Drug Information

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How does this medication work? What will it do for me?

Simvastatin belongs to the group of medications known as HMG CoA reductase inhibitors ("statins"). It is used in addition to diet and exercise to lower cholesterol levels.

It is also used to decrease the risk of heart attack, stroke, or death regardless of whether cholesterol levels are high or not for people who have coronary heart disease (CHD) or have other arteries in the body that are blocked, or for those who have diabetes and are over the age of 40.  It is also used to treat people who have certain inherited cholesterol disorders.

Simvastatin works by blocking an enzyme that helps create cholesterol in the body. As a result, less cholesterol is made and levels of cholesterol in the blood decrease. Simvastatin lowers the level of total cholesterol and low-density lipoprotein (LDL, or "bad" cholesterol) and raises high-density lipoprotein (HDL, or "good" cholesterol) levels.

The medication usually takes about 2 to 4 weeks to have a significant effect on the cholesterol level in your blood. After this time, your doctor will likely send you for a blood test to check for changes in your cholesterol levels.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

How should I use this medication?

Before or when starting simvastatin, you should be placed on a cholesterol-lowering diet. If appropriate, a health care professional will discuss an individualized program of weight control and physical exercise with you.

When it is being used to reduce cholesterol levels, the usual starting dose of this medication is 10 mg taken by mouth, once a day, in the evening.

For children between the ages of 10 and 17, who have an inherited cholesterol disorder, the usual starting dose is also 10 mg taken by mouth once a day, in the evening.

The usual starting dose of simvastatin to reduce the risk of heart attack or stroke is 40 mg taken by mouth once a day, in the evening.

Your doctor may adjust the dose after a period of time, depending on how well it is working for you or how well you are tolerating the medication. The maximum daily dose for children and adolescents 10 to 17 years of age is 40 mg. For adults, the maximum recommended daily dose is 80 mg, which may be used for some people who have been taking this amount for a long time with no muscle problems or people at high risk of heart disease who have problems taking other "statins." The maximum daily dose may be lower for people taking certain medications.

For best results in lowering your cholesterol, it is very important that you closely follow the diet suggested by your doctor.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

It is important to take this medication exactly as prescribed by your doctor. If you miss a dose, take it as soon as possible and continue with your regular schedule. If it is almost time for your next dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store this medication at room temperature and keep it out of the reach of children.

What form(s) does this medication come in?
Ava-Simvastatin is no longer being manufactured for sale in Canada. For brands that may still be available, search under simvastatin. This article is being kept available for reference purposes only. If you are using this medication, speak with your doctor or pharmacist for information about your treatment options.
Who should NOT take this medication?

Do not take simvastatin if you:

  • are allergic to simvastatin or any ingredients of the medication
  • are breast-feeding
  • are pregnant or plan to become pregnant
  • have active liver disease or unexplained increases in liver function tests
  • are taking certain other medications, such as:
    • "azole" antifungal medications (e.g., fluconazole, ketoconazole)
    • protease inhibitors (e.g., atazanavir, darunavir, ritonavir, saquinavir)
    • macrolide antibiotics (e.g., erythromycin, clarithromycin)
    • medications containing cobicistat
    • gemfibrozil
    • cyclosporine
    • danazol
What side effects are possible with this medication?

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

  • abdominal pain
  • acid reflux or heartburn
  • constipation
  • diarrhea
  • difficulty getting/maintaining an erection
  • dizziness
  • gas
  • hair loss
  • headache
  • itchy skin
  • nausea
  • trouble sleeping
  • upset stomach
  • vomiting
  • weakness

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

  • blurred vision
  • breathing problems (e.g., shortness of breath, persistent cough)
  • confusion
  • memory loss
  • signs of depression (e.g., poor concentration, changes in weight, changes in sleep, decreased interest in activities, thoughts of suicide)
  • symptoms of high blood sugar (e.g., frequent urination, increased thirst, excessive eating, unexplained weight loss, poor wound healing, infections, fruity breath odour)
  • symptoms of liver damage (e.g., yellow skin or eyes, abdominal pain, dark urine, clay-coloured stools, loss of appetite, nausea and vomiting, or itching)
  • symptoms of muscle damage (e.g., unexplained muscle pain, tenderness, or weakness, or brown or discoloured urine – especially if you also have a fever or a general feeling of being unwell)

Stop taking the medication and seek medical attention immediately if any of the following occur:

  • severe skin rash, including skin blistering and peeling (possibly with headache, fever, coughing, or aching before the rash begins)
  • signs of pancreatitis (e.g., abdominal pain on the upper left side, back pain, nausea, fever, chills, rapid heartbeat, swollen abdomen)
  • symptoms of a serious allergic reaction (e.g., swelling of the face or throat, hives, or difficulty breathing)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Are there any other precautions or warnings for this medication?

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Alcohol: Consumption of alcohol can increase the risk of liver damage when taking simvastatin. If you regularly drink more than 3 drinks of alcohol daily, the risk is further increased and you should be closely monitored by your doctor while taking this medication.

Diabetes: Simvastatin, like other medications in this family, may cause a loss of control of blood sugar levels and glucose tolerance may change. People with diabetes may find it necessary to monitor their blood sugar more frequently while using this medication.

If you have diabetes or are at risk for developing diabetes, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Grapefruit juice: Don't drink grapefruit juice while taking this medication, as it can increase the amount of simvastatin in the blood and increase the risk of serious side effects.

Kidney problems: People with decreased kidney function should discuss with their doctor how this medication may affect their medical condition, how their medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Liver function: Liver disease or reduced liver function may cause this medication to build up in the body, causing side effects. If you have a history of liver disease, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Laboratory tests show signs of harmful effects to the liver that may occur for a small percentage of people who take simvastatin. When this medication is stopped, liver function usually slowly returns to normal. Your doctor will perform regular tests to check your liver function.

This medication should not be used by people with active liver disease or by people whose liver function tests are higher than normal.

Muscle effects: In rare cases, serious muscle pain, cramps, and weakness have been associated with the use of statin medications (i.e., cholesterol-lowering medications whose names end in "statin," such as atorvastatin, fluvastatin, lovastatin, pravastatin, rosuvastatin, or simvastatin), especially at higher doses. Before taking this medication, tell your doctor or pharmacist if you:

  • are 65 years of age or older
  • are female
  • are taking other cholesterol-lowering medications such as fibrates (e.g., gemfibrozil, fenofibrate), ezetimibe, or niacin
  • do excessive physical exercise
  • have a family history of muscular disorders
  • have diabetes
  • have had any past problems with the muscles (pain, tenderness) after taking a statin medication
  • have hypothyroidism (low thyroid) that is not controlled with medication
  • have kidney or liver problems
  • have undergone surgery or other tissue injury
  • regularly drink 3 or more alcoholic drinks daily

Report any unexplained muscle pain, tenderness, weakness, or cramps, or any brown or discoloured urine to your doctor immediately, particularly if you are also experiencing malaise (a general feeling of being unwell) or fever.

Pregnancy: Simvastatin should not be taken during pregnancy. It may cause harm to the unborn baby. If you become pregnant, stop taking this medication and contact your doctor immediately.

Breast-feeding: It is not known if simvastatin passes into breast milk. If you are a breast-feeding mother and are taking this medication, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of using this medication have not been established for children less than 10 years of age or in girls who have not started menstruating.

Seniors: If you are 65 years of age or older, you may experience more side effects. Your doctor will monitor you closely while you are taking this medication.

What other drugs could interact with this medication?

There may be an interaction between simvastatin and any of the following:

  • alprazolam
  • amiodarone
  • antacids (e.g., aluminum hydroxide, calcium carbonate, magnesium hydroxide)
  • aprepitant
  • "azole" antifungals (e.g., itraconazole, ketoconazole, posaconazole, voriconazole)
  • bicalutamide
  • bezafibrate 
  • bosentan
  • calcium channel blockers (e.g., amlodipine, diltiazem, nifedipine, verapamil)
  • ceritinib
  • ciprofloxacin
  • cobicistat
  • colchicine
  • conivaptan
  • cyclosporine
  • cyproterone 
  • dabigatran
  • danazol
  • digoxin
  • dronedarone
  • elbasvir
  • eltrombopag
  • enzalutamide
  • eslicarbazepine
  • everolimus
  • fenofibrate
  • gemfibrozil
  • grapefruit juice
  • grazoprevir
  • HIV non-nucleoside reverse transcriptase inhibitors (NNRTIs; e.g., efavirenz, etravirine, nevirapine)
  • HIV protease inhibitors (e.g., atazanavir, indinavir, ritonavir, saquinavir)
  • isoniazid
  • ivacaftor
  • letermovir
  • lomitapide
  • macrolide antibiotics (e.g., azithromycin, clarithromycin, erythromycin)
  • mifepristone 
  • niacin (nicotinic acid)
  • niacinamide
  • phenytoin
  • quinidine
  • raltegravir
  • red yeast rice
  • rifampin
  • rupatadine
  • St. John's wort
  • sildenafil
  • siltuximab
  • sitagliptin
  • spironolactone
  • teriflunomide
  • ticagrelor
  • trabectedin
  • tyrosine kinase inhibitors (e.g., dasatinib, imatinib, nilotinib, sunitinib)
  • voxilaprevir
  • warfarin

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

  • stop taking one of the medications,
  • change one of the medications to another,
  • change how you are taking one or both of the medications, or
  • leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications that you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.

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