Isonit 20mg Tablet

Reviewed By Dr. Rajeev Sharma, MBA, MBBS

Last updated on 26 Feb 2026 | 04:10 PM (IST)

Isonit 20mg Tablet is used to prevent heart-related chest pain (angina). It works by relaxing and widening blood vessels so blood can flow more easily to the heart. This medicine will not treat an angina attack that has already begun.

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Isosorbide Mononitrate (20mg)

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General Information

Contains

Isosorbide Mononitrate (20mg)

Marketer

Rafflesia Life Sciences Pvt Ltd

Storage

Store below 30°C

The content is shown in English

Product introduction

Isonit 20mg Tablet may be taken with or without food. Your doctor will decide the dose and how often you should take them. This may change from time to time depending on how well they are working. You should take this medicine as it has been prescribed and keep taking it, even if you feel well. This medicine helps to prevent chest pain in the future. If you stop taking it, your risk of chest pain will increase, especially if you stop taking them suddenly. Lifestyle changes such as diet, exercise, and not smoking may help this medication work better.

You can develop tolerance to this medicine over time, which means that the same dose becomes less effective. You have to stick to a really specific dosing schedule to prevent this from happening.

The most common side effects include headache, flushing, upper respiratory tract infection, abdominal pain, allergic reaction, chest pain, and diarrhea. If these symptoms bother you or do not go away, your doctor may suggest ways of preventing or reducing them. Some can be reduced by taking painkillers, drinking plenty of fluids, and avoiding alcohol.

Before taking this medicine tell your doctor if you have low blood pressure, increased pressure in the eye (glaucoma), kidney disease, or heart failure. Also let your doctor know if you are taking any other medicines as some may affect, or be affected by, this medicine and some may be dangerous to take with it. You should not take any medicine for erectile dysfunction with this medicine. If you are pregnant or breastfeeding, ask your doctor if this medicine is suitable. Your doctor may regularly monitor your blood pressure and heart rate during the treatment with this medicine.

Uses of Isonit Tablet

Treatment of Angina (heart-related chest pain)

Benefits of Isonit Tablet

Treatment of Angina (heart-related chest pain)
Angina is chest pain caused by reduced blood flow to the heart muscles, usually due to narrowed coronary arteries. Isonit 20mg Tablet helps by relaxing and widening blood vessels, improving blood flow and oxygen delivery to the heart, which eases chest discomfort and reduces the chance of angina attacks.

Side effects of Isonit Tablet

Most side effects do not require any medical attention and disappear as your body adjusts to the medicine. Consult your doctor if they persist or if you’re worried about them

Common side effects of Isonit

Headache
Flushing (sense of warmth in the face, ears, neck and trunk)
Upper respiratory tract infection
Abdominal pain
Allergic reaction
Chest pain
Diarrhea

How to use Isonit Tablet

Take this medicine in the dose and duration as advised by your doctor. Swallow it as a whole. Do not chew, crush or break it. Isonit 20mg Tablet may be taken with or without food.

How Isonit Tablet works

Isonit 20mg Tablet is a nitrate. It dilates peripheral arteries and veins. Dilation of the veins promotes peripheral pooling of blood and decreases venous return to the heart, thereby reducing workload of heart. As a result, the heart muscle does not need as much blood and oxygen supply.

All substitutes for Isonit 20mg Tablet

For information purposes only. Consult a doctor before taking any medicine.

Quick tips

You have been prescribed Isonit 20mg Tablet for the prevention and treatment of heart-related chest pain (angina).
Eat healthy (low-fat, high-fiber, low-sodium diet), quit smoking, increase your physical activity, watch your weight and reduce stress.
Isonit 20mg Tablet may cause dizziness or sleepiness. Do not drive or do anything that requires concentration until you know how it affects you.
Do not consume alcohol while taking Isonit 20mg Tablet as it may cause increased dizziness.
It may cause headaches which usually go away after a few days of continued treatment. Inform your doctor if it persists.
You may develop tolerance to Isonit 20mg Tablet with time, meaning that the same dose may be less effective next time. Follow the prescribed dosing schedule to avoid this.
Stop taking medications (prescribed for erectile dysfunction) like sildenafil or tadalafil while on treatment with Isonit 20mg Tablet as it may cause low blood pressure.

Safety advice

Alcohol

CAUTION

Alcohol should be used with caution while taking Isonit 20mg Tablet.

Pregnancy

CONSULT YOUR DOCTOR

The safety of Isonit 20mg Tablet during pregnancy has not been established. There are no adequate and well-controlled studies in pregnant women, and animal data on reproductive toxicity are insufficient. Your doctor will weigh the benefits and any potential risks before prescribing.

Breast feeding

CONSULT YOUR DOCTOR

Isonit 20mg Tablet may be unsafe to use during breastfeeding. Limited human data suggests that the drug may pass into the breastmilk and harm the baby. It should be used only if the expected benefit outweighs the potential risk. Please consult your doctor.

Driving

UNSAFE

Isonit 20mg Tablet may decrease alertness, affect your vision, or make you feel sleepy and dizzy. Do not drive if these symptoms occur.

Kidney

SAFE IF PRESCRIBED

Isonit 20mg Tablet is safe to use in patients with kidney disease. No dose adjustment is recommended.
However, talk to your doctor if you have any underlying kidney disease.

Liver

SAFE IF PRESCRIBED

Isonit 20mg Tablet is safe to use in patients with liver disease. No dose adjustment is recommended.

Interaction with drugs

Taking Isonit with any of the following medicines can modify the effect of either of them and cause some undesirable side effects

Life-threatening

Sildenafil (Oral Route)

Do not consume Sildenafil with Isosorbide Mononitrate. If Sildenafil is essential, ensure a gap of at least 24 hours after discontinuing Isosorbide Mononitrate. Please consult your doctor.

Life-threatening

Tadalafil (Oral Route)

Do not consume Tadalafil with Isosorbide Mononitrate. If Tadalafil is essential, ensure a gap of at least 48 hours between taking Tadalafil and Isosorbide Mononitrate.

Life-threatening

Sildenafil (Oral Route)

Do not consume Sildenafil with Isosorbide Mononitrate. If Sildenafil is essential, ensure a gap of at least 24 hours after discontinuing Isosorbide Mononitrate. Please consult your doctor.

Life-threatening

Sildenafil (Injection Route)

Do not consume Sildenafil with Isosorbide Mononitrate. If Sildenafil is essential, ensure a gap of at least 24 hours after discontinuing Isosorbide Mononitrate. Please consult your doctor.

Life-threatening

Sildenafil (Injection Route)

Do not consume Sildenafil with Isosorbide Mononitrate. If Sildenafil is essential, ensure a gap of at least 24 hours after discontinuing Isosorbide Mononitrate. Please consult your doctor.

Frequently asked questions

Does Isonit 20mg Tablet affect heart rate?

Yes, Isonit 20mg Tablet may affect the heart rate. Isonit 20mg Tablet causes a decrease in blood pressure. This decrease in blood pressure further causes a decrease in the heart rate (bradycardia). In some cases, it may also cause an increase in the heart rate (tachycardia). Consult your doctor in case you do not feel well after taking this medicine or if you notice a change in your heart rate.

What if I forget to take a dose of Isonit 20mg Tablet?

You can take the forgotten dose of Isonit 20mg Tablet if you remember it within 12 hours. However, if you remember it after 12 hours of the scheduled time, then skip the missed dose and continue with the next dose.

Can I stop taking Isonit 20mg Tablet after sometime?

No, do not stop taking this medicine without talking to your doctor. Stopping it suddenly may increase your chances of having an anginal attack. If you have any concerns regarding Isonit 20mg Tablet consult your doctor.

What are the symptoms of an overdose of Isonit 20mg Tablet?

Taking more than the recommended dose of Isonit 20mg Tablet may cause throbbing headache, reddening of the skin, chills along with sweating, nausea, vomiting, and a fast heartbeat. Seek emergency help and consult your doctor immediately if you take more than the recommended dose of this medicine.

Can Isonit 20mg Tablet be taken at night?

Depending upon the dose, your doctor may recommend you to take this medicine once or twice daily. When a single dose is recommended, then it is preferred to be taken in the morning. If taking it twice a day, maintain a gap of 7 hours between the two doses. This helps decrease the chances of Isonit 20mg Tablet becoming ineffective (tolerance) after some time.

Does Isonit 20mg Tablet lower BP?

Yes, Isonit 20mg Tablet can cause a fall in blood pressure. This medicine widens the blood vessels and decreases the resistance in them, causing a fall in blood pressure. This fall in blood pressure may in turn decrease the heartbeat which can lead to angina. This medicine should be avoided in people who already have low blood pressure. Discuss with your doctor if you have any concerns.

Can I take sildenafil while taking Isonit 20mg Tablet?

No, you should not take sildenafil along with Isonit 20mg Tablet. Both these medicines lower blood pressure and belong to the same class. Taking these two medicines together may cause a severe decrease in blood pressure, fainting, and even a heart attack. Along with this, also avoid taking other medicines belonging to similar classes such as vardenafil and tadalafil.

Fact Box

Chemical Class

Isosorbides

Habit Forming

Therapeutic Class

CARDIAC

Action Class

Nitric Oxide (NO) Donors

References

Opie LH, Horowitz JD. Nitrates and Newer Antianginals β-Blocking Agents. In: Opie LH, Gersh BJ, editors. Drugs for the Heart. 8th ed. Philadelphia, Pennsylvania: Elsevier Saunders; 2013. p. 47.
Briggs GG, Freeman RK, editors. A Reference Guide to Fetal and Neonatal Risk: Drugs in Pregnancy and Lactation. 10th ed. Philadelphia, PA: Wolters Kluwer Health; 2015. p. 744.
Central Drugs Standard Control Organisation (CDSCO). [Accessed 19 Mar. 2019] (online) Available from:
Central Drugs Standard Control Organisation. Isosorbide Mononitrate. [Accessed 05 Jul. 2023]. (online) Available from:
National Health Services. Isosorbide mononitrate and isosorbide dinitrate. [last Reviewed: 1 Jul. 2021]. [Accessed 05 Jul. 2023]. (online) Available from:
Isosorbide mononitrate tablet [Prescribing Information]. Dupnitsa, Bulgaria: Balkanpharma - Dupnitsa AD; 2022. [Accessed 05 Jul. 2023]. (online) Available from:

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Tata 1mg's sole intention is to ensure that its consumers get information that is expert-reviewed, accurate and trustworthy. However, the information contained herein should NOT be used as a substitute for the advice of a qualified physician. The information provided here is for informational purposes only. This may not cover everything about particular health conditions, lab tests, medicines, all possible side effects, drug interactions, warnings, alerts, etc. Please consult your doctor and discuss all your queries related to any disease or medicine. We intend to support, not replace, the doctor-patient relationship.

Marketer details

Name: Rafflesia Life Sciences Pvt Ltd
Address: B-3334, B Block Gali No. 87, Apex Road, Sant Nagar, Burari Delhi New Delhi Dl 110084 India

Vendor Details

Country of origin: India

Lab tests offered by us

Why we need a prescription?

Provide right medicines

Prescriptions are complex documents. We proof read and recheck at various steps to provide you the right medication in the correct form and dose

In accordance with the law

Most medicines cannot be sold without a valid prescription, as per the Drugs and Cosmetics Act, 1940 and Rules, 1945

Isonit 20mg Tablet

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General Information

Contains

Marketer

Storage

Product introduction

Uses of Isonit Tablet

Benefits of Isonit Tablet

Side effects of Isonit Tablet

How to use Isonit Tablet

How Isonit Tablet works

All substitutes for Isonit 20mg Tablet

Isotrate 20 Tablet

IsoMIN 20mg Tablet

Ismo 20 Tablet

Monotrate 20 Tablet

Monit 20 Tablet

Quick tips

Safety advice

Alcohol

Pregnancy

Breast feeding

Driving

Kidney

Liver

Interaction with drugs

Sildenafil (Oral Route)

Tadalafil (Oral Route)

Sildenafil (Oral Route)

Sildenafil (Injection Route)

Sildenafil (Injection Route)

Frequently asked questions

Does Isonit 20mg Tablet affect heart rate?

What if I forget to take a dose of Isonit 20mg Tablet?

Can I stop taking Isonit 20mg Tablet after sometime?

What are the symptoms of an overdose of Isonit 20mg Tablet?

Can Isonit 20mg Tablet be taken at night?

Does Isonit 20mg Tablet lower BP?

Can I take sildenafil while taking Isonit 20mg Tablet?

Fact Box

Chemical Class

Habit Forming

Therapeutic Class

Action Class

References

Want to know more

Have issue with the content

Disclaimer

Marketer details

Vendor Details

Lab tests offered by us

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