What Is Isradipine? Uses, Dosage, and What You Need to Know in 2026

Isradipine is a prescription medication used to treat high blood pressure (hypertension). It belongs to a class of drugs called calcium channel blockers — specifically the dihydropyridine (DHP) subclass — which work by relaxing the blood vessels to reduce blood pressure. Here's everything you need to know about isradipine in 2026.

Brand Names and Generic Availability

Isradipine was originally marketed under the brand names DynaCirc (immediate-release capsules) and DynaCirc CR (controlled-release tablets). Both brand versions have been permanently discontinued. As of 2026, only generic isradipine capsules manufactured by Teva Pharmaceuticals are available in the United States, in 2.5 mg and 5 mg strengths.

What Is Isradipine Used For?

Isradipine is FDA-approved for treating hypertension. It may be used alone or in combination with other antihypertensive medications, most commonly with a thiazide-type diuretic. High blood pressure, when left untreated, increases the risk of stroke, heart attack, kidney failure, and other serious conditions.

Isradipine also has a well-documented off-label use in pediatric hypertension — particularly for managing acute, severe blood pressure elevations in hospitalized children and adolescents, where it has shown effective and predictable BP reduction.

How Is Isradipine Taken?

Isradipine comes as an oral capsule and is typically taken twice daily (BID) — in the morning and evening. It can be taken with or without food. Take it at the same times each day to maintain consistent blood levels.

Important: Do not stop taking isradipine without talking to your doctor, even if you feel well. High blood pressure usually has no symptoms, and stopping the medication can allow your blood pressure to climb back to dangerous levels.

What Is the Typical Dosage?

• Starting dose: 2.5 mg twice daily (5 mg/day total)
• Typical maintenance dose: 5 mg twice daily (10 mg/day total)
• Maximum dose: 10 mg twice daily (20 mg/day) — though most patients see adequate response at 10 mg/day, and side effects increase above this dose
• Dose titration: Doses may be increased in 5 mg/day increments at 2-4 week intervals based on blood pressure response
• Onset: Blood pressure begins to respond within 2-3 hours; full effect may take 2-4 weeks

Special Dosing Considerations

• Elderly patients: Drug levels are higher in older adults. Start at 2.5 mg BID and titrate carefully.
• Liver impairment: Isradipine is metabolized in the liver. Dose reduction may be needed.
• Pediatric use: Off-label; typical dose is 0.05-0.1 mg/kg per dose for acute hypertension management under specialist guidance.

Is Isradipine a Controlled Substance?

No. Isradipine is not a controlled substance and is not scheduled by the DEA. It is a prescription-only medication, meaning you need a valid prescription from a licensed provider to fill it, but there are no special prescribing restrictions like those for controlled substances.

What Conditions Is Isradipine NOT Used For?

Unlike some other calcium channel blockers (e.g., amlodipine, diltiazem), isradipine does not have an approved indication for angina or heart rate control. It is specifically a vasodilatory antihypertensive. Patients with both hypertension and angina may be better served by amlodipine or a rate-limiting CCB like diltiazem or verapamil.

How to Stay on Your Medication

Because isradipine can be hard to find at pharmacies (see our isradipine shortage update), plan your refills early and confirm availability before pickup. medfinder can contact pharmacies near you to find where isradipine is currently in stock.

The Bottom Line

Isradipine is a proven, effective blood pressure medication. It is taken twice daily as a capsule, is not a controlled substance, and is available as a generic from Teva. While it is not as widely stocked as medications like amlodipine, it remains a valuable option for patients who do well on it and may not tolerate alternatives.