Some of these side effects may occur when taking this medication; they are as follows; Nausea, vomiting, loss of appetite, or headache may occur. However if any of these effects persist or worsen, contact your doctor right away.
This medication may cause your urine to turn dark yellow or brown in color. This effect is harmless and will disappear when the medication is stopped.
This medication may rarely cause very serious (possibly fatal) lung problems. Lung problems may occur within the first month of treatment or after long-term use of nitrofurantoin (generally for 6 months or longer). Get medical help right away if you develop symptoms of lung problems, including: persistent cough, chest pain, shortness of breath/trouble breathing, joint/muscle pain, bluish/purplish skin.
Tell your doctor right away if you have any serious side effects, including: new signs of infection (e.g., fever, persistent sore throat), easy bruising/bleeding, mental/mood changes, persistent or severe headaches, vision changes.
Tell your doctor right away if any of these rare but very serious side effects occur: persistent nausea/vomiting, dark urine, yellowing of eyes/skin, unusual/persistent fatigue, fast/pounding heartbeat, numbness/tingling of the arms/legs, muscle weakness.
This medication may rarely cause a severe intestinal condition (Clostridium difficile-associated diarrhea) due to resistant bacteria. This condition may occur during treatment or even weeks to months after treatment has stopped. Do not use anti-diarrhea or opioid medications if you have the following symptoms because these products may make them worse. Tell your doctor right away if you develop: persistent diarrhea, abdominal or stomach pain/cramping, blood/mucus in your stool.