of metformin. While it may contribute to dehydration or decreased oral intake, it is usually manageable and does not require emergent intervention unless severe.

D. Metallic taste: A metallic taste in the mouth is a minor and non-life-threatening side effect of metformin. It does not pose significant health risks and is not typically a cause for urgent concern.