Following are the common symptoms observed in the patients using Niaspan: Dryness of the mouth, Headache, Migraine, Redness of face If you observe any of the following side effects contact your doctor as soon as possible or seek medical help: Flushing, Bloating, Blurred vision, Abnormal heart rhythm, Impaired or dim vision, Inflammation of the liver, Gastric irritation, Elevated serum aspartate transaminase, Severe itching of the skin, Diarrhea, Hepatic failure, Urticaria, Cramps, Hyperpigmentation of the skin, Pain in a muscle or group of muscles, Headache, Ichthyosis, Fainting, Joint pain, Muscle pains or weakness, Severe headache (migraine), Signs of clotting problems (unusual nosebleeds, bruising, blood in urine, coughing blood, bleeding gums, cuts that don’t stop bleeding), Signs of liver problems (yellow eyes or skin, abdominal pain, dark urine or pale stools, nausea, vomiting), Irregular heartbeat, Rash, Ringing in the ears, Sweating, Tiredness, Vomiting, Weakness