The nurse is admitting a patient to the acute care floor. While obtaining the history, the client tells the nurse she is allergic to penicillin. Which of the following medications, if ordered by the physician, would be safe for this client?

A. Diarrhea: Diarrhea is a common side effect of antibiotics due to their effect on the gut microbiota, but it is not typically indicative of an allergy.
B. Hives or shortness of breath: Hives (urticaria) and shortness of breath are classic symptoms of an allergic reaction. Hives indicate an immediate hypersensitivity reaction, and shortness of breath can indicate a serious allergic reaction such as anaphylaxis. These symptoms warrant caution and further assessment before starting antimicrobial therapy.
C. Headaches: Headaches can be a side effect of various medications but are not a specific sign of a drug allergy.
D. Nausea: Nausea is a common side effect of many medications, including antibiotics, but it does not specifically indicate an allergic reaction.

A. The patient may choke: This is not the primary concern for extended-release medications like metformin (Glucophage XL). While choking is a risk with any pill, it's not specific to the need for avoiding crushing or chewing extended-release formulations.
B. It would cause blood glucose levels to rise too rapidly: Crushing or chewing the medication would not cause blood glucose levels to rise rapidly. Instead, it could lead to a more rapid release and absorption of the drug, which might lower blood glucose too quickly, potentially leading to hypoglycemia.
C. Irritation of the oral mucosa may occur: While irritation of the oral mucosa could be a concern with some medications, it is not the primary reason for avoiding the crushing or chewing of extended-release formulations like Glucophage XL.
D. The effect of the medication may be changed: Crushing or chewing an extended-release tablet disrupts its formulation. Glucophage XL is designed to release metformin slowly over time. If the tablet is crushed or chewed, it can result in the entire dose being released at once, which can alter the intended pharmacokinetics and pharmacodynamics of the drug. This could lead to a higher risk of side effects and a loss of the extended-release benefit, ultimately changing the medication's effect and possibly leading to issues like hypoglycemia or gastrointestinal side effects.