A nurse is caring for a client who has osteoporosis and is taking calcium carbonate. The nurse should monitor the client for which of the following adverse effects?

A. Tinnitus is not a known adverse effect of calcium carbonate; it is more commonly associated with ototoxic drugs (e.g., high-dose salicylates, aminoglycosides). B. Urinary retention is not typically caused by calcium carbonate. C. Flank pain can indicate renal calculi or nephrolithiasis from hypercalcemia or increased urinary calcium excretion — a potential adverse effect of excessive calcium supplementation. This finding should be monitored and reported. D. Bradycardia is not a common adverse effect of calcium carbonate.