Niacin

VITAMIN B3

What it isNicotinic acid activating GPR109A; pellagra and, now rarely, dyslipidemia.

Why this oneIt raises HDL and lowers lipoprotein(a), but those lipid changes did not translate into added statin benefit.

What limits itFlushing commonly ends treatment; hepatotoxicity, hyperglycemia, and hyperuricemia require attention.

FDA-approved for

FDA dosing	Population	Start	Target	Max
Hyperlipidemia / hypertriglyceridemia	adult	500 mg QHS	1000–2000 mg QHS	2000 mg/day

Titration Increase by no more than 500 mg in any 4-week period

Renal Use with caution (not studied)

Hepatic Contraindicated in active liver disease or unexplained persistent transaminase elevations

Take at bedtime with a low-fat snack
Swallow whole; do not break, crush, or chew
Pretreat with aspirin (up to 325 mg) 30 min before to reduce flushing
Avoid alcohol, hot drinks, and spicy foods near dosing
Do not substitute for immediate-release or sustained-release niacin at equivalent doses
If therapy is interrupted for an extended period, restart with titration

Severe hepatotoxicity (especially substituting SR for IR niacin at equivalent doses)
Rhabdomyolysis/myopathy, increased with statins
Increased blood glucose
Reduced platelet count and increased PT
Increased uric acid (caution in gout)
Caution in unstable angina or acute MI

Pregnancy Discontinue in hyperlipidemia when pregnancy is recognized; assess individual risk/benefit in hypertriglyceridemia

Lactation Present in human milk; advise not to breastfeed during treatment

NO BOXED WARNINGS

Principal riskFlushing; no cardiovascular benefit added to a statin

Cost, est. cash$5–$150/month

Generic entry1992

Therapeutic safety burden1 / 4

Overdose danger1 / 4

Weight-gain liability0 / 4

Sedation liability0 / 4

QT / Torsades0 / 4

Direct muscarinic antagonism0 / 4

Embryofetal risk2 / 4

Legacy pregnancy categoryC

Defining liabilityMyopathy/rhabdomyolysis and hepatotoxicity; interaction burden varies by agent.