Isosorbide Mononitrate: uses, dosing, side effects & brands
Isosorbide Mononitrate is a nitrate vasodilator sold in the U.S. under 4 brand and generic names, for angina pectoris, coronary disease and cyanosis. Below: what the FDA label says, every product that contains it, what the pills look like, and its recall record.
Key facts
- Drug class
- Nitrate Vasodilator
- Treats (across its forms)
- Angina Pectoris, Coronary Disease and Cyanosis
- Available as
- Tablet, extended release · Tablet
- Sold as
- 4 products — Imdur, Ismo and Isosorbide Mononitrate, and others
- Prescription?
- Prescription only
- Generic available?
- Yes
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How Monoket is dosed
From the FDA label for Monoket (application NDA020215). Other isosorbide mononitrate products — different forms, different strengths — are dosed differently. Follow the label for the one you were prescribed.
The recommended regimen of Isosorbide Mononitrate Tablets is 20 mg twice daily, with the doses seven hours apart. A starting dose of 5 mg (½ tablet of the 10 mg dosing strength) might be appropriate for persons of particularly small stature but should be increased to at least 10 mg by the second or third day of therapy. Dosage adjustments are not necessary for elderly patients or patients with altered hepatic or renal function. As noted above ( Clinical Pharmacology ), multiple studies of organic nitrates have shown that maintenance of continuous 24-hour plasma levels results in refractory tolerance. The asymmetric (2 doses, 7 hours apart) dosing regimen for Isosorbide Mononitrate Tablets provides a daily nitrate-free interval to minimize the development of tolerance. As also noted under Clinical Pharmacology , well-controlled studies have shown that tolerance to Isosorbide Mononitrate Tablets occurs to some extent when using the twice-daily regimen in which the two doses are given seven hours apart. This regimen has been shown to have antianginal efficacy beginning one hour after the first dose and lasting at least seven hours after the second dose. The duration (if any) of antianginal activity beyond fourteen hours has not been studied. In clinical trials, isosorbide mononitrate has been administered in a variety of regimens and doses. Doses above 20 mg twice a day (with the…
Everything below is the FDA label for Monoket (tablet). Isosorbide Mononitrate is also sold as tablet, extended release, and those are different medicines to take — follow the label for the one you were prescribed.
Monoket side effects
To report SUSPECTED ADVERSE REACTIONS, contact Omnivium Pharmaceuticals LLC at 1-888-807-1048 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. Headache is the most frequent side effect and was the cause of 2% of all dropouts from controlled-clinical trials. Headache decreased in incidence after the first few days of therapy. The following table shows the frequency of adverse reactions observed in 1% or more of subjects in 6 placebo-controlled trials, conducted in the United States and abroad. The same table shows the frequency of withdrawal for these adverse reactions. In many cases the adverse reactions were of uncertain relation to drug treatment. Frequency of Adverse Reactions (Discontinuations)* 6 Placebo-Controlled Studies Dose Placebo 5 mg 10 mg 20 mg Patients 160 54 52 159 Headache 6% (0%) 17% (0%) 13% (0%) 35% (5%) Fatigue 2% (0%) 0% (0%) 4% (0%) 1% (0%) Upper Respiratory Infection <1% (0%) 0% (0%) 4% (0%) 1% (0%) Pain <1% (0%) 4% (0%) 0% (0%) <1% (0%) Dizziness 1% (0%) 0% (0%) 0% (0%) 4% (0%) Nausea <1% (0%) 0% (0%) 0% (0%) 3% (2%) Increased Cough <1% (0%) 0% (0%) 2% (0%) <1% (0%) Rash 0% (0%) 2% (2%) 0% (0%) <1% (0%) Abdominal Pain <1% (0%) 0% (0%) 2% (0%) 0% (0%) Allergic Reaction 0% (0%) 0% (0%) 2% (0%) 0% (0%) Cardiovascular Disorder 0% (0%) 2% (0%) 0% (0%) 0% (0%) Chest Pain <1% (0%) 0% (0%) 2% (0%) <1% (0%) Diarrhea 0% (0%) 0% (0%) 2% (0%) 0% (0%) Flushing 0%…
Who shouldn’t take Monoket
Isosorbide mononitrate is contraindicated in patients who are allergic to it. Do not use isosorbide mononitrate in patients who are taking certain drugs for erectile dysfunction (phosphodiesterase inhibitors), such as sildenafil, tadalafil, or vardenafil. Concomitant use can cause severe hypotension, syncope, or myocardial ischemia. Do not use isosorbide mononitrate in patients who are taking the soluble guanylate cyclase stimulator riociguat. Concomitant use can cause hypotension.
Every isosorbide mononitrate product we track (4)
Same active ingredient — different manufacturer, form, price and FDA recall record. That last one is what our independent score measures.
| # | Drug | Rating | Type | Form | Generic? | Pharmacy pays | |
|---|---|---|---|---|---|---|---|
| 1 | Not yet rated | Prescription | Tablet | No data | — | View → | |
| 2 | Not yet rated | Prescription | Tablet | No data | — | View → | |
| 3 | Not yet rated | Prescription | Tablet | No data | — | View → | |
| 4 | Not yet rated | Prescription | Tablet | No data | — | View → |
What isosorbide mononitrate pills look like
Imprint codes, colour and shape from the FDA’s labelling data. Match the imprint on your pill — or search any imprint.
| Imprint | Strength | Colour | Shape | Maker |
|---|---|---|---|---|
| 60;60;1105 | 60 mg | white | oval | — |
| 3;0;1104 | 30 mg | white | oval | — |
| 60;60;1105 | 60 mg | white | oval | — |
| 120;1106 | 120 mg | white | oval | — |
| GL;251 | 20 mg | blue | round | — |
| 3;0;1104 | 30 mg | white | oval | — |
| GL;250 | 10 mg | blue | round | — |
| ANI;252 | 10 mg | white | round | — |
| ANI;253 | 20 mg | yellow | round | — |
| 3;0;1104 | 30 mg | white | oval | — |
Can you crush or split isosorbide mononitrate?
At least one isosorbide mononitrateproduct is labelled to be swallowed whole — crushing an extended-release tablet releases the whole day’s dose at once. Which applies depends on the form you were given.
What each isosorbide mononitrate label says about crushing, splitting and chewingHow long isosorbide mononitrate keeps
No isosorbide mononitrate label we read sets a separate limit for after opening, but they do specify how it must be stored — and the stability behind any date assumes those conditions.
Does isosorbide mononitrate expire? The in-use limits and storage rules from its labelsWhat people report to the FDA about isosorbide mononitrate
The FDA Adverse Event Reporting System (FAERS) collects reports from patients and clinicians. It holds 22,026 reports naming isosorbide mononitrate, and the FDA flagged 84% of those reports as serious. The effects reported most often — leaving out reports about overdose, misuse or the condition being treated, which dominate the raw list for common medicines:
- dyspnoea1,644 reports
- dizziness1,551 reports
- fatigue1,383 reports
- diarrhoea1,381 reports
- nausea1,353 reports
- chest pain1,276 reports
- headache1,137 reports
- myocardial infarction1,109 reports
Read these as a signal, not a rate. A report does not mean isosorbide mononitrate caused the effect — anyone can file one, and many describe people taking several medicines for several conditions. Crucially there is no denominator: FAERS does not record how many people took the drug, so these counts cannot be turned into “X% of patients” — a bigger number often just means a more widely used or more talked-about drug. Duplicates exist, and publicity drives reporting. For what is actually established, read the FDA label section above.
Source: openFDA drug/event (FAERS), retrieved August 25, 2026.
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Frequently asked questions
What is Monoket?
Monoket (Isosorbide Mononitrate) is a nitrate vasodilator used to treat Angina Pectoris, Coronary Disease, Cyanosis, Gastroesophageal Reflux.
What kind of drug is isosorbide mononitrate?
The FDA classifies isosorbide mononitrate as a nitrate vasodilator. Nitrate vasodilators are converted in the body into nitric oxide, which relaxes the smooth muscle in blood vessel walls and widens them. This mainly opens up the veins, reducing how hard the heart must work and relieving chest pain. If you are checking whether it is safe to combine with something else, the class is what matters — two drugs from the same class usually should not be stacked.
Can you take isosorbide mononitrate with other medicines?
It depends on the medicine. We check it against the FDA labels rather than guessing: our interaction checker searches each drug's own label for the other and quotes what it says, naming the section it came from. Run isosorbide mononitrate against whatever else you take — and remember that a label not naming a drug is not the same as that combination being safe.
What brand names is isosorbide mononitrate sold under?
We track 4 isosorbide mononitrate-containing products in the U.S.: Imdur, Ismo, Isosorbide Mononitrate and Monoket. They are the same active ingredient; they differ in form, manufacturer, price and FDA recall record.
What forms does isosorbide mononitrate come in?
Across the brands we track, isosorbide mononitrate is currently marketed as tablet, extended release and tablet, per the FDA's National Drug Code Directory. Each form is dosed differently — follow the label for the exact product you were prescribed.
Is there a generic isosorbide mononitrate?
Yes. Our catalog lists 1 generic isosorbide mononitrate product alongside the brand versions. A generic has the same active ingredient and must meet the FDA's bioequivalence standard; it usually costs less. Ask your pharmacist which one your plan covers.
Cite this page
- APA
- pharmaranks. (2026, July 24). Isosorbide Mononitrate: uses, dosing, side effects & brands. https://pharmaranks.com/drugs/isosorbide-mononitrate
- MLA
- “Isosorbide Mononitrate: uses, dosing, side effects & brands.” pharmaranks, 24 July 2026, https://pharmaranks.com/drugs/isosorbide-mononitrate.
We summarise public FDA and NIH sources — for a clinical claim, cite the primary source we link to as well.
Sources: FDA openFDA drug label, National Drug Code Directory, and Enforcement (recall) database. This page reproduces public FDA data and is not medical advice. Dosing is set by your prescriber.
Read the full FDA label for isosorbide mononitrate on DailyMed (NIH) ↗.