Niacin

Nicotinic acid, Vitamin B3

Mechanism :

It is a vitamin B compound used as a nutritional supplement. It is used in the treatment of pellagra characterized by dermatitis, diarrhea and dementia. It is also used in the treatment of Hartnup disease.
Niacin binds to Nicotinate D-ribonucleotide pyrophosphate phosphoribosyltransferase, Nicotinic acid phosphoribosyltransferase, Nicotinate N-methyltransferase and the Niacin receptor. Niacin is the precursor to nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP), which are vital cofactors for dozens of enzymes. The mechanism by which niacin exerts its lipid lowering effects is not entirely understood, but may involve several actions, including a decrease in esterification of hepatic triglycerides. Niacin treatment also decreases the serum levels of apolipoprotein B-100 (apo B), the major protein component of the VLDL (very low-density lipoprotein) and LDL fractions.

Indication :

• Adjunctive treatment for type IV and V Dyslipidemia
• Nutritional supplementation
• Pellagra

Contraindications :

Hypersensitivity, Active peptic ulcer, Arterial bleeding, Active Hepatic disease, unexplained elevated LFTs.

Caution if hepatic disease hx, biliary disease hx, PUD hx, alcohol abuse, diabetes mellitus or risk, gout, unstable angina, acute MI, renal impairment, hypophosphatemia, surgery.

Dosing :

Adverse Effect :

Flushing, heat, itching, dyspepsia, headache, dizziness, arrhythmias, abdominal pain, hepatotoxicity.

Interaction :

Colesevelam Bile Acid Sequestrants: May decrease the absorption of Niacin. It may be prudent to separate the administration times of niacin and bile acid sequestrants by a few hours in order to reduce the potential for reduced efficacy of these agents. The manufacturer of colesevelam recommends that drugs should be administered at least 1 hour before or 4 hours after colesevelam.
Lovastatin: Risk of severe myopathy/rhabdomyolysis with this combination.
Pitavastatin: Increased incidence of adverse drug reactions (i.e. rhabdomyolysis) of both niacin and Pitavastatin via pharmacodynamic synergism. Use alternative therapy.

Renal Dose :

Hepatic Dose :