Which of the following statements is true regarding Nitrofurantoin (Macrodantin)?

The statement about Nitrofurantoin (Macrodantin) being effective only against bacteria in the urinary tract is accurate because Nitrofurantoin is primarily used to treat urinary tract infections (UTIs). The medication targets the bacteria responsible for these infections, making it particularly effective in that context. It acts by interfering with the production of bacterial proteins, DNA, and cell wall synthesis, which helps eliminate the infection within the urinary tract.

Other options, such as the treatment of infections in the bloodstream or the need for intravenous administration, are not applicable to Nitrofurantoin’s indicated use. Nitrofurantoin is not suitable for systemic infections or infections outside of the urinary tract, which reflects its specific mechanism of action and absorption characteristics. Additionally, it is not a broad-spectrum antibiotic that can be used for any infection, further validating why the correct statement is focused on its effectiveness specifically within the urinary system.