This medication must not be injected into a vein or mixed with solutions that will be injected into a vein.

Pain at the injection site, nausea, or vomiting may occur. If these effects last or get worse, tell your doctor or pharmacist promptly. Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects. Tell your doctor right away if you have any serious side effects, including: severe pain/peeling skin at injection site, joint/muscle pain, headache, vision changes, fast/slow/pounding heartbeat, numbness/tingling of arms/legs, pain/redness/swelling of arms/legs, change in skin color near injection site or on arms/legs, uncontrolled movements, inability to move, signs of kidney problems (such as change in the amount of urine), new signs of infection (such as sore throat that doesn't go away, fever), easy bruising/bleeding, dark/cloudy urine, seizures, mental/mood changes (such as depression, agitation). Get medical help right away if you have any very serious side effects, including: chest pain, trouble speaking, fainting. This medication has rarely caused a very serious (possibly fatal) blood disorder (methemoglobinemia). This effect is more likely if you have breathing problems, certain diseases of the blood, or if you smoke (see also Precautions section). The symptoms of this disorder may occur within minutes to a couple of hours after using this medication. Stop using this medication and get medical help right away if you develop any symptoms of methemoglobinemia, including: headache, confusion, dizziness, shortness of breath, tiredness, pale/bluish/gray skin, fast heartbeat. This medication may rarely cause a severe intestinal condition due to a bacteria called C. difficile. This condition may occur during treatment or weeks to months after treatment has stopped. Tell your doctor right away if you develop: diarrhea that doesn't stop, abdominal or stomach pain/cramping, blood/mucus in your stool. If you have these symptoms, do not use anti-diarrhea or opioid products because they may make symptoms worse. Use of this medication for prolonged or repeated periods may result in oral thrush or a new vaginal yeast infection. Contact your doctor if you notice white patches in your mouth, a change in vaginal discharge, or other new symptoms. A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing. This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist. In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch. In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

A product that may interact with this drug is: methotrexate. This medication may interfere with certain lab tests (such as certain urine glucose tests), possibly causing false test results. Make sure lab personnel and all your doctors know you use this drug.