Nurses Compass
Drug Guide
Felodipine
Classification
Therapeutic: Antihypertensive
Pharmacological: Calcium channel blocker (dihydropyridine)
FDA Approved Indications
- Hypertension
Mechanism of Action
Felodipine inhibits calcium ion influx across excitable membranes, primarily in vascular smooth muscle, leading to vasodilation and decreased blood pressure.
Dosage and Administration
Adult: Initial dose of 5 mg once daily, may be titrated up to 10 mg once daily based on response.
Pediatric: Not approved for pediatric use.
Geriatric: Start at lower end of dosing range due to increased sensitivity and comorbidities.
Renal Impairment: Use with caution; no specific dosage adjustment provided.
Hepatic Impairment: Use with caution; start at lower dose due to impaired metabolism.
Pharmacokinetics
Absorption: Well absorbed from gastrointestinal tract; extensive first-pass metabolism.
Distribution: Widely distributed; protein binding approximately 99%.
Metabolism: Primarily hepatic via CYP3A4.
Excretion: Biliary and renal pathways; largely excreted as metabolites.
Half Life: About 24 hours, allowing once-daily dosing.
Contraindications
- Hypersensitivity to felodipine or other dihydropyridines.
- Severe aortic stenosis.
Precautions
- Use with caution in patients with hepatic impairment, have heart failure, or unstable angina.
Adverse Reactions - Common
- Headache (Common)
- Dizziness (Common)
- Flushing (Common)
- Peripheral edema (Common)
Adverse Reactions - Serious
- Arrhythmias (Rare)
- Allergic reactions (rash, angioedema) (Rare)
Drug-Drug Interactions
- Intensive CYP3A4 inhibitors (e.g., ketoconazole, azole antifungals) may increase felodipine levels.
- CYP3A4 inducers (e.g., rifampin) may decrease its effectiveness.
Drug-Food Interactions
- Grapefruit juice (may increase plasma levels).
Drug-Herb Interactions
N/ANursing Implications
Assessment: Monitor blood pressure and heart rate regularly during therapy. Assess for signs of hypotension.
Diagnoses:
- Risk for hypotension
- Ineffective tissue perfusion
Implementation: Administer orally, preferably in the morning. Observe for signs of excessive hypotension.
Evaluation: Assess blood pressure and symptom control regularly to determine therapeutic effectiveness.
Patient/Family Teaching
- Take medication exactly as prescribed.
- Avoid grapefruit juice during therapy.
- Report any signs of swelling, dizziness, or chest pain.
- Do not stop medication abruptly.
Special Considerations
Black Box Warnings:
- None currently for felodipine.
Genetic Factors: Genetic variations in CYP3A4 may affect metabolism.
Lab Test Interference: May cause false low readings of serum digoxin.
Overdose Management
Signs/Symptoms: Severe hypotension, tachycardia or bradycardia, dizziness, syncope.
Treatment: Supportive care, intravenous fluids, vasopressors if necessary, and calcium infusion as an antidote in severe cases.
Storage and Handling
Storage: Store at room temperature away from moisture and heat.
Stability: Stable for 2 years when stored properly.