Statins
Verified · Jul 2026Prototype: atorvastatin
HMG-CoA reductase inhibitors. Recognizable by the generic stem -statin.
How it works in the body
The system involved, what goes wrong, and how the drug and body interact.
01 Cholesterol, LDL, and how arteries clog
Cholesterol is essential — it builds cell membranes and hormones — but it travels through blood packaged in particles. LDL ("bad") cholesterol delivers cholesterol *to* tissues; HDL ("good") carries it back to the liver. When there is too much LDL, it seeps into artery walls, is oxidized, and is swallowed by immune cells to form fatty plaque — the disease called atherosclerosis.
Plaque narrows arteries and, more dangerously, can rupture — triggering a clot that causes a heart attack or stroke. Lowering LDL both slows plaque growth and makes existing plaque more stable (less likely to rupture). That is the whole therapeutic goal.
02 The liver’s cholesterol assembly line
Most cholesterol isn’t eaten — it’s manufactured by the liver. The production line runs from a building block (HMG-CoA) through a series of steps to cholesterol, and the rate-limiting step — the slowest, controlling valve of the whole line — is an enzyme called HMG-CoA reductase.
Whoever controls that enzyme controls how much cholesterol the liver makes. That is exactly where statins act.
03 How statins intervene
A statin competitively blocks HMG-CoA reductase, so the liver makes less cholesterol internally. Sensing it now has too little, the liver cell responds by building more LDL receptors on its surface and pulling LDL out of the bloodstream to compensate.
That second step is the key: it isn’t just that the liver makes less — it actively clears circulating LDL, which is what lowers the number on the lab report. Because the liver makes most of its cholesterol at night, short-acting statins work best dosed in the evening.
04 How the body reacts — the muscle, glucose, and liver effects
The same mevalonate pathway statins block also makes molecules muscle cells rely on, which is thought to underlie the class’s hallmark side effect: muscle symptoms, ranging from mild aches to — rarely — rhabdomyolysis, where muscle breaks down and releases myoglobin that can injure the kidneys. Risk climbs with high doses, interacting drugs (that raise statin levels), advanced age, and kidney impairment.
Statins also modestly raise blood glucose (a small increase in new-onset diabetes) and can bump liver enzymes. These are monitored but rarely outweigh the large cardiovascular benefit.
05 Beyond statins — the non-statin add-ons
Statins are first-line, but when LDL is still too high (or statins aren’t tolerated) several non-statin drugs are added on. Ezetimibe (Zetia) blocks the intestinal cholesterol transporter NPC1L1, cutting absorption of dietary/biliary cholesterol — a modest ~13–20% LDL drop that pairs well with a statin. The PCSK9 inhibitors — the injectable monoclonal antibodies alirocumab and evolocumab (the "-mab" drugs), plus the siRNA inclisiran — stop the liver from destroying its own LDL receptors, so more receptors clear more LDL, dropping it by up to ~60% for high-risk patients.
Fibrates (fenofibrate, gemfibrozil) are a different tool: they activate PPAR-α to mainly lower triglycerides and raise HDL, used for very high triglycerides rather than LDL. The key nursing caution is overlap toxicity — fibrates (especially gemfibrozil) added to a statin raise the risk of myopathy/rhabdomyolysis, so the combination is used carefully. (Older bile-acid sequestrants and niacin are now less used.)
Drug names
Indications
- Hyperlipidemia (elevated LDL cholesterol)
- Primary & secondary prevention of atherosclerotic cardiovascular disease (ASCVD)
- Non-statin add-ons (ezetimibe, PCSK9 inhibitors, fibrates) — see the overview note
Mechanism of action
Competitively inhibit HMG-CoA reductase, the rate-limiting enzyme of hepatic cholesterol synthesis — upregulating LDL receptors and lowering circulating LDL; also stabilize atherosclerotic plaque.
Therapeutic effects — what you'll see working
Statins are judged not by how a patient feels — the benefit is silent — but by the LDL number and long-term reduction in heart attacks and strokes. Effects on the lab panel appear within weeks; the cardiovascular payoff accrues over years.
- ↓ LDL cholesterol
- Upregulated liver LDL receptors clear LDL from the blood, typically lowering it 30–50% depending on the statin and dose. This is the primary, measurable effect.
- Plaque stabilization
- Beyond the number, statins make existing plaque less inflamed and less likely to rupture — which is why they cut heart-attack and stroke risk even when LDL is only modestly high.
Adverse effects
Most side effects trace to the mevalonate pathway the drug blocks — the same pathway supplies molecules muscle cells need — plus small metabolic effects on glucose and the liver.
Interactions
Contraindications
Because the liver both clears statins and is where they act, liver disease is the central concern; interactions matter because they raise statin blood levels into the myopathy range.
Labs & levels
Nursing considerations
The RN-specific layer — each action paired with the reason it matters.
Sources
- Atorvastatin — adverse effects, myopathy, contraindications — StatPearls (NCBI)
- Lipitor (atorvastatin) — FDA prescribing information — FDA
- Ezetimibe — NPC1L1 cholesterol-absorption inhibition, ~13–20% LDL reduction (non-statin note) — StatPearls (NCBI)
- PCSK9 Inhibitors — alirocumab/evolocumab/inclisiran, up to ~60% LDL reduction (non-statin note) — StatPearls (NCBI)
- Fibric Acid Antilipemic Agents — PPAR-α, triglyceride lowering, statin-combination myopathy risk — StatPearls (NCBI)
Educational summary for nursing students. Always verify against current prescribing information and your institution's protocols before administering. Not medical advice.