Overview
This lecture covers calcium channel blockers (CCBs), their classifications, appropriate use in hypertension, drug interactions, management of chronic kidney disease (CKD), and current lipid guidelines for statin therapy.
Calcium Channel Blockers: Classification & Use
- CCBs are divided into DHPs (dihydropyridines, e.g., amlodipine) and non-DHPs (verapamil, diltiazem).
- DHPs lower blood pressure without significantly affecting heart rate ("DHP"—doesn't hurt the pulse).
- Non-DHPs decrease both heart rate and blood pressure.
- DHPs are preferred in older adults or when only blood pressure needs to be lowered.
- Amlodipine standard initial dose: 2.5–5 mg daily; 2.5 mg is a safe initial choice.
Medication Management & Chronopharmacology
- Continue existing antihypertensive meds (e.g., facinopril and HCTZ) when adding amlodipine.
- Chronopharmacology: administering medications at times for maximum effect (e.g., statins and CCBs at night, aspirin at bedtime).
- CCBs work better when taken at night; combine with other meds accordingly unless cognitive issues dictate otherwise.
Chronic Kidney Disease: Key Considerations
- In CKD with decreased GFR (e.g., 50), do not increase HCTZ or ignore the problem.
- Encourage increased oral fluids to support kidney function.
- Stop NSAIDs like naproxen, as they reduce renal prostaglandins and impair renal blood flow.
- Do not add ARBs if already on ACE inhibitors; do not stop amlodipine as CCBs are renal-friendly.
Case Management: Hypertensive Diabetic Patient
- Blood pressure goal for diabetics: <140/<90 mmHg.
- Alternatives to improve control: increase ARB dose, increase amlodipine dose, consider adding metoprolol (beta-blocker) especially post-MI.
- Avoid increasing HCTZ if history of gout; minimal BP benefit and increases gout risk.
- When increasing ARB, monitor BUN, creatinine, potassium, and blood pressure.
- When adding metoprolol, monitor heart rate and blood pressure.
Lipid Management & Guidelines
- New guidelines (2013) divide statin recommendations into four groups.
- Group 1: Prior MI/stroke—high-intensity statin.
- Group 2: LDL ≥190 mg/dL—high-intensity statin.
- Group 3: Diabetes age 40–75, LDL 70–189 mg/dL—moderate-intensity statin.
- Group 4: 10-year CVD risk ≥7.5%—statin recommended.
- Diabetics like Mr. Jones (age 66, LDL 130) should be on moderate-intensity statin therapy.
Key Terms & Definitions
- DHP (Dihydropyridine) — CCB subclass, lowers BP, minimal effect on heart rate.
- Non-DHP — CCB subclass (verapamil, diltiazem), lowers both BP and heart rate.
- Chronopharmacology — Study of how medication timing affects effectiveness.
- GFR (Glomerular Filtration Rate) — Marker of kidney function.
- ARB (Angiotensin Receptor Blocker) — Antihypertensive, retains potassium.
- ACE Inhibitor — Antihypertensive, retains potassium.
- NSAID (Nonsteroidal Anti-inflammatory Drug) — Can impair renal blood flow.
- Metoprolol — Cardio-selective beta blocker, lowers HR and BP.
- Statin — Drug class lowering LDL cholesterol.
Action Items / Next Steps
- Review current antihypertensive regimens and make adjustments according to guidelines.
- Monitor kidney function and electrolytes when modifying ACE/ARB dosing.
- Counsel patients on optimal medication timing (chronopharmacology).
- Assess statin eligibility based on updated guidelines for diabetic and high-risk patients.
- Avoid NSAIDs in patients with reduced renal function.