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Last reviewed on RxList: 11/28/2017
Monoket Side Effects Center

Medical Editor: John P. Cunha, DO, FACOEP

Last reviewed on RxList 11/28/2017

Monoket (isosorbide mononitrate) is a vasodilator indicated for the prevention and treatment of angina pectoris due to coronary artery disease. The onset of action of oral isosorbide mononitrate is not sufficiently rapid for monoket to be useful in aborting an acute anginal episode. Common side effects of monoket include:

  • headache
  • fatigue
  • upper respiratory infection, pain
  • dizziness
  • nausea
  • increased cough
  • rash
  • abdominal pain, allergic reaction, cardiovascular disorders, chest pain, diarrhea, flushing, mood changes, and itching.

The recommended regimen of monoket tablets is 20 mg twice daily, with the doses seven hours apart. Monoket may interact with phosphodiesterase inhibitors, riociguat, other vasodilators, alcohol, and calcium channel blockers. Tell your doctor all medications and supplements you use. During pregnancy, monoket should be used only if prescribed. Tell your doctor if you are pregnant or become pregnant while taking monoket. It is unknown if monoket passes into breast milk. Consult your doctor before breastfeeding.

Our monoket (isosorbide mononitrate) tablets Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.


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Monoket Consumer Information

Get emergency medical help if you have signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have:

  • a light-headed feeling, like you might pass out;
  • worsening angina pain;
  • fast or slow heart rate; or
  • pounding heartbeats or fluttering in your chest.

Isosorbide mononitrate can cause severe headaches. These headaches may gradually become less severe as you continue to use nitroglycerin. Do not stop taking this medicine to avoid headaches. Ask your doctor before using any headache pain medication.

Common side effects may include:

  • headache; or
  • flushing (warmth, redness, or tingly feeling).

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Read the entire detailed patient monograph for Monoket (Isosorbide Mononitrate, USP)


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Monoket Professional Information


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)*

Dose 6 Placebo-Controlled Studies
Placebo 5 mg 10 mg 20 mg
Patients 160 54 52 159
Headache 6% (0%) 17% (0%) 13% (0%) 35% (5%)
Fatigue Upper Respiratory 2% (0%) 0% (0%) 4% (0%) 1% (0%)
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 Increased < 1% (0%) 0% (0%) 0% (0%) 3% (2%)
Cough < 1% (0%) 0% (0%) 2% (0%) < 1% (0%)
Rash Abdominal 0% (0%) 2% (2%) 0% (0%) < 1% (0%)
Pain Allergic < 1% (0%) 0% (0%) 2% (0%) 0% (0%)
Reaction Cardiovascular 0% (0%) 0% (0%) 2% (0%) 0% (0%)
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 Emotional 0% (0%) 0% (0%) 2% (0%) 0% (0%)
Lability 0% (0%) 2% (0%) 0% (0%) 0% (0%)
Pruritus 1% (0%) 2% (2%) 0% (0%) 0% (0%)
*Some individuals discontinued for multiple reasons.

Other adverse reactions, each reported by fewer than 1% of exposed patients, and in many cases of uncertain relation to drug treatment, were:

Cardiovascular: acute myocardial infarction, apoplexy, arrhythmias, bradycardia, edema, hypertension, hypotension, pallor, palpitations, tachycardia.

Dermatologic: sweating.

Gastrointestinal: anorexia, dry mouth, dyspepsia, thirst, vomiting, decreased weight.

Genitourinary: prostatic disorder.

Miscellaneous: amblyopia, back pain, bitter taste, muscle cramps, neck pain, pares thesia, susurrus aurium.

Neurologic: anxiety, impaired concentration, depression, insomnia, nervousness, nightmares, restlessness, tremor, vertigo.

Respiratory: asthma, dyspnea, sinusitis.

Extremely rarely, ordinary doses of organic nitrates have caused methemoglobinemia in normal-seeming patients; for further discussion of its diagnosis and treatment see OVERDOSAGE.

Read the entire FDA prescribing information for Monoket (Isosorbide Mononitrate, USP)

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© Monoket Patient Information is supplied by Cerner Multum, Inc. and Monoket Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.


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