Comprehensive medication guide to Isosorbide including estimated pricing, availability information, side effects, and how to find it in stock at your local pharmacy.
Estimated Insurance Pricing
$0–$25 copay for generic on most commercial plans and Medicare Part D; typically Tier 1–2 on most formularies. Medicare Extra Help can reduce cost to $0–$11/month for qualifying patients.
Estimated Cash Pricing
$20–$270 retail for generic tablets; as low as $7.44–$28 with GoodRx or SingleCare coupons for a 30-day supply of ER tablets.
Medfinder Findability Score
55/100
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Isosorbide is a nitrate medication used to prevent chest pain (angina) caused by coronary artery disease. It comes in two main forms: isosorbide mononitrate (ISMN) and isosorbide dinitrate (ISDN). Isosorbide mononitrate is the more commonly prescribed form and is the active metabolite of isosorbide dinitrate.
Brand names for isosorbide mononitrate included Imdur (extended-release), Monoket, and ISMO — all of which have been discontinued. Only generic isosorbide mononitrate is available in 2026. Isosorbide dinitrate brand names include Isordil and Dilatrate-SR, with generics also available.
A fixed-dose combination of isosorbide dinitrate 20 mg and hydralazine 37.5 mg (brand name BiDil) is FDA-approved for heart failure treatment in African American patients and remains available.
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Isosorbide belongs to the nitrate drug class and works by releasing nitric oxide (NO) in the body. Nitric oxide activates an enzyme called guanylate cyclase, which increases levels of cyclic GMP (cGMP) inside blood vessel smooth muscle cells. This causes the muscle cells to relax, resulting in vasodilation — widening of blood vessels throughout the body.
Vasodilation reduces the work the heart must do in two important ways: venodilation reduces preload (less blood returns to the heart), and arteriolar dilation reduces afterload (less resistance for the heart to pump against). The drug also dilates the coronary arteries directly, increasing blood and oxygen delivery to the heart muscle.
To prevent nitrate tolerance — a phenomenon where continuous exposure reduces effectiveness — isosorbide must be taken with a daily nitrate-free interval of at least 8–12 hours. This is why immediate-release tablets are dosed 7 hours apart (not evenly spaced throughout the day), and extended-release tablets are taken once in the morning.
10 mg — tablet
Immediate-release; typically taken twice daily 7 hours apart
20 mg — tablet
Immediate-release; standard dose taken twice daily 7 hours apart
30 mg — extended-release tablet
Once-daily ER starting dose; swallow whole
60 mg — extended-release tablet
Common once-daily ER maintenance dose; swallow whole
120 mg — extended-release tablet
Maximum once-daily ER dose; swallow whole
5–40 mg — isosorbide dinitrate tablet
Isosorbide dinitrate immediate-release, taken 2–3 times daily with nitrate-free interval
40 mg — isosorbide dinitrate ER capsule
Dilatrate-SR; taken twice daily at least 18 hours apart; max 160 mg/day
Isosorbide mononitrate has experienced intermittent localized shortages in 2026, particularly affecting the 10 mg and 20 mg immediate-release tablets. All brand-name versions have been discontinued, leaving the market dependent on generic manufacturers — a situation that makes supply more fragile when any manufacturer faces production disruptions.
Availability varies significantly by region and pharmacy. Extended-release formulations (30, 60, 120 mg) often have better availability than immediate-release tablets. In April 2026, ANI Pharmaceuticals received FDA approval and launched new isosorbide mononitrate 10 mg and 20 mg tablets, adding new supply to the market.
If your pharmacy is out of isosorbide, medfinder can call pharmacies near you to identify which ones have your specific formulation in stock. Results are texted to your phone so you don't have to spend hours on hold.
Isosorbide mononitrate and isosorbide dinitrate are not controlled substances, meaning any licensed prescriber can write a prescription. There are no DEA registration requirements or special authorization processes needed to prescribe isosorbide.
Providers who commonly prescribe isosorbide include:
For established patients needing refills, telehealth platforms (Teladoc, MDLive, or health system telehealth) can prescribe isosorbide in most states without an in-person visit. New patients with chest pain symptoms should have an in-person evaluation before starting isosorbide.
No. Isosorbide mononitrate and isosorbide dinitrate are not controlled substances and have no DEA schedule. They have no abuse potential or dependence risk. Prescriptions can be written with refills, filled at any licensed pharmacy, and transferred between pharmacies without any special restrictions or limitations.
Because isosorbide is not controlled, it can also be prescribed via telehealth in all states, making it accessible for established patients who need refills and cannot easily make it to an office visit.
Most side effects of isosorbide are related to its vasodilating (blood vessel widening) mechanism. Common side effects include:
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Nitroglycerin
Fastest-acting nitrate; sublingual form for acute angina; patches/ER forms for prevention. Different supply chain than oral isosorbide.
Metoprolol Succinate (Toprol-XL)
First-line beta-blocker for stable angina per ACC/AHA guidelines. Reduces heart rate and workload. Widely available generic.
Amlodipine (Norvasc)
Calcium channel blocker used alone or with isosorbide for angina. Once-daily, well-tolerated, very affordable generic.
Ranolazine (Ranexa)
Second-line antianginal with unique mechanism (late sodium current inhibitor). Doesn't lower BP significantly. Good add-on option when other agents insufficient.
Prefer Isosorbide? We can find it.
Sildenafil (Viagra)
majorAbsolutely contraindicated. Causes potentially fatal synergistic hypotension via combined nitric oxide / cGMP pathway activity.
Tadalafil (Cialis)
majorAbsolutely contraindicated. Same mechanism as sildenafil. Patients must wait 48 hours after last tadalafil dose before taking any nitrate.
Vardenafil (Levitra)
majorAbsolutely contraindicated. Same PDE5 inhibitor class — potentially fatal hypotension with nitrates.
Riociguat (Adempas)
majorAbsolutely contraindicated. sGC stimulator combined with nitrates causes dangerous hypotension.
Alcohol
majorAdditive vasodilation, enhanced dizziness and risk of hypotension. Avoid heavy drinking; discuss safe limits with physician.
Amlodipine (Norvasc)
moderateAdditive hypotension. Combination is used clinically but may require dose adjustments. Rise slowly from sitting/lying positions.
Lisinopril / ACE inhibitors
moderateAdditive blood pressure lowering. Combination is generally tolerated with monitoring.
Metoprolol / Beta-blockers
moderateAdditive BP lowering; however, beta-blockers reduce reflex tachycardia from isosorbide. Combination is common and beneficial.
Tamsulosin (Flomax) / Alpha-blockers
moderateAdditive hypotension, especially orthostatic. Monitor closely in elderly patients.
Ergotamine / Dihydroergotamine
moderateErgot alkaloids may counteract isosorbide's antianginal effect and promote coronary vasoconstriction. Avoid combination.
Isosorbide mononitrate and isosorbide dinitrate are effective, well-established medications for angina prevention with decades of clinical use behind them. They are affordable generics with low-cost options available through discount programs like GoodRx and SingleCare. For most patients, a 30-day supply can cost well under $15 with the right coupon.
The main challenge in 2026 is availability — localized shortages and uneven pharmacy inventory mean some patients struggle to fill their prescriptions even when they can afford them. The most important things to remember: never stop isosorbide abruptly without medical guidance, refill early (with 7–10 days left), and explore mail-order pharmacy for long-term reliability.
If your pharmacy is out of isosorbide, medfinder can help. Enter your medication, dose, and location, and medfinder will call pharmacies near you to find which ones have your isosorbide in stock — texting you the results so you can skip the hold music.
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Our medication guides are researched and written to help patients make informed decisions. All content is reviewed for accuracy and updated regularly. Learn more about our standards
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