Mechanism of Action

Inhibit HMG-CoA reductase, the rate-limiting enzyme in hepatic cholesterol synthesis. With synthesis blocked, the liver upregulates LDL receptors and pulls more LDL out of the blood — a 30–50%+ reduction in LDL-C depending on agent and intensity. Beyond lipid lowering, statins stabilize atherosclerotic plaque by reducing arterial-wall inflammation, which is why they are started immediately after acute coronary syndrome, not just for chronic hyperlipidemia. Short-acting agents (simvastatin, fluvastatin) are dosed in the evening because hepatic synthesis peaks overnight; long-acting agents (atorvastatin, rosuvastatin) can be taken any time of day.

Common Medications

atorvastatinPrototype

long-acting — dosed any time of day

rosuvastatin

long-acting — any time of day

simvastatin

short-acting — evening dosing; highest grapefruit-juice interaction

pravastatin

fluvastatin

short-acting — evening dosing

Indications

clinical ASCVD

atherosclerotic cardiovascular disease

acute coronary syndrome

started immediately for plaque stabilization, regardless of baseline LDL

LDL ≥ 190 mg/dL

diabetes mellitus, ages 40–75

elevated 10-year ASCVD risk

Side Effects

myalgia

muscle aches WITHOUT CK elevation; most common reason clients stop therapy — but still report it to rule out progression

new-onset hyperglycemia

class effect — raises blood glucose / new-onset diabetes risk

reversible memory impairment

FDA-acknowledged, reversible cognitive effect

Contraindications & Interactions

Contraindications

pregnancy

teratogenic — use reliable contraception in clients of childbearing age

active liver disease

Interactions

grapefruit juice

CYP3A4 inhibition raises statin levels and myopathy risk — especially simvastatin and atorvastatin

fibrates

gemfibrozil — additive myopathy risk

macrolide antibiotics

CYP3A4 inhibition raises statin levels

azole antifungals

raise statin levels

Administration & Monitoring

obtain baseline fasting lipid panel

obtain baseline liver function tests

ALT/AST before initiation

recheck lipids 4–12 weeks after starting or adjusting

effectiveness = LDL decreased from baseline; maximal effect ~4–6 weeks

evening dosing for short-acting agents

simvastatin, fluvastatin — hepatic synthesis peaks overnight; long-acting agents any time

check CK for muscle complaints

if myopathy is suspected

assess renal function if rhabdomyolysis is suspected

BUN, creatinine

Patient Teaching

report unexplained muscle pain or weakness promptly

do not wait for the next scheduled visit

report dark or cola-colored urine

possible rhabdomyolysis

avoid grapefruit juice

especially with simvastatin and atorvastatin

continue diet and exercise

lifestyle changes are not replaced by the drug

use reliable contraception

statins are teratogenic

do not expect immediate cholesterol change

maximal LDL reduction takes ~4–6 weeks, not the first week

take long-acting agents at a consistent daily time

atorvastatin/rosuvastatin any time; short-acting in the evening

Report Nowescalate immediately

rhabdomyolysis Hallmark

massive muscle breakdown releasing myoglobin → acute kidney injury; cola-colored urine is rhabdomyolysis until proven otherwise — hold the statin, check CK and renal function (BUN/creatinine), notify the provider immediately

myopathyCK > 10× ULN

muscle weakness with CK > 10× upper limit of normal — the step between myalgia and rhabdomyolysis

hepatotoxicity

monitor ALT/AST; this pathway uses LFTs, NOT CK

Clinical Pearl

Cola-colored urine on a statin is rhabdomyolysis until proven otherwise — stop the drug, check CK and renal function, and notify the provider. Muscle pathway uses CK; the liver pathway uses LFTs — two separate monitors, not one.