Ezetimibe / Simvastatin

Ezetimibe/simvastatin is a combination cholesterol-lowering medication used across two products — Ezetimibe and Simvastatin tablets and Vytorin — for the following conditions:

• High cholesterol (primary hyperlipidemia — both genetic and non-genetic) in adults: lowers LDL, total cholesterol, triglycerides, apolipoprotein B, and non-HDL cholesterol, and raises HDL cholesterol
• Mixed hyperlipidemia (elevated cholesterol and triglycerides together) in adults
• Homozygous familial hypercholesterolemia (HoFH) — a severe inherited cholesterol disorder — as an add-on to other cholesterol-lowering treatments
• Vytorin specifically: heterozygous familial hypercholesterolemia (HeFH) in adults and children aged 10 and older
• Vytorin specifically (via its simvastatin component): reducing the risk of coronary heart disease death, non-fatal heart attack, stroke, and the need for heart procedures in high-risk adults with established coronary heart disease, cerebrovascular disease, peripheral vascular disease, and/or diabetes

Ezetimibe/simvastatin tackles high cholesterol from two directions at once. Ezetimibe blocks a protein in the small intestine wall called NPC1L1, which normally shuttles cholesterol from your food into your bloodstream — reducing intestinal cholesterol absorption by roughly half. Simvastatin works in the liver, blocking an enzyme called HMG-CoA reductase that is essential for the liver's own cholesterol production. With less cholesterol coming in from the gut and less being made in the liver, the liver responds by pulling more LDL ('bad') cholesterol out of the blood, lowering overall levels.

Simvastatin also lowers triglycerides and raises HDL ('good') cholesterol. Because the two drugs work through different pathways, they complement each other and produce greater cholesterol reduction together than either would alone.

Both Ezetimibe and Simvastatin tablets and Vytorin are taken once daily by mouth in the evening, with or without food. Your prescriber will determine the right dose based on your cholesterol goals, other medical conditions, and any other medications you take — do not adjust your dose on your own. If you miss a dose, take it as soon as you remember; do not take two doses at once to make up for a missed one.

• If you take a bile acid sequestrant (a separate type of cholesterol medication), take this combination at least 2 hours before or 4 hours after it to avoid an absorption interaction
• Avoid grapefruit juice while taking this medication, as it can raise simvastatin levels in your blood
• Your doctor may check your cholesterol levels within a few weeks of starting or adjusting your dose

The most commonly reported side effects include:

• Headache
• Muscle aches or pain (myalgia)
• Diarrhea
• Upper respiratory tract infection
• Elevated liver enzymes on blood tests
• Influenza symptoms
• Pain in the arms or legs
• Fatigue (reported with ezetimibe)

More serious reactions that need prompt medical attention include significant muscle pain or weakness (which could signal rhabdomyolysis — a dangerous muscle breakdown), signs of liver problems like yellowing skin or eyes, and a rare autoimmune muscle condition (IMNM) where weakness persists after stopping the drug. Call your doctor right away if you notice any of these.

• Muscle damage (myopathy and rhabdomyolysis): The most significant risk. Ranges from muscle pain and weakness to severe muscle breakdown that can cause kidney failure and, rarely, death. Risk is higher at higher doses, in adults 65+, women, people with kidney disease or uncontrolled hypothyroidism, and when taken with certain other medications. Stop the medication and call your doctor immediately if you have unexplained muscle pain, weakness, or tenderness — especially with fever, malaise, or dark urine.
• Immune-mediated necrotizing myopathy (IMNM): A rare autoimmune muscle condition linked to statins where muscle weakness and elevated muscle enzymes persist even after stopping the drug. May require immunosuppressive treatment.
• Liver enzyme elevations: Liver enzymes should be checked before starting treatment. Rare but serious liver failure has been reported with statins. Tell your doctor immediately if you develop yellowing of the skin or eyes, dark urine, or severe abdominal pain.
• Drug interactions: Several common medications dramatically raise the risk of muscle damage when combined with simvastatin — some are outright contraindicated. Always give your pharmacist and doctor a full list of everything you take.
• Pregnancy: This medication is contraindicated in pregnancy and breastfeeding. Use effective contraception if you are of childbearing age.

Ezetimibe/simvastatin has several important drug and food interactions, many of which significantly raise the risk of serious muscle damage:

• Strong antifungals (itraconazole, ketoconazole, posaconazole, voriconazole) — contraindicated: Block the enzyme that breaks down simvastatin, causing dangerous build-up
• Certain antibiotics (erythromycin, clarithromycin, telithromycin) — contraindicated: Same mechanism; must not be combined
• HIV/HCV protease inhibitors and cobicistat-containing products — contraindicated: Greatly raise simvastatin blood levels
• Gemfibrozil, cyclosporine, danazol — contraindicated: Sharply increase risk of rhabdomyolysis
• Verapamil, diltiazem, dronedarone — dose must be limited: Raise simvastatin levels; maximum dose is capped
• Amiodarone, amlodipine, ranolazine — dose must be limited: Increase muscle damage risk; maximum dose is capped
• Grapefruit juice — avoid: Raises simvastatin blood levels and muscle damage risk
• Warfarin and coumarin anticoagulants — caution: This combination can increase the blood-thinning effect and raise bleeding risk; INR monitoring required
• Digoxin — caution: May raise digoxin levels in the blood; monitoring needed when starting this combination
• Bile acid sequestrants (e.g., cholestyramine) — timing matters: Reduce ezetimibe absorption; take at least 2 hours before or 4 hours after
• High-dose niacin (≥1 g/day), fibrates, colchicine, daptomycin — caution: All increase the risk of muscle damage when combined

This is not a complete list of interactions. Always talk with your doctor or pharmacist before starting, stopping, or changing any medication.

• Do not take if you have active liver disease or persistent unexplained elevations in liver enzymes
• Do not take if you are pregnant, may become pregnant, or are breastfeeding — this medication can cause fetal harm and passes into breast milk
• Women of childbearing age should use effective contraception while taking this medication; stop it immediately if pregnancy occurs
• Tell your doctor if you are 65 or older — older adults are at higher risk of muscle problems (myopathy)
• Tell your doctor if you have kidney disease — doses above a certain level require extra caution and careful monitoring
• Tell your doctor if you have or have had liver disease, or if you drink substantial amounts of alcohol
• Chinese patients may face a higher risk of muscle problems, particularly if also taking high-dose niacin — discuss this with your prescriber
• Tell your doctor about all medications, supplements, and herbal products you take, as many interact with this combination
• Safety in children under 10 years of age has not been established; Vytorin has been studied in children 10 and older with HeFH

There is no specific antidote for an overdose of ezetimibe/simvastatin. If an overdose is suspected, seek immediate medical attention and use supportive care. A small number of overdose cases have been reported with the individual ingredients; most patients recovered without lasting effects, and reported reactions were generally not severe.

Ezetimibe/simvastatin lowers total cholesterol, LDL cholesterol, apolipoprotein B (a protein that carries harmful cholesterol), and triglycerides, while raising HDL ('good') cholesterol. Ezetimibe alone has been shown to reduce intestinal cholesterol absorption by about 54%. Simvastatin accelerates the liver's uptake of LDL from the blood by boosting LDL receptor activity. Ezetimibe did not meaningfully affect levels of fat-soluble vitamins A, D, or E, and did not impair adrenal hormone production.

Ezetimibe is well absorbed after oral dosing and is rapidly converted in the intestine and liver into an active form (ezetimibe-glucuronide); both forms circulate in the blood with a half-life of about 22 hours, meaning the drug stays active in the body for roughly a day. Simvastatin is a prodrug — it is converted to its active acid form after ingestion, and because the liver extracts most of it on the first pass, only a small amount reaches the general circulation. Both drugs are highly bound to blood proteins. Ezetimibe is eliminated mainly in the feces; simvastatin's breakdown products leave via both urine and feces. Older adults tend to have higher blood levels of both drugs compared to younger adults, so extra caution is warranted in that age group.

Store at 68°F to 77°F (20°C to 25°C).