Also known as niacin,
nicotinic acid is a water-soluble vitamin that decreases cholesterol,
triglyceride, and apolipoprotein B-100 levels and increases the HDL level. The
drug is available in immediate-release and extended-release tablets.
Nicotinic acid is rapidly and extensively absorbed
following oral administration. It’s moderately bound to plasma proteins; its
over-all binding ranges from 60% to 70%. The drug undergoes rapid me-tabolism
by the liver to active and inactive metabolites. About 75% of the drug is
excreted in urine.
The mechanism of action by which nicotinic acid
lowers triglyc-eride and apolipoprotein levels is unknown. However, it may work
by inhibiting hepatic synthesis of lipoproteins that contain apolipoprotein
B-100, promoting lipoprotein lipase activity, reduc-ing free fatty acid
mobilization from adipose tissue, and increasing fecal elimination of sterols.
Nicotinic acid is usually used in combination with
other drugs to lower triglyceride levels in patients with type IV or V
hyperlipi-demia who are at high risk for pancreatitis and to lower choles-terol
and LDL levels in patients with hypercholesterolemia. It may also be used with
other antilipemics to boost HDL levels.
Nicotinic acid is contraindicated in patients who
are hypersen-sitive to nicotinic acid and in those with hepatic dysfunction,
ac-tive peptic ulcer disease, or arterial bleeding.
Together, nicotinic acid and an HMG-CoA reductase inhibitor may increase
the risk of myopathy or rhabdomyolysis.
(cholestyramine, colesevelam, and colestipol) can bind with nicotinic acid and
decrease its effective-ness.
When given with
nicotinic acid, kava may increase the risk of hepatotoxicity. (See Adverse reactions to nicotinic acid.)