Medications and Drugs
Pharmacy Author: Omudhome Ogbru, PharmD
Medical and Pharmacy Editor: Jay W. Marks, MD
GENERIC NAME: isosorbide mononitrate
BRAND NAMES: Imdur, Ismo, Monoket
DRUG CLASS AND MECHANISM: Isosorbide mononitrate is in the class of drugs
called nitrates that are used for treating and preventing angina. Other nitrates
include nitroglycerin (Nitrostat, NitroQuick, Nitrolingual, Nitro-Dur and
others) and isosorbide dinitrate (Isordil Titradose, Dilatrate-SR, Isochron).
Nitrates are vasodilators (dilators of blood vessels). Blood returning from the
body in the veins must be pumped by the heart through the lungs and into the
body's arteries against the high pressure in the arteries. In order to
accomplish this work, the heart's muscle must produce and use energy ("fuel")
which requires oxygen brought to the heart by the blood.
Angina pectoris
(angina) or "heart pain" is due to an inadequate flow of blood (and oxygen) to
the muscle of the heart. Nitrates, including isosorbide mononitrate, correct the
imbalance between the flow of blood and oxygen to the heart and the work that
the heart must do by dilating the arteries and veins in the body. Dilation of
the veins reduces the amount of blood that returns to the heart that must be
pumped. Dilation of the arteries lowers the pressure in the arteries against
which the heart must pump. As a consequence of both effects, the heart works
less and requires less blood and oxygen.
PRESCRIPTION: Yes
GENERIC AVAILABLE: Yes
PREPARATIONS: Tablets (immediate release): 10, 20 mg. Tablets (extended
release): 30, 60, 120 mg.
STORAGE: Isosorbide mononitrate should be stored at room temperature, 15-30 C
(59-86 F) in a tight, moisture- proof container.
PRESCRIBED FOR: Isosorbide mononitrate is used for the treatment and
prevention of angina. It can be used to decrease the frequency and severity of
anginal (chest pain) episodes and to reduce the need for sublingual (under the
tongue) nitroglycerin.
DOSING: The recommended dose of isosorbide mononitrate is 20 mg of immediate
release tablets twice daily. The two doses should be administered 7 hours apart
in order to avoid tolerance (decreased effect after several doses). The dose for
extended release tablets is 30-240 mg once daily.
DRUG INTERACTIONS: Sildenafil (Viagra), tadalafil (Cialis) and
vardenafil
(Levitra) increase the blood pressure lowering effects of isosorbide mononitrate
and may cause excessive reductions in blood pressure. Therefore, patients taking
isosorbide mononitrate should not receive sildenafil, tadalafil or vardenafil.
Severe reductions in blood pressure, especially when changing posture
(orthostatic hypotension), may occur when isosorbide mononitrate is combined
with calcium channel blockers
[for example, diltiazem (Cardizem, Dilacor, Tiazac and several others), verapamil
(Calan, Verelan, Verelan PM, Isoptin, Isoptin SR, Covera-HS)], which also reduce
blood pressure.
PREGNANCY: There are no adequate studies of isosorbide mononitrate in
pregnant women.
NURSING MOTHERS: It is not known if isosorbide mononitrate is excreted in
human breast-milk.
SIDE EFFECTS: Headaches are the most common side effect of isosorbide
mononitrate and usually are dose related (increase with higher doses). Flushing
may occur because isosorbide mononitrate dilates (enlarges) blood vessels.
Isosorbide mononitrate may cause a severe drop in blood pressure when rising
from a sitting position, causing dizziness, palpitations, and weakness. To
reduce the risk of low blood pressure, patients should rise slowly from a
sitting position.
Reference: FDA Prescribing Information
Last Editorial Review: 3/26/2009
Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
- Drug Interactions - Learn about potential drug interactions you may be exposed to. Drug interactions can occur with prescription drugs, OTC medication, vitamins, herbs, and supplements.
- Angina - Learn about the causes and symptoms of angina like pressure, heaviness, tightening, squeezing, and aching across the chest. There are two types of angina, stable (the most common) and unstable.
- Drugs: What You Should Know About Your Drugs - Find out what you should know about your drugs such as side effects, warnings and precautions, storage information, and if a generic version is as good as the brand name.
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