What is the recommended dosage and treatment approach for Felodipine (calcium channel blocker) in managing hypertension and angina?

Felodipine Dosage and Treatment Approach for Hypertension and Angina

For hypertension management, felodipine should be initiated at 2.5-5 mg once daily and can be titrated up to 10 mg once daily as needed, while for angina, the recommended dosage is 5-10 mg once daily. 1, 2, 3

Dosage Recommendations

For Hypertension:

• Initial dose: 2.5-5 mg once daily
• Maintenance dose: 2.5-10 mg once daily
• Maximum dose: 10 mg once daily

For Angina:

• Initial dose: 5 mg once daily
• Maintenance dose: 5-10 mg once daily
• Maximum dose: 10 mg once daily

Special Populations:

• Patients with impaired liver function: Start with 2.5 mg once daily and monitor blood pressure closely during dose adjustments 3
• Elderly patients: Consider starting at lower doses (2.5 mg) due to increased risk of peripheral edema 3

Clinical Efficacy

Felodipine is a dihydropyridine calcium channel blocker that works by:

• Selectively dilating arteriolar resistance vessels
• Reducing peripheral vascular resistance
• Not affecting venous smooth muscle (avoiding orthostatic hypotension)
• Providing natriuretic/diuretic effects that counteract salt and water retention 4

For hypertension, felodipine has been shown to be:

• Effective as monotherapy or in combination with other antihypertensives
• Particularly effective when combined with beta-blockers 4, 5
• Dose-related in its antihypertensive effect 4

For angina, felodipine:

• Provides 24-hour antiischemic protection with once-daily dosing
• Is particularly effective for vasospastic (Prinzmetal's) angina 6
• Can be used as an alternative when beta-blockers are contraindicated or not tolerated 1, 2

Treatment Algorithm

For Hypertension:

1. Initial therapy:

   • Start with 2.5-5 mg once daily
   • For elderly patients or those with hepatic impairment: start with 2.5 mg once daily

2. Dose titration:

   • Evaluate response after 2-4 weeks
   • If blood pressure goal not achieved, increase to 5-10 mg once daily
   • Maximum recommended dose: 10 mg once daily

3. Combination therapy if needed:

   • Felodipine works well with beta-blockers
   • Can be combined with ACE inhibitors, ARBs, or diuretics if monotherapy is insufficient

For Angina:

1. Initial therapy:

   • Start with 5 mg once daily
   • For vasospastic (Prinzmetal's) angina: 10 mg once daily may be more effective

2. Dose titration:

   • Evaluate symptom control after 1-2 weeks
   • If angina persists, increase to 10 mg once daily

3. Combination therapy if needed:

   • For chronic stable angina: can be combined with beta-blockers (preferred)
   • For vasospastic angina: can be used as monotherapy or with long-acting nitrates

Important Precautions and Monitoring

Potential Side Effects:

• Common: peripheral edema (dose and age-dependent, 10-30%), headache, dizziness, flushing 3
• Less common: palpitations, nausea, constipation, warm sensation 3

Contraindications:

• Severe left ventricular dysfunction
• Heart failure with reduced ejection fraction (HFrEF)
• Advanced aortic stenosis 2

Drug Interactions:

• CYP3A4 inhibitors (ketoconazole, itraconazole, erythromycin, grapefruit juice) can significantly increase felodipine levels 3
• When combined with beta-blockers, monitor for excessive bradycardia 2
• May increase metoprolol levels by approximately 31-38% 3

Monitoring:

• Blood pressure response
• Heart rate
• Signs of peripheral edema (especially in elderly patients)
• Liver function in patients with hepatic impairment

Clinical Pearls

• Felodipine's once-daily dosing improves patient compliance compared to medications requiring multiple daily doses
• The peripheral edema associated with felodipine is not due to fluid retention but rather to arteriolar dilation
• Immediate-release nifedipine should not be used for angina without concomitant beta-blockade, but felodipine does not carry this specific warning 1
• Felodipine is often effective in patients with previously "refractory" hypertension 4
• Felodipine has minimal effects on cardiac contractility due to its vascular selectivity, making it safer in patients with borderline cardiac function 4

By following these dosage recommendations and treatment approaches, felodipine can be effectively and safely used to manage both hypertension and angina.