Niacin

Flushing of the face and neck along with warmth, headache, itching, burning, sweating, chills, or tingling may occur within 20 minutes of taking this medication. Flushing may last for a few hours after use. These effects should improve or go away as your body adjusts to the medication. Dizziness, stomach upset, heartburn, nausea, vomiting, and diarrhea may also occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.

To reduce the risk of dizziness and lightheadedness, get up slowly when rising from a sitting or lying position. This is very important if you are also taking medication to lower your blood pressure.

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: nausea/vomiting that doesn't stop, fast/irregular heartbeat, severe headache (migraine), unusual joint pain, swelling of legs/arms, vision problems, severe stomach/abdominal pain, black stools, easy bruising/bleeding, unexplained muscle pain/tenderness/weakness, signs of kidney problems (such as change in the amount of urine), dark urine, vomit that looks like coffee grounds, yellowing eyes/skin.

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 MedWatch: The FDA Safety Information and Adverse Event Reporting Program.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Before taking niacin, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: very low blood pressure, alcohol use, bleeding problems (such as low platelets), diabetes, gallbladder disease, glaucoma, gout, heart disease (such as recent heart attack, unstable angina), kidney disease, liver disease/increase in liver enzymes, untreated mineral imbalance (low phosphate levels), stomach/intestinal ulcers, underactive thyroid (hypothyroidism).

This drug may make you dizzy. Alcohol or marijuana (cannabis) can make you more dizzy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

This medication may rarely make your blood sugar rise, which can cause or worsen diabetes. If you already have diabetes, check your blood sugar regularly as directed and share the results with your doctor. Tell your doctor right away if you have symptoms of high blood sugar such as increased thirst/urination. Your doctor may need to adjust your diabetes medication, exercise program, or diet.

During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.

This medication passes into breast milk. Consult your doctor before breastfeeding.

See also How to Use section.

Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

Check all prescription and nonprescription medicine labels carefully since vitamins/dietary supplements may also contain niacin or niacinamide (nicotinamide). These may increase your risk of side effects if taken together. Ask your doctor or pharmacist for more details.

This medication may interfere with certain lab tests (such as urine or blood catecholamines, copper-based urine glucose tests), possibly causing false test results. Make sure lab personnel and all your doctors know you use this drug.

If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call 1-800-222-1222. Canada residents can call 1-844-764-7669.

Do not share this medication with others.

Lab tests (such as blood lipids, blood sugar, liver function) should be done while you are taking this medication. Keep all medical and lab appointments. Consult your doctor for more details.

If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.

Store at room temperature away from light and moisture. Do not store in the bathroom. Keep all medications away from children and pets.

Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.