Slight burning, tingling, or stinging may occur. If any of these effects persist or worsen, contact your doctor or pharmacist promptly.
If your doctor has directed you to use this medication, remember that he or she 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.
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, unusual anxiety, dizziness, shortness of breath, tiredness, pale/bluish/gray skin, fast heartbeat.
A very serious allergic reaction to this drug is rare. However, seek immediate medical attention 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.
In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.