Isosorbide Shortage Update: What Patients Need to Know in 2026

If you take isosorbide mononitrate or isosorbide dinitrate for angina prevention, you may have noticed your pharmacy having trouble filling your prescription in 2026. Availability issues with these long-standing heart medications have been affecting patients across the country. This article provides the latest patient-focused update on the isosorbide shortage situation.

What Is the Current Isosorbide Shortage Status in 2026?

Isosorbide mononitrate has experienced documented supply disruptions. The FDA tracks official drug shortages, and Drugs.com maintains an active shortage notice for isosorbide mononitrate tablets. The shortage primarily affects certain strengths — particularly the 10 mg and 20 mg immediate-release tablets — and availability varies significantly by region and pharmacy.

Positive development: In April 2026, ANI Pharmaceuticals received FDA approval and launched new isosorbide mononitrate 10 mg and 20 mg tablets, adding a new generic manufacturer to the market. This should improve overall supply over time, though distribution to individual pharmacies takes weeks to months.

Why Is Isosorbide in Short Supply?

Several factors converged to create the current situation:

• All brand-name versions discontinued. Imdur, Monoket, and ISMO brand-name tablets are no longer manufactured. The entire market relies on generic manufacturers, which means fewer production facilities and more fragile supply chains.
• API sourcing challenges. The active pharmaceutical ingredient in isosorbide is sourced from a limited number of global suppliers. Disruptions in the supply chain — from shipping delays to regulatory manufacturing issues — can affect multiple generic makers simultaneously.
• Manufacturer market exits. Generic drug economics can drive manufacturers out of low-margin markets, leaving fewer suppliers. When one manufacturer exits or reduces production, others may not have capacity to immediately fill the gap.
• Large, steady patient population. Millions of Americans with coronary artery disease depend on isosorbide every day. Even a small reduction in supply creates visible gaps at the patient level.

How This Shortage Affects You as a Patient

The most direct impact is prescription refill delays. Patients who rely on isosorbide to prevent daily angina attacks cannot safely skip doses. Running out — even briefly — can trigger breakthrough chest pain or, in severe cases, more dangerous cardiac events.

Secondary impacts include:

• Time and stress spent calling multiple pharmacies
• Potentially higher prices if switching to a less competitive generic
• Anxiety about medication stability and long-term access

What You Should Do Right Now

Here are the most important steps patients should take during the current shortage:

1. Don't wait until you're out. Refill your isosorbide prescription with 7–10 days of medication remaining. Most insurance plans allow refills at the 75–80% mark.
2. Talk to your pharmacist. Ask when the next shipment is expected and whether they can flag your file for priority. Ask them to search nearby sister locations or affiliated pharmacies.
3. Use a search service. medfinder calls pharmacies in your area to identify which ones can fill your specific isosorbide formulation. This saves hours of calling and getting transferred.
4. Contact your prescriber. Let your doctor know you're having trouble filling your prescription. They may be able to write for a different formulation or strength that's more available, or prescribe a short-term bridge medication.
5. Consider mail-order pharmacy. Mail-order pharmacies often have different supply agreements and may have stock when retail pharmacies don't. 90-day supplies also reduce the frequency of refill disruptions.

Will the Isosorbide Shortage Get Better?

The addition of new manufacturers — like ANI Pharmaceuticals in April 2026 — is a positive signal. More competition in the generic market generally improves supply reliability and keeps prices competitive. However, supply chain normalization takes time. In the near term, patients should plan for continued intermittent availability issues and use proactive strategies to stay supplied.

Key Resources for Patients

Use medfinder to locate pharmacies with isosorbide in stock near you. If you need to consider alternatives, read our guide on alternatives to isosorbide for a detailed breakdown of options to discuss with your doctor.