Prescription medication · Nitrate Vasodilator
isosorbide mononitrate
Also sold as Imdur. This medicine is used to prevent angina, a type of chest pain.
Data updated 2026-05-15
- 19,947
- FDA reportsModerately reported
- $0.23
- Generic price (NADAC)
isosorbide mononitrate (Imdur) is a prescription Nitrate Vasodilator. This medicine is used to prevent angina, a type of chest pain.
Isosorbide mononitrate is a medicine that helps prevent chest pain. It relaxes your blood vessels, so your heart doesn't have to work as hard.
Verify with FDA → · CMS NADAC pricing →
Drug Pricing (NADAC)
Generic Price
$0.23/unit
Generic Available
Yes (10 manufacturers)
Pricing data from NADAC (CMS), effective December 18, 2024. Compare all drug costs →
What it does
This medicine is used to prevent angina, a type of chest pain.
Common side effects
Headache, Dizziness
Key warnings
You should not take this medicine if you are allergic to nitrates or nitrites.
The sections below are summarized in plain English from isosorbide mononitrate's FDA-approved prescribing information. They describe what the official label says, and are not personal medical advice.
How It Works
Isosorbide mononitrate is a nitrate. It works by relaxing the muscles in your blood vessels. This allows more blood and oxygen to flow to your heart while reducing its workload.
How to Take It
Take this medicine once a day in the morning after you wake up. You can take it with or without food. Swallow the tablet whole with a half-glass of water. Do not chew or crush the tablet.
This is a plain-language summary of isosorbide mononitrate's FDA labeling, not individualized dosing advice. Ask a pharmacist or prescriber before changing how you take this medication.
Pregnancy & Breastfeeding
It is not known if this medicine will harm an unborn baby. Talk to your doctor if you are pregnant or plan to become pregnant. It is also not known if this medicine passes into breast milk. Talk to your doctor if you are breastfeeding.
This is a plain-language summary of isosorbide mononitrate's FDA labeling, not individualized advice. Ask a pharmacist or prescriber about pregnancy or breastfeeding on this medication.
Missed Dose
If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and take your next dose at the regular time.
This is a plain-language summary of isosorbide mononitrate's FDA labeling, not individualized advice. Ask a pharmacist or prescriber what to do about your specific missed dose.
Storage
Store at room temperature between 68° and 77°F.
Side Effects (from patient reports)
Based on 19,947 FDA adverse event reports.
Most-reported reactions
Adverse reactions in FAERS for isosorbide mononitrate, by number of reports
- Shortness of breath
Shortness of breath
1,503 reports
- Feeling lightheaded or unsteady
Feeling lightheaded or unsteady
1,397 reports
- Loose or watery stools
Loose or watery stools
1,249 reports
- Feeling tired or weak
Feeling tired or weak
1,242 reports
- Feeling sick to your stomach
Feeling sick to your stomach
1,231 reports
- Pain in the chest
Pain in the chest
1,185 reports
- Heart attack
Heart attack
1,018 reports
- Pain in the head
Pain in the head
999 reports
- Throwing up
Throwing up
942 reports
- Low blood pressure
Low blood pressure
901 reports
What this shows Bars show how often each reaction was reported, not how likely it is to happen, a report records a temporal association, never proof that the drug caused it.
Reports over time
Adverse-event reports filed for isosorbide mononitrate each year to the FDA Adverse Event Reporting System (FAERS).
Year-to-year volume tracks usage, prescribing, and scrutiny, not a change in per-patient risk. Source: FDA FAERS.
Where isosorbide mononitrate sits
isosorbide mononitrate has more FDA adverse-event reports than 55% of the drugs FAERS tracks. A high position reflects how widely a drug is used and watched, not how dangerous it is.
Percentile across all drugs PlainMeds tracks by FAERS report volume. The dot is isosorbide mononitrate; the line is the median (50th percentile).
FDA Adverse Event Report Analysis
Detailed analysis of 19,947 reports from the FDA Adverse Event Reporting System (FAERS). Reports span 2002–2025.
Total Reports
19,947
Reports Mentioning Death
2,526
12.7% of reports — not proof of cause
Hospitalization Reports
9,610
Top Indication
Product Used For Unknown Indication
Gender Distribution
Age Distribution
Most Reported Adverse Reactions (FAERS)
| # | Reaction | Reports |
|---|---|---|
| 1 | DYSPNOEA | 1,503 |
| 2 | DIZZINESS | 1,397 |
| 3 | DIARRHOEA | 1,249 |
| 4 | FATIGUE | 1,243 |
| 5 | NAUSEA | 1,231 |
| 6 | CHEST PAIN | 1,185 |
| 7 | MYOCARDIAL INFARCTION | 1,019 |
| 8 | HEADACHE | 1,000 |
| 9 | VOMITING | 943 |
| 10 | HYPOTENSION | 901 |
| 11 | MALAISE | 899 |
| 12 | ACUTE KIDNEY INJURY | 891 |
| 14 | PAIN | 843 |
| 15 | FALL | 821 |
| 16 | ARTHRALGIA | 752 |
Reactions in Death Reports
Reactions in Hospitalization Reports
Source: FDA FAERS (Adverse Event Reporting System) FDA FAERS (Adverse Event Reporting System) Reports are voluntary and do not establish causation
Serious Warnings
You should not take this medicine if you are allergic to nitrates or nitrites.
Common Questions
Can I use this medicine to treat chest pain that I am currently having?
What should I do if I get a headache from this medicine?
Can I cut or crush the tablet?
How long does it take for this medicine to start working?
Can I drink alcohol while taking this medicine?
What strengths does this medication come in?
What should I tell my doctor before starting this medication?
Can I stop taking this medication suddenly?
Does this medication interact with other medications?
What do the tablets look like?
What are the common side effects of isosorbide mononitrate?
What drug class is isosorbide mononitrate?
Is isosorbide mononitrate safe during pregnancy?
Related Medications in Nitrate Vasodilator
Other drugs grouped near isosorbide mononitrate - same-class peers and common alternatives.
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amiodarone
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atropine
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bumetanide
Bumex
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carvedilol
Coreg
Carvedilol is a medicine that lowers blood pressure and helps your heart work better.
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What the FDA Data Shows for isosorbide mononitrate
The FDA label for isosorbide mononitrate (sold under brand names such as Imdur) classifies it as a prescription-only medication in the Nitrate Vasodilator class. This medicine is used to prevent angina, a type of chest pain. Official labeling lists 2 commonly reported side effects, including Headache, Dizziness.
Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. For this drug, FAERS contains 19,947 voluntary reports. Interaction data is drawn directly from FDA-approved prescribing information. NADAC pricing from CMS shows a generic unit cost of $0.23.
Report counts do not establish causation, a FAERS entry documents a temporal association, not proof that the drug produced the outcome. Widely prescribed medications naturally accumulate more reports than niche therapies, so raw totals must be interpreted alongside total exposure. Shortage status, recall history, and patent information further shape supply and switching decisions. This page summarizes public FDA data for educational purposes only and is not a substitute for professional medical advice, always consult a licensed healthcare provider before starting, stopping, or changing any medication.
Data Sources
Drug labeling: FDA Drug Labels (SPL/DailyMed). Adverse events: FDA Adverse Event Reporting System (FAERS). Pricing: CMS National Average Drug Acquisition Cost (NADAC).
FAERS reports are voluntary and do not establish causation. Drug interactions are derived from FDA labeling and clinical references. Always consult a healthcare professional before making medication decisions.
Last updated: October 23, 2024
Read our methodology - how this data is sourced, computed, and verified.
Data currency: FDA FAERS adverse-event reports through 2025, CMS NADAC acquisition-cost pricing effective December 2024, compiled and last refreshed May 2026. See our methodology for per-source dates and refresh cadence. Spot a figure that looks wrong? Report a correction.
All federal data sources used on this page
- FDA Orange Book - approved drug products with therapeutic equivalence. accessdata.fda.gov/cder/ob
- FDA DailyMed - NIH-hosted drug labeling for FDA-approved meds. dailymed.nlm.nih.gov
- FDA Adverse Event Reporting System (FAERS) - post-marketing safety surveillance. fda.gov/drugs/faers
- NLM RxNorm - standardized clinical drug nomenclature. nlm.nih.gov/research/umls/rxnorm
- CMS Medicare Part B Drug Average Sales Price Files - federal drug pricing data. cms.gov/medicare/part-b-drugs/asp
- FDA Drug Shortages Database - current and resolved drug shortage tracking. accessdata.fda.gov/drugshortages