A nurse is teaching a client who has a new prescription for aluminum hydroxide to treat heartburn. The nurse should instruct the client to monitor for and report which of the following adverse reactions?

A. Flatulence: Flatulence (gas) is a common side effect of antacids like aluminum hydroxide. While it can be uncomfortable, it is not a serious adverse reaction that needs to be reported to the healthcare provider. B. Constipation: Aluminum hydroxide can cause constipation, which is a well-known side effect of aluminum-based antacids. This can be a more significant concern if it becomes severe or chronic, so the client should monitor for this and report it to the healthcare provider. C. Palpitations: Palpitations are not a common side effect of aluminum hydroxide. If the client experiences palpitations, it is more likely related to other causes, and the client should consult their healthcare provider, but it is not specifically linked to aluminum hydroxide. D. Headache: Headache is not a typical adverse reaction of aluminum hydroxide. Although headaches can be caused by many factors, including other medications, they are not a common or expected side effect of aluminum hydroxide.