21.2 Statins (HMG-CoA Reductase Inhibitors) and PCSK9 Inhibitors

Statins and PCSK9 inhibitors are powerful tools in the fight against high cholesterol. These medications work in different ways to lower lipid levels in the blood, reducing the risk of heart disease and stroke.

Understanding how these drugs work is crucial for nurses. We'll look at their mechanisms of action, clinical uses, side effects, and important nursing considerations to help patients get the most benefit from lipid-lowering therapy.

Mechanisms of Action and Effects

Statins and PCSK9 inhibitors lower lipid levels

• Statins (HMG-CoA reductase inhibitors)
  • Block HMG-CoA reductase enzyme involved in rate-limiting step of liver cholesterol synthesis
  • Decreases liver cholesterol production causing upregulation of LDL receptors on liver cells
  • Increased LDL receptor expression enhances removal of LDL and VLDL from blood (atorvastatin, simvastatin)
• PCSK9 inhibitors
  • Monoclonal antibodies bind to and inhibit PCSK9 protein
  • PCSK9 normally binds LDL receptors causing their breakdown and reducing LDL removal
  • Inhibiting PCSK9 increases available LDL receptors on liver cells
  • Enhanced LDL receptor expression increases removal of LDL and VLDL from blood (evolocumab, alirocumab)

Clinical Use and Efficacy

Indications and effectiveness of statins vs PCSK9 inhibitors

• Indications
  • Statins first-line for primary and secondary prevention of atherosclerotic cardiovascular disease (ASCVD)
  • PCSK9 inhibitors for familial hypercholesterolemia or ASCVD patients needing more LDL lowering despite maximum statin dose
• Effectiveness
  • Statins reduce LDL 30-50% and significantly reduce cardiovascular event and mortality risk
  • PCSK9 inhibitors further lower LDL 50-60% when added to statin
  • Statin plus PCSK9 inhibitor can reduce LDL up to 75-80%
  • PCSK9 inhibitors show additional cardiovascular risk reduction when combined with statins

Adverse Effects and Interactions

Common side effects and drug interactions with statins and PCSK9 inhibitors

• Statins
  • Common side effects: muscle pain/weakness, fatigue, digestive issues, headache, elevated liver enzymes
  • Rare serious side effects: myopathy, rhabdomyolysis, liver damage
  • Drug interactions: increased muscle side effect risk when combined with certain antibiotics, antifungals, fibrates
• PCSK9 inhibitors
  • Generally well-tolerated with few side effects
  • Most common adverse effect is injection site reactions (pain, redness, itching)
  • No significant drug interactions identified so far

Nursing Considerations

Key nursing considerations and patient education for lipid-lowering medications

• Nursing considerations
  • Monitor lipid levels and liver function tests regularly
  • Assess for muscle symptoms and check creatine kinase if muscle symptoms occur
  • Encourage medication adherence and lifestyle changes
  • Educate patients to report any adverse effects
• Patient education
  • Emphasize how lipid-lowering medications reduce cardiovascular risk
  • Discuss importance of taking medications as prescribed and not stopping without consulting provider
  • Encourage heart-healthy lifestyle (low-fat diet, regular exercise, quit smoking)
  • Advise reporting any muscle symptoms, unexplained fatigue, yellowing skin/eyes
  • For PCSK9 inhibitors, teach proper injection technique and medication storage