Get emergency medical help if you have any of these signs of an allergic reaction to Niaspan ER: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
Call your doctor at once if you have any of these serious side effects:
feeling like you might pass out;
fast, pounding, or uneven heart beats;
feeling short of breath;
swelling;
jaundice (yellowing of your skin or eyes); or
muscle pain, tenderness, or weakness with fever or flu symptoms and dark colored urine.
If you are diabetic, tell your doctor about any changes in your blood sugar levels.
Less serious Niaspan ER side effects include:
mild dizziness;
warmth, redness, or tingly feeling under your skin;
itching, dry skin;
sweating or chills;
nausea, diarrhea, belching, gas;
muscle pain, leg cramps; or
sleep problems (insomnia).
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
 Niaspan side effects (more detail)
