Statins
Risk of myopathy is higher with:
- Advanced age - Small body frame/frailty - Multisystem disease - High doses of statins - Low vitamin D - Concurrent use of fibrates
Assessment of patients on statins
- comprehensive health history - contraindications - side effects - baseline liver enzymes (these should be monitored regularly) - eye exam to assess for cataracts
Most common side effects of statins
- constipation - peptic ulcer
Other side effects of statins
- headache - dizziness - blurred vision - fatigue - insomnia - diarrhea - nausea - myalgia - skin rashes
Other benefits of statins:
- help the body reabsorb cholesterol that has built up in plaques in the artery walls - thereby preventing further blockage of the blood vessels that can lead to heart attacks (MIs)
Bioavailability of Statins
30-90%
Rosuvastatin
Crestor
Pravastatin
Pravachol
Statin Contraindication
- in patients with a known drug allergy - pregnancy - liver disorders - patients with a history of alcohol abuse
What can patients do to enhance the effectiveness of statins?
- initiate or maintain exercise program - stop smoking - consume a diet lower in cholesterol and saturated fats
Serious Adverse Effects of Statins
- myopathy (muscle pain) - rhabdomyolysis
Statins
- reduce LDL cholesterol - inhibit HMG-CoA (enzyme) reductase - controls cholesterol production in the liver
Crestor (rosuvastatin)
- reduces the risk of cardiovascular evens in people with normal LDL levels
What should the patient know about rhabdomyolysis?
- when recognized early, it is usually reversible with the discontinuation of statin - the injury to muscle tissue can cause muscle aches, which can lead to noncompliance with the medication regimen
Key components of patient education (statins).
1. MOA and indications for taking statins 2. Do not take with grapefruit or its juice 3. Patient should report any adverse effects to the nurse 4. The most common side effects are constipation and GI disturbances 5. Patient should report muscle tenderness IMMEDIATELY 6. Antihyperlipidemic therapy is a lifelong commitment 7. It is dangerous to discontinue statin drugs abruptly. Doing so could lead to death from acute MI
Reduction of cholesterol may be seen in how long?
2 weeks
Ischemic Stroke
A type of stroke that occurs when the flow of blood to the brain is blocked. - Statins prescribed to these patients
Lovastatin
Altoprev
Dyspepsia
Another side effect
Why is the dosage of Rosuvastatin decreased in patients of Asian descent?
Because following a typical therapeutic dose, drug levels in this group are observed to be twice that observed in Caucasians.
Where are statins* largely excreted?
Bile *except for Lovastatin, Pitavastatin, Pravastatin, and Simvastatin. 10-20% of the metabolites of these four statins are excreted in the urine.
True or false: Statin drugs can be crushed.
False
True or false: A large portion of each Statin dose enters the blood stream.
False. Only a small portion of each dose enters the systemic circulation.
True or false: Statins should be given with meals.
False: statins may be given without regard for meals
Why should you not take grapefruit with statins?
Grapefruit and its juice inhibit statin metabolism - can lead to increased levels of drug in the body.
Inhibiting the CYP3A4 system would:
Increase statin drug levels.
Fluvastatin
Lescol
Atorvastatin
Lipitor
Pitavastatin
Livalo
Statin first pass metabolism
Liver - majority of drug is removed from the bloodstream
What four statins are excreted in the urine?
Lovastatin Pitavastatin Pravastatin Simvastatin
CYP3A4
Metabolize: Atorvastatin Lovastatin Simvastatin
Atorvastatin (Lipitor)
PO 0.5 hour onset 1-2 hour peak 7-14 hour half-life Unknown duration of action
Simvastatin (Zocor)
PO 3 day onset of action 1.3-2.4 hour peak Unknown half-life Unknown duration of action
Statins are recommended for who?
Patients who are over 40 years old and whose LDL cholesterol is greater than 100 mg/dL.
Liver
Principal site of statin activity
GI Side Effects
Reduced by increasing fluids and fiber in the diet
Why should the nurse have the patient undergo regular laboratory testing of blood levels?
Statins cause in increase in liver enzymes. - Must ensure that liver enzymes remain within the normal range
How long does it take for therapeutic effect and maximum reduction of LDL cholesterol?
TE: 2-4 weeks MR: 4-6 weeks
Rhabdomyolysis
The breakdown of muscle protein accompanied by myoglobinuria - seems to be dose-dependent - more common in patients receiving a statin in combination with cyclorsporine, gemfibrozil, or erythromycin
How do statins work?
The replace the HMG-CoA that exists in the liver, thereby slowing the production of cholesterol.
Myoglobinuria
The urinary elimination of the muscle protein myoglobin. - can lead to acute renal failure and even death
True or false: Daily use of a statin may increase the risk of cataracts?
True
True or false: Treatment with statin drugs is expected to be a lifelong commitment.
True
True or false: agents can induce the CYP3A4 system.
True. - This would lower the drug level of statins. - Agents that inhibit the CYP3A4 will slow statin metabolism.
True or false: Statins should be given at night.
True: when taken in the evening, effectiveness is increased.
Simvastatin
Zocor