A nurse is providing teaching to a client who has a new prescription for tetracycline. The nurse should instruct the client to avoid taking which of the following supplements with tetracycline?

A. Folic acid: Folic acid supplementation does not interfere with tetracycline absorption or effectiveness. It is safe to take concurrently without affecting antibiotic action. B. Calcium carbonate: Calcium binds with tetracycline in the gastrointestinal tract, forming an insoluble complex that reduces absorption and decreases the antibiotic’s effectiveness. Clients should avoid calcium supplements, dairy products, or antacids containing calcium when taking tetracycline. C. Vitamin C: Vitamin C does not interact significantly with tetracycline. It can be taken safely without reducing the medication’s absorption or therapeutic effects. D. Fish oil: Fish oil supplements do not interfere with tetracycline metabolism or absorption. They can be continued as part of the client’s routine supplement regimen.