Generic Name

Isradipine

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Classification

FDA Approved Indications

• Hypertension

Mechanism of Action

Isradipine inhibits calcium ions from entering vascular smooth muscle and cardiac muscle cells through voltage-gated L-type calcium channels, resulting in vasodilation and decreased blood pressure.

Dosage and Administration

Adult: Initial: 5 mg orally twice daily. Dose may be titrated up to 10 mg twice daily based on response.

Pediatric: Not approved for pediatric use.

Geriatric: Start at lower doses; monitor closely due to increased sensitivity.

Renal Impairment: No initial dose adjustment necessary; adjust as needed based on response.

Hepatic Impairment: Use with caution; dose adjustment may be necessary, especially in severe impairment.

Pharmacokinetics

Absorption: Well absorbed orally with peak plasma levels in 1-2 hours.

Distribution: Extensive tissue distribution; protein bound approximately 91%.

Metabolism: Primarily hepatic via CYP3A4.

Excretion: Metabolites excreted mainly in feces, minor renal excretion.

Half Life: Approximately 7-8 hours.

Contraindications

• Hypersensitivity to dihydropyridines or any component of the formulation.
• Concurrent use with strong CYP3A4 inhibitors in some cases.

Precautions

• Use with caution in patients with severe aortic stenosis, heart failure, or hypotension.
• Monitor blood pressure regularly during therapy.

Adverse Reactions - Common

• Dizziness (Common)
• Flushing (Common)
• Headache (Common)
• Peripheral edema (Common)

Adverse Reactions - Serious

• Hypotension (Less common)
• Bradycardia or tachyarrhythmias (Rare)

Drug-Drug Interactions

• CYP3A4 inhibitors (e.g., ketoconazole, clarithromycin) may increase isradipine levels.
• Other antihypertensives may have additive effects.

Drug-Food Interactions

• Grapefruit juice may increase plasma concentrations of isradipine.

Drug-Herb Interactions

N/A

Nursing Implications

Patient/Family Teaching

• Take medication exactly as prescribed.
• Monitor for signs of hypotension (dizziness, fainting).
• Avoid grapefruit juice during therapy.
• Report any swelling, rapid heartbeat, or severe dizziness.

Special Considerations

Black Box Warnings:

• None specifically for isradipine.

Genetic Factors: None established.

Lab Test Interference: None known.

Overdose Management

Signs/Symptoms: Severe hypotension, tachycardia or bradycardia, dizziness, fainting.

Treatment: Supportive care with IV fluids; vasopressors if necessary; activated charcoal if ingestion was recent.

Storage and Handling

Storage: Store at room temperature, away from moisture and heat.

Stability: Stable under recommended storage conditions.