Niacin Drug Interactions
There are several drugs and medications which when used with niacin and its derivatives can cause a moderate to severe interaction.
If you are currently taking or normally take any of the following drugs, do not start using niacin without consulting your healthcare provider.
Significant Drug Interactions
Some of the drugs that can cause significant interactions with niacin include the following:
Certain Antibiotics – B-complex supplements, including niacin, affect the absorption and effectiveness of the antibiotic tetracycline, as such concomitant use of these medications is not advised.
- Tetracycline (Sumycin)
Anticoagulant drugs – Niacin potentiates the effects of blood thinners, increasing the risk of bleeding. When taken together, bleeding time should be closely monitored.
- Warfarin (Coumadin, Jantoven)
Antihypertensive Therapy – Niacin increases the effects of antihypertensive drugs, particularly of ganglionic blocking agents and vasoactive drugs. This drug interaction can lead to abnormally low blood pressure and increases the risk of postural hypotension.
Alpha blockers, such as:
- Alfuzosin (Uroxatral)
- Carvedilol (Coreg)
- Doxazosin (Cardura)
- Labetalol (Trandate)
- Phenoxybenzamine (Dibenzyline)
- Phentolamine (Regitine)
- Prazosin (Minipress)
- Tamsulosin (Flomax)
- Terazosin (Hytrin)
Beta blockers, such as:
- Atenolol (Tenormin)
- Bisoprolol (Zebeta)
- Metoprolol (Lopressor)
- Nadolol (Corgard)
- Propranolol (Inderal)
- Sotalol (Betapace)
- Timolol (Blocadren)
- Carvedilol (Coreg)
- Labetalol (Trandate)
Calcium channel blockers, such as:
- Amlodipine (Norvasc)
- Diltiazem (Cardizem)
- Felodipine (Plendil)
- Isradipine (Dynacirc)
- Nisoldipine (Sular)
- Nicardipine (Cardene)
- Nifedipine (Adalat, Procardia)
- Nimodipine (Nimotop)
- Verapamil (Calan, Isoptin, Verelan)
Aspirin – Aspirin interferes with the excretion of nicotinic acid although its clinical significance is unclear. Aspirin may also help minimize flushing due to niacin, but should only be taken under medical supervision.
Bile Acid Sequestrants – These cholesterol lowering drugs may decrease the effectiveness of niacin. As such, should be taken at different times of the day or at least 4 to 6 hours before or after taking niacin.
- Cholestyramine (Prevalite, Questran)
- Colesevelam (WelChol)
- Colestipol (Colestid)
Diabetes medications – Niacin may increase blood sugar levels. People taking diabetes medications together with niacin should closely monitor their blood glucose levels. Dose adjustments for each drug may be necessary.
- Glipizide (Glucotrol)
- Glyburide (Diabeta, Micronase)
- Metformin (Apo-Metformin, Glucophage)
Nicotine patches – Concomitant use of nicotine patches and niacin may worsen or increase the risk of niacin flush, as such should be avoided.
Nitrates – As with most antihypertensive drugs, using niacin together with nitrates could lead to abnormally low blood pressure.
- Isosorbide dinitrate (Isordil)
- Isosorbide mononitrate (Imdur, Ismo, Monoket)
Statins – High doses of niacin (greater than 1 gm/day), when taken with statins (also known as HMG-COA reductase inhibitors), increases the risk of severe side effects, such as myopathy and rhabdomyolysis. Caution should be taken when using these drugs together. When using these drugs in combination, the daily dose of niacin should not exceed 2000 mg while statin dose should be kept at 40 mg.
- Atorvastatin (Lipitor) or other drugs containing atorvastatin
- Fluvastatin (Lescol)
- Lovastatin (Altoprev, Mevacor) or other drugs containing lovastatin
- Pitavastatin (Livalo)
- Pravastatin (Pravachol)
- Rosuvastatin (Crestor)
- Simvastatin (Zocor) or other drugs containing simvastatin
Niacin can also affect results of certain lab tests such as urinary or blood cathecolamine determination and urine glucose tests, particularly those that use Benedict’s reagent. Inform your laboratory personnel and all healthcare providers about your use of this medication.
Lastly, this document may not contain all the drugs that can potentially interact with niacin. Therefore, be sure to discuss with your healthcare provider all the medications that you currently and normally take. Make a list of all drugs that you take and share it with your doctor.