Heart Patients in Portugal Face Medication Shortage Until June—Here's Your Action Plan

Why This Matters

• Shortage through June 30, 2026: The Portuguese National Authority of Medicines (Infarmed) confirmed that manufacturer Viatris Limited cannot replenish Mononitrato de Isossorbido Mylan 60 mg tablets until June 30, 2026.

• Pharmacies operating under strict rations: Each patient may receive only one package per visit, forcing careful inventory management and early conversations with doctors.

• No identical substitute exists: The 60 mg strength has no direct replacement, meaning patients must either dose-adjust or switch medication classes entirely.

• Clinicians must act now: Affected heart patients need medical guidance before supply fully depletes; waiting risks treatment continuity gaps.

The Shortage Timeline and What It Means

Viatris Limited—the generic pharmaceutical giant created from Mylan's 2020 merger with Pfizer's Upjohn division—informed Infarmed that it cannot manufacture or deliver the extended-release 60 mg formulation of isosorbide mononitrate (Mononitrato de Isossorbido) through June 30, 2026. Infarmed has not publicly disclosed the specific reasons for the production halt.

The shortage affects a foundational angina medication. Isosorbide mononitrate is a vasodilator that relaxes blood vessel walls, allowing blood to flow more freely to heart tissue starved during physical exertion or emotional stress. Patients taking the extended-release form once daily benefit from a predictable, steady medication level that prevents chest pain episodes while maintaining a nitrate-free window overnight—typically at least 14 hours—to prevent the body from developing tolerance to the drug's effects.

For cardiac patients in Portugal relying on this specific dosage, Infarmed has issued guidance establishing immediate operational constraints across the healthcare system. The instruction is clear: stretch remaining inventory through June 30 while shepherding affected patients toward viable alternatives. No emergency stockpiling is permitted.

How Pharmacies Are Managing the Shortage

Community pharmacies nationwide have received explicit rationing instructions from Infarmed. The protocol is deliberately designed to prevent artificial scarcity while maintaining equitable access:

Pharmacists must dispense only one package of Mononitrato de Isossorbido Mylan 60 mg per patient visit. Before releasing inventory, staff must consult patient records to verify ongoing therapeutic need and ensure someone isn't hoarding medication. Pharmacies are also prohibited from building reserves on their shelves—large stock accumulations are forbidden, a safeguard that prevents one location from depleting supplies needed across neighboring towns or districts.

This approach mirrors crisis management strategies deployed during previous shortages of essential medications, such as certain diabetes injectables and respiratory antibiotics, when Infarmed coordinated centralized oversight to prevent regional scarcity. The strategy works by making scarcity visible early rather than allowing panic buying to obscure real supply until it's completely gone.

Pharmacists, essentially gatekeepers now, face practical pressure. A patient arriving with a prescription expects immediate fulfillment—it's how the system normally works. Having to check records, verify history, and potentially deny a request (or limit quantity) requires staff to explain rationing logic to anxious individuals. Most community pharmacy teams understand the clinical reasoning, but the retail friction is real.

The Dose-Adjustment Path: 60 mg to 50 mg

For most affected patients, Infarmed's primary recommendation is a straightforward substitution: switch to the 50 mg extended-release formulation. The dose reduction—from 60 mg to 50 mg—represents approximately a 17% decrease in daily nitrate exposure, a margin that Infarmed and the National Pharmacy and Therapeutics Committee deemed clinically tolerable for the majority of cases.

The regulatory guidance states that substitution should not meaningfully impact clinical response, yet advises physicians to implement closer patient monitoring during the transition. This language reflects appropriate caution: while 50 mg maintains therapeutic plasma concentrations (above 100 ng/mL for roughly 17 hours post-dose) within established efficacy windows, individual patient variability in drug metabolism means some people may experience slightly diminished symptom control.

Clinically, the 50 mg dosage remains well within the therapeutic range. Study data indicates that extended-release 50 mg mononitrate delivers stable vasodilation sufficient to prevent daytime angina episodes in the majority of stable angina patients. The critical factor—preserving the overnight nitrate-free window to avoid tolerance—remains unchanged whether patients take 60 mg or 50 mg once daily.

However, substitution is not one-size-fits-all. Patients already struggling with angina control on 60 mg may experience worsening symptoms at 50 mg. Conversely, some patients tolerated 60 mg despite mild side effects like headache, dizziness, or blood pressure drops; the lower dose might actually improve tolerability. Physicians must reassess each patient individually, examining symptom frequency, exercise tolerance, and quality-of-life metrics before and after dose reduction.

Alternative Medications for Stable Angina

For patients where the 50 mg switch proves inadequate or clinically contraindicated, Infarmed outlines a tiered framework of alternative therapies. These medications work through different mechanisms, offering cardiologists flexibility in treatment design.

Beta-blockers remain the cornerstone first-line treatment for stable angina in Portugal's cardiology protocols. Drugs like metoprolol, atenolol, and bisoprolol slow heart rate and reduce myocardial oxygen demand—addressing the root cause of angina rather than simply dilating blood vessels. They're effective, well-tolerated in most patients, and inexpensive. Their drawback: side effects like fatigue, bradycardia, or sexual dysfunction eliminate them as options for a substantial minority.

Calcium channel blockers—amlodipine, diltiazem, verapamil—serve as verified alternatives when beta-blockers cause intolerable effects or are medically contraindicated (e.g., patients with asthma or severe kidney disease). These medications relax vascular smooth muscle and slow conduction through the heart's electrical system, reducing workload and expanding blood vessel capacity. Some patients tolerate them better than beta-blockers; others develop ankle swelling or constipation.

For patients exhausting traditional options, Infarmed's guidance acknowledges emerging alternatives like nicorandil and ivabradina. Nicorandil opens ATP-sensitive potassium channels in vessel walls, a mechanism distinct from nitrates and older agents. Ivabradina selectively slows heart rate without affecting contractility or blood pressure—a useful option for patients requiring additional rate control beyond what beta-blockers alone provide.

Short-acting nitroglycerin—sublingual tablets or spray—remains non-negotiable regardless of long-acting nitrate availability. Patients experiencing acute angina attacks require rapid relief, and sublingual nitroglycerin delivers symptom improvement within 5–10 minutes. Patients should always carry it.

Secondary Prevention: The Larger Picture

Symptom relief is only half the angina treatment equation. Infarmed emphasizes secondary prevention measures that address underlying cardiovascular risk, slowing disease progression and reducing heart attack risk:

Low-dose aspirin (75–150 mg daily) remains standard unless contraindicated by bleeding risk or intolerance. Statins control low-density lipoprotein (LDL) cholesterol, addressing a primary atherosclerosis driver. ACE inhibitors are indicated for patients with hypertension, diabetes mellitus, reduced ejection fraction (≤40%), or chronic kidney disease—drug classes that reduce cardiovascular remodeling and mortality.

These medications work synergistically. A patient transitioning from 60 mg to 50 mg isosorbide mononitrate might simultaneously benefit from statin dose optimization or addition of an ACE inhibitor if not already prescribed. The medication adjustment becomes an opportunity for comprehensive risk assessment.

What Patients Should Do Immediately

If you take Mononitrato de Isossorbido Mylan 60 mg, avoid the temptation to stockpile or suddenly discontinue. Abrupt nitrate withdrawal triggers rebound angina—chest pain can actually worsen in the days following cessation. Instead:

Schedule an appointment with your prescribing cardiologist or general practitioner soon, not after your current supply runs out. Discuss whether 50 mg substitution is appropriate for your condition or whether an alternative therapy makes clinical sense. Your doctor will assess symptom control, exercise tolerance, and overall cardiovascular status.

Inform your pharmacist during your next refill that you're affected by the shortage. Pharmacy staff can flag your profile for priority access to remaining 50 mg inventory if that's your agreed-upon plan, or they can note your switch to alternative medication to avoid confusion during future visits.

Monitor yourself carefully during any dose adjustment or medication change. If chest pain frequency or intensity increases noticeably, contact your doctor immediately rather than waiting weeks for a follow-up appointment. Documentation of how you respond helps your physician fine-tune the regimen.

Keep short-acting nitroglycerin accessible—in your pocket, car, or bedside. Don't rely solely on preventive medications for acute relief.

Managing Supply Disruptions in Essential Medications

Generic medications like isosorbide mononitrate are critical to Portugal's healthcare system, enabling affordable treatment for millions of patients. When production disruptions occur at a single manufacturer, they can affect access nationwide. Infarmed's coordinated response—rationing guidance, pharmacist oversight, and patient transition protocols—represents standard practice for managing such disruptions.

The National Pharmacy and Therapeutics Committee continues to monitor the situation and is reviewing protocols to address pharmaceutical supply chain vulnerabilities. Portugal's cardiology community emphasizes that this shortage, while logistically disruptive, does not represent a therapeutic dead-end. The abundance of alternative medications means virtually all patients can be transitioned safely with appropriate medical guidance.

Looking Forward Through June 30

For now, the priority is methodical patient transition rather than crisis improvisation. The real work happens in consultation rooms and community pharmacy counters over the coming months—conversations between doctors and patients, clear communication from pharmacists, and patient compliance with adjusted regimens. It's unglamorous healthcare management, but it's how supply disruptions are managed without harming the people who depend on these medications daily.