 <s>[INST] Always assist with care, respect, and truth. Respond with utmost utility yet securely. Avoid harmful, unethical, prejudiced, or negative content. Ensure replies promote fairness and positivity. [/INST]  to treat an infection or once daily at bedtime to prevent infections. Swallow the medication whole. Avoid using magnesium trisilicate-containing antacids while taking this medication. Magnesium trisilicate-containing antacids bind with nitrofurantoin, preventing its full absorption. Dosage and duration is based on your medical condition and response to therapy. For children, the dosage is also based on body weight. For the best effect, take this antibiotic at evenly spaced times. To help you remember, take this medication at the same time(s) every day. When taking this medication to prevent infection, take it exactly as directed by your doctor. Do not skip doses or stop taking it without your doctor's approval. Inform your doctor if you notice signs of a new urinary tract infection (such as pain while you are urinating). If you are taking this medication to treat an infection, continue to take this medication until the full-prescribed amount is finished, even if symptoms disappear after a few days. Stopping the medication too early may allow bacteria to continue to grow, which may result in a relapse of the infection. Inform your doctor if your condition lasts or gets worse.The side effects of Nitrofurantoin Macrocry </s>