A nurse is providing teaching to a client who has renal failure and an elevated phosphorous level. The provider instructed the client to take aluminium hydroxide 300 mg PO three times daily. For which of the following adverse effects should the nurse inform the client?

A. Muscle spasms: Muscle spasms are more commonly associated with hypocalcemia or electrolyte imbalances rather than the use of aluminum hydroxide. While clients with renal failure may experience spasms due to their condition, this is not a primary adverse effect. B. Constipation: Aluminum hydroxide is known to cause constipation as a common adverse effect because it neutralizes stomach acid and slows gastrointestinal motility. Teaching the client to expect and manage constipation, such as increasing fluid and fiber intake if permitted, is essential. C. Headache: Headaches are not a typical adverse effect of aluminum hydroxide. While clients may experience them due to other conditions, they are not specifically related to this phosphate-binding medication. D. Metallic taste: Aluminum hydroxide can cause minor gastrointestinal disturbances, but a metallic taste is uncommon. It is not considered a primary adverse effect that requires patient teaching for routine therapy.