Nitrosorbide

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Nitrosorbide

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Medically reviewed

Marina Burgos

Last updated on 10/01/2026

This page provides general, reference-level information compiled from official medical sources. It is not a substitute for professional medical advice, diagnosis, or treatment. For decisions about your health, please consult a qualified healthcare professional.

Overview of Nitrosorbide

Property Description
Active Ingredient Isosorbide Dinitrate (ISDN)
Form Tablet (oral, sublingual), Capsule (extended-release), Injection
Pharmacological Class Organic Nitrate; Vasodilator; Antianginal Agent
General Purpose Reduction of cardiac workload
Origin Synthetic compound

What Type of Medicine is Nitrosorbide and What is it Made Of?

Nitrosorbide is the trade name for a prescription-only medication defined by its sole active ingredient, Isosorbide Dinitrate (ISDN), which is definitively classified as an organic nitrate. This medicine belongs to the broader pharmacological class of antianginal agents and vasodilators, with a primary use in managing chest pain. The trade name Nitrosorbide is clinically recognized for delivering the ISDN compound, which is also marketed under other trade names such as Isordil and Sorbitrate, depending on the manufacturer and region.

The core identity of this drug lies in the synthetic compound Isosorbide Dinitrate, which acts as a prodrug, meaning it requires biotransformation within the body to liberate the therapeutically active agent, Nitric Oxide (NO). As a vasodilator, its primary function is to trigger the relaxation of smooth muscle surrounding the body's blood vessels. The final pharmaceutical preparations utilize various inactive excipients to create stable dosage forms, such as tablets and capsules, for efficient delivery.


What are the Physical Forms of Nitrosorbide and Its General Purpose?

Nitrosorbide (Isosorbide Dinitrate) is available in several pharmaceutical preparations, including standard oral tablets, specialized sublingual tablets (for rapid absorption), and extended-release capsules, to suit different clinical needs. The general purpose of the medication is to alleviate heart strain by causing systemic vessel relaxation, thereby reducing the heart’s overall workload. This effect is pharmacologically confirmed to be beneficial in improving oxygen supply to the myocardium (heart muscle).

The availability of both rapid-acting (sublingual) and long-acting (extended-release) forms represents a key differentiating feature for the drug substance, allowing it to be used for the short-term relief of chest pain and for prophylactic maintenance therapy. The therapeutic benefit stems from the drug's ability to reduce both the resistance the heart pumps against and the volume of blood returning to the heart (preload and afterload). This fundamental action is crucial for managing symptoms related to restricted coronary blood flow, such as angina pectoris.

Regulatory References

  1. NIH MedlinePlus

What side effects are possible with Nitrosorbide?

Possible side effects and safety information

The safety profile of Nitrosorbide (Isosorbide Dinitrate) is characterized by effects directly related to its role as an organic nitrate and vasodilator, and are generally classified by government regulatory authorities (SmPC, FDA) according to frequency and System Organ Class (SOC).


Officially Documented Adverse Reactions

The most frequent adverse events are associated with the medicine's blood vessel-relaxing activity:

  • Very Common (≥1/10): The most frequently documented effect is headache. Regulatory documents note this is often severe at treatment initiation but typically diminishes in intensity with continued use.
  • Common (1/100 to <1/10): Reactions include hypotension (low blood pressure), orthostatic hypotension (dizziness upon standing), reflex tachycardia (increased heart rate), and flushing. These effects may be more apparent at the start of therapy or following a dosage increase.
  • Uncommon/Rare: Less frequent effects include nausea, vomiting, and allergic skin reactions. Rare, severe reactions documented in regulatory labeling include Stevens-Johnson Syndrome and methemoglobinemia.

Serious Safety Considerations

Official labeling defines severe hypotension leading to collapse or syncope (fainting) as a serious adverse reaction. A paradoxical effect noted is the potential for aggravation of angina pectoris (chest pain) in certain patients, often associated with a severe drop in blood pressure.

Safety-Related Restrictions

Regulatory documents highlight absolute constraints for use. The medicine is strictly contraindicated for use with Phosphodiesterase Type-5 (PDE5) inhibitors (such as sildenafil or tadalafil) due to the risk of profound, life-threatening hypotension. Caution is also advised in older adults due to increased sensitivity to hypotensive effects and in patients with severe hepatic or renal impairment.

Overdose and Emergency Response

Overdose and When to Seek Help

The official regulatory documents define Nitrosorbide (Isosorbide Dinitrate) overdose as a serious event resulting from an exaggerated extension of its primary effects. Immediate medical attention is required upon suspicion or appearance of overdose signs. Patients must seek emergency medical attention or contact emergency services immediately as stated in official labeling.

Documented Manifestations

Overdose presentations involve severe physiological consequences. The most significant documented clinical signs include profound hypotension (prompt and substantial fall in blood pressure) and hemodynamic collapse. Other systemic manifestations described in the labeling include severe and persistent throbbing headache, vertigo, confusion, palpitation, and gastrointestinal effects like bloody diarrhea.

Severe Outcomes and Management

A massive overdose can be fatal. Severe consequences include seizures, coma, and a specific risk of methemoglobinemia, a life-threatening blood condition that requires specialized intervention with methylene blue.

Since no specific antagonist to the drug’s effects is known, management focuses on symptomatic and supportive treatment. This includes interventions such as increasing central fluid volume through intravenous normal saline infusion or passive elevation of the patient's legs. Regulatory guidance explicitly states that epinephrine and other arterial vasoconstrictors must be avoided as part of the emergency protocol. Hospital monitoring and continuous cardiac observation may be required.

Therapeutic Uses of Nitrosorbide

Main Uses and Benefits of Nitrosorbide

Nitrosorbide (Isosorbide Dinitrate) is used in situations involving certain distressing symptoms and is primarily applied to manage conditions presenting with acute or episodic manifestations related to cardiac function. This medicine is commonly used to address symptoms that interfere with daily comfort. Specifically, its therapeutic applications include the prevention of angina pectoris (chest pain) due to coronary artery disease and, when used with other medicines, conditions involving episodic or fluctuating manifestations, such as heart failure. Regular use generally assists with managing symptom clusters that may become intense or disruptive, contributing to improved comfort during periods of heightened symptoms.

The benefit provided includes supportive relief which helps ease the overall symptom burden in situations involving temporary physiological imbalance. It is relevant in contexts involving heightened systemic burden. It supports the patient during difficult episodes by easing distress and is commonly used when short-term symptomatic assistance is needed.

In the context of heart failure, this medicine may assist with maintaining functional stability. It supports the patient during difficult episodes by easing distress and is commonly used when short-term symptomatic assistance is needed. This medicine is not intended for use as a short-term symptomatic assistance to treat an acute angina attack that has already started.

Quick Fact: Relief for symptoms related to physical discomfort

Regulatory References

  1. NIH MedlinePlus overview

Eligibility and Restrictions for Use

Who Can and Cannot Use Nitrosorbide?

Eligibility for Nitrosorbide (Isosorbide Dinitrate) is strictly defined by regulatory bodies based on known contraindications, specific population risks, and safety data.

Absolute Contraindications

The medication must not be used by patients who have a known hypersensitivity to nitrates or nitrites. The most critical restriction is the absolute prohibition of use in patients taking Phosphodiesterase Type 5 (PDE5) Inhibitors (e.g., sildenafil) or the soluble Guanylate Cyclase (sGC) stimulator riociguat, as this combination can cause severe, life-threatening hypotension.

Age and Physiological Restrictions

Population Group Eligibility Status (Regulatory Labeling)
Pediatric Patients (Under 18) Safety and effectiveness have not been established; use is not authorized.
Older Adults (Geriatric) Caution is advised due to the higher frequency of decreased renal or hepatic function.
Pregnancy Use is permitted only if the potential benefit justifies the potential risk to the fetus.
Acute Cardiac Events Not recommended for the treatment of acute myocardial infarction (MI) or acute congestive heart failure (CHF).

Conditional Use

Use requires caution in patients who are hypotensive, volume depleted, or have certain pre-existing conditions like hypertrophic cardiomyopathy.

What should I know about interactions with other medicines?

Official Interaction Restrictions

Co-administration of Nitrosorbide (Isosorbide Dinitrate) is Contraindicated with several classes of medicinal products due to the risk of severe, life-threatening hypotension. This absolute prohibition applies to Phosphodiesterase 5 (PDE5) Inhibitors (including Sildenafil, Tadalafil, Vardenafil, and Avanafil) and Soluble Guanylate Cyclase (sGC) Stimulators (such as Riociguat). These combinations present a major pharmacodynamic risk by excessively augmenting the drug’s vasodilatory effect.

Administration Timing and Potentiation

For patients who require nitrate therapy after taking PDE5 Inhibitors, mandatory time separation is officially documented. A minimum interval of 24 hours must elapse following Sildenafil or Vardenafil use, and a 48-hour interval is required after Tadalafil use.

The hypotensive effects are additive with concurrent use of Antihypertensive Drugs (e.g., beta-blockers, calcium channel blockers, ACE-inhibitors), other vasodilators, and Phenothiazines, requiring observation for possible enhancement of low blood pressure. Alcohol (Ethanol) may also potentiate the hypotensive and vasodilating effects.

A different type of interaction exists with Dihydroergotamine, where Isosorbide Dinitrate may increase the blood level of Dihydroergotamine and its associated hypertensive effect. Furthermore, regulatory documents recommend caution for interaction risk in patients with severe hepatic or renal impairment due to the potential for drug accumulation.

Mechanism of Action

The mechanism of Nitrosorbide (Isosorbide Dinitrate) is initiated by its classification as a prodrug that is metabolized inside vascular cells to release the signaling molecule, Nitric Oxide ( NO). NO subsequently binds to and activates the enzyme soluble guanylyl cyclase ( sGC), triggering the cGMP pathway within the smooth muscle. This molecular cascade promotes the dephosphorylation of the myosin light chain, leading to the relaxation of the muscle tissue that forms the walls of blood vessels.

The resulting smooth muscle relaxation causes widespread vasodilation, which is most pronounced in the venous system (capacitance vessels). By increasing the capacity of the veins, the mechanism significantly decreases the volume of blood returning to the heart, a physiological adjustment known as reducing preload. Concurrently, dilation of the arterioles reduces the resistance the heart must overcome to pump blood, reducing afterload. The overall consequence is a mechanical decrease in the ventricular work index.

A mechanistic constraint is the development of nitrate tolerance, a time-dependent attenuation of the physiological response with continuous exposure. This constraint necessitates a restoration period to allow the reversal of the desensitization and the regeneration of necessary biological co-factors.

Dosage and Administration Information

Nitrosorbide, which contains the active ingredient isosorbide dinitrate, is administered via several routes for distinct usage patterns. The administration routes include oral (swallowed tablets or capsules), sublingual (dissolved under the tongue), and intravenous (IV) infusion for acute care settings.

Administration Pattern and Scheduling

For scheduled long-term maintenance, the oral immediate-release tablets are typically initiated at 5 mg to 20 mg and maintained in the range of 10 mg to 40 mg, usually administered two or three times daily. Sublingual tablets, typically dosed at 2.5 mg to 5 mg, are intended for intermittent use when a rapid effect is desired, such as for anticipated physical exertion.

A critical requirement for all chronic oral regimens is the inclusion of a mandatory daily dose-free interval of 14 hours or more. This cyclic use pattern is intended to prevent the development of drug tolerance, ensuring the medicine retains its efficacy over time. The dosing schedule must be structured to accommodate this specific time interval without medication.

Procedural and Special Instructions

Proper use dictates that extended-release formulations must be swallowed whole and should not be crushed or chewed, as this compromises the sustained release mechanism. Conversely, sublingual tablets must be allowed to dissolve fully under the tongue. If a scheduled oral dose is missed, it is advised to take the next dose at the regularly scheduled time, rather than attempting to double the amount to compensate. There are no specific recommendations for dosage adjustments for older adults or those with kidney or liver impairment, and the use of this medicine is generally not established for pediatric patients.

Recent Clinical Evidence

Evidence for Use in Preventing Angina Pectoris

Research related to the use of Nitrosorbide for preventing chest pain (angina pectoris) includes short-to-medium term Randomized Controlled Trials (RCTs). These studies monitored adult populations with stable angina and often used double-blind, placebo-controlled designs. Researchers examined outcomes related to physical discomfort and daily functioning, such as measuring the frequency of anginal episodes or exercise capacity. The evidence base includes findings that described varied results when compared to placebo in some early trials. The research record describes limitations due to nitrate tolerance, where the initial pharmacological response may diminish over time in chronic regimens.


Evidence for Use in Chronic Heart Failure Management

Research exploring the use of Nitrosorbide in chronic heart failure has involved large-scale, pivotal RCTs. This research examined the use of the medicine when administered as part of a combination therapy with another specific vasodilator (hydralazine). Key outcomes monitored included all-cause mortality and the frequency of heart failure-related hospitalizations. Studies described observed patterns in long-term survival and hospitalization rates for populations receiving this combination therapy. The most significant findings are derived from trials where the medicine was evaluated as part of this fixed-dose combination.


Gaps and Uncertainties in the Research Record

The evidence is highly context-specific. The long-term effects are not fully established beyond the one-to-two-year observation periods in the pivotal heart failure trials. Furthermore, the evidence remains limited for the use of Nitrosorbide alone for heart failure, or in combination with other treatments not specifically studied. For angina prevention, research is ongoing to better characterize dosing schedules associated with maintaining the observed patterns, especially considering the challenge of nitrate tolerance.

Key Studies & References

  1. ISOSORBIDE DINITRATE tablet - Label from DailyMed, NIH (Provides regulatory context for Angina and tolerance limitation)

Frequently Asked Questions (FAQ)

Common questions about Nitrosorbide (FAQ)


Q: Is Nitrosorbide the same as nitroglycerin?

A: Nitrosorbide contains the active ingredient isosorbide dinitrate, which belongs to the same class of medicines, the organic nitrates, as nitroglycerin (glyceryl trinitrate). Official documents state that individuals who have a known allergy to nitroglycerin or isosorbide mononitrate are contraindicated from using Nitrosorbide.


Q: Is Nitrosorbide a blood pressure medicine?

A: Nitrosorbide is classified as an antianginal agent and a vasodilator, meaning it widens blood vessels. This mechanism does lead to a reduction in blood pressure, and hypotension (low blood pressure) is listed in official documents as a common side effect. Its effects are noted as additive with other medicines prescribed for high blood pressure, but its primary authorized purpose relates to managing heart work.


Q: What is the difference between Nitrosorbide and a beta-blocker?

A: Nitrosorbide is an organic nitrate that primarily works by directly relaxing the smooth muscle in blood vessel walls. Beta-blockers are a different pharmacological class of medicine that generally affect the heart by reducing heart rate and the force of its contractions. Official warnings note that taking Nitrosorbide concurrently with a beta-blocker may increase the blood pressure-lowering effect.


Q: Can people with kidney problems use Nitrosorbide?

A: Official regulatory documents advise that the medicine should be used with caution in people who have severe renal (kidney) impairment. This caution is noted because there is a potential for the active ingredient or its breakdown products to accumulate in the body if the kidneys are not functioning optimally.


Q: Is Nitrosorbide safe for older adults?

A: Official information advises that caution is necessary when Nitrosorbide is used in older adults (geriatric patients). The caution is related to potential increased sensitivity to hypotensive effects and the general possibility of decreased renal or hepatic function in this age group.


Q: What if I accidentally take too much Nitrosorbide?

A: Symptoms of an overdose are related to excessive blood vessel widening, which can cause severe low blood pressure. Official documents list severe throbbing headache, confusion, a rapid heart rate, fainting (syncope), and prolonged dizziness as possible signs of overexposure. Overdose can also rarely lead to a serious blood condition called methemoglobinemia. Official warnings advise seeking emergency medical attention if an overdose is suspected.


Q: Is Nitrosorbide safe for people with liver disease?

A: Official regulatory documents advise that the medicine should be used with caution in people who have severe hepatic (liver) impairment. This caution is advised because the drug is processed in the liver, and severe impairment could potentially cause the medicine or its metabolites to accumulate.


Q: How quickly does Nitrosorbide start working?

A: The onset of action is dependent on the form used. For the standard immediate-release oral tablets, the anti-anginal effect typically begins about 1 hour after being swallowed. The sublingual form, which dissolves under the tongue, is intended to provide a much more rapid effect (within minutes).


Q: How long do the effects of Nitrosorbide last?

A: The duration of effect varies based on the dosage form and specific regimen. For the immediate-release oral form, the anti-anginal activity has been shown to last for up to 8 hours after a single dose. However, official regulatory instructions limit continuous effect to about 12 hours per day to manage tolerance development.


Q: Can Nitrosorbide cause problems with sleeping?

A: Official regulatory documents do not list insomnia or sleep problems as a common side effect of Nitrosorbide. However, common side effects related to the central nervous system, such as headache and dizziness, are documented and could potentially interfere with sleep for some individuals.


Q: Does Nitrosorbide interact with any common over-the-counter pain relievers?

A: Official patient information notes that some over-the-counter pain relievers, such as aspirin and acetaminophen, are often used to relieve the headaches associated with Nitrosorbide use without negatively affecting its intended function. Regulatory documents do not include detailed interaction data for all common pain relievers.


Q: Are there foods or drinks I should avoid while taking Nitrosorbide?

A: Regulatory documents explicitly advise against the use of alcohol (ethanol) because it may significantly increase the blood vessel-widening and blood pressure-lowering effects of the medicine. No specific solid foods are officially noted as needing to be avoided.


Q: Is Nitrosorbide considered a long-term treatment?

A: Yes, Nitrosorbide is indicated for the prevention of angina pectoris and is often administered via a 'scheduled long-term maintenance' or 'chronic oral regimen' in its long-acting forms. Research also examined the medicine over long periods as part of a combination therapy for chronic heart failure.


Q: Does taking Nitrosorbide require any special monitoring?

A: For long-term outpatient use, routine blood tests or specialized monitoring are not universally mandated in official documents. However, if the medicine is used in acute heart conditions, such as myocardial infarction, careful hemodynamic monitoring (measuring blood flow and pressure) may be used or is necessary to avoid potentially severe drops in blood pressure.


Q: Can Nitrosorbide be used for conditions other than heart-related problems?

A: Official labeling only specifies the use of Nitrosorbide for conditions related to heart disease: the prevention and treatment of angina pectoris (chest pain) and management of chronic heart failure as part of a combination therapy. The authorized indications do not include use for conditions outside of these areas.


Q: Does Nitrosorbide affect the ability to drive or operate machinery?

A: Official regulatory documents indicate that Nitrosorbide has a minor influence on the ability to drive or use machines. Individuals are advised that they should not drive or operate machinery if they experience common side effects such as headache, dizziness, or tiredness.


Q: Is Nitrosorbide a generic or a brand-name drug?

A: Nitrosorbide is a trade name (brand name) for the active ingredient isosorbide dinitrate. The active ingredient itself is widely available as a generic medication and is also marketed under various other trade names globally.


Q: Will Nitrosorbide stop working over time (tolerance)?

A: Yes, official documents describe a biological constraint called nitrate tolerance where the drug's effectiveness can diminish with continuous exposure. To help minimize this effect, a mandatory daily dose-free interval of 14 hours or more is required in the prescribed dosing schedule.


Q: What steps should I take if I experience a severe side effect from Nitrosorbide?

A: Official warnings advise that seeking emergency medical attention is necessary if an individual experiences signs of a severe allergic reaction, symptoms of profound low blood pressure (such as a light-headed feeling like they might faint), or if their chest pain (angina) appears to worsen dramatically.


Q: Is it possible to be allergic to Nitrosorbide?

A: Yes, regulatory documents list a known hypersensitivity or allergy to nitrates, nitrites, or isosorbide dinitrate as an absolute contraindication (must not be used). Symptoms of an allergic reaction may include rash, swelling of the face, tongue, or throat, or trouble breathing.


Q: Can I take other heart medications along with Nitrosorbide?

A: Yes, regulatory documents describe the use of Nitrosorbide as part of a combination therapy with other vasodilators for managing chronic heart failure. However, caution is advised because the blood pressure-lowering effects of Nitrosorbide are additive when taken concurrently with other antihypertensive or heart medicines.


Q: Why do some people use Nitrosorbide 'as needed' and others daily?

A: The use pattern is based on the pharmaceutical form. The sublingual tablets are designed for intermittent, 'as needed' use when a rapid effect is desired, such as before anticipated physical exertion. The standard oral tablets and extended-release capsules are intended for a scheduled daily maintenance regimen to help prevent attacks.


Q: How is Nitrosorbide different from isosorbide dinitrate or isosorbide mononitrate?

A: Nitrosorbide is a trade name for the active ingredient isosorbide dinitrate (ISDN). Isosorbide mononitrate (ISMN) is the primary active compound that ISDN is broken down into inside the body, and it is also manufactured as a separate medicine. Both are organic nitrates that differ in their duration of action and typical dosing schedules.


Q: Do you need a prescription to get Nitrosorbide?

A: Yes, according to all regulatory documents, Nitrosorbide in all its available forms (oral tablets, sublingual tablets, and extended-release capsules) is strictly a prescription-only medication.


Q: Is Nitrosorbide addictive?

A: Official documents do not classify the medicine as addictive in the manner of controlled substances. However, warnings note that physical dependence can develop after long-term, high-dose use. Abruptly stopping the medicine in such cases has been associated with adverse events, including chest pain.


Q: What are the official guidelines regarding Nitrosorbide and performing physical activity?

A: The official guidance relates directly to managing chest pain. The rapid-acting sublingual form is specifically indicated to be taken 15 minutes prior to activity that is likely to cause an anginal (chest pain) episode. No general guidelines on exercise are noted beyond this.


Q: Do research studies suggest any specific effectiveness for certain patient groups?

A: The core research supporting the use of the medicine focuses on two main groups: adult populations with stable angina and patients with chronic heart failure who received the medicine as part of a specific combination therapy (with hydralazine). Effectiveness information is highly context-specific to these groups.


Q: What is the primary way Nitrosorbide helps the heart?

A: The primary way the medicine helps the heart is by relaxing the walls of the blood vessels, a process called vasodilation. This action reduces the amount of blood returning to the heart (reducing preload) and lessens the resistance the heart must pump against (reducing afterload), thereby helping to decrease the overall workload on the heart muscle.


Q: Is Nitrosorbide listed on any official 'do not use' lists?

A: Regulatory documents list several situations where the medicine must not be used (absolute contraindications). The most critical prohibitions are for individuals with a known allergy to nitrates, and for patients taking Phosphodiesterase Type 5 (PDE5) inhibitors (like sildenafil) or the sGC stimulator riociguat.


Q: What is the risk of fainting when taking Nitrosorbide?

A: Fainting (syncope) is listed in official documents as a serious adverse reaction, which is typically a result of severe low blood pressure (hypotension). Orthostatic hypotension, which is dizziness or light-headedness upon standing, is a common effect that may occur in some patients.


Q: How is Nitrosorbide typically supplied (e.g., tablet, capsule)?

A: The medicine is typically supplied in different pharmaceutical preparations designed for specific uses. These forms include standard oral tablets, specialized sublingual tablets (for dissolving under the tongue), and extended-release capsules.

How should Nitrosorbide be stored and disposed of?

Storage and Disposal Requirements

Nitrosorbide (Isosorbide Dinitrate) must be stored strictly according to official regulatory documentation to maintain its stability.

Storage Conditions

Requirement Specific Condition
Temperature Store at controlled room temperature (20 C to 25 C / 68 F to 77 F).
Protection Protect from light and excessive moisture; do not freeze.
Packaging Keep the medicine in a light-resistant, tight container and keep the lid tightly closed.
Child Safety Store the medicine out of the reach and sight of children.

Disposal Instructions

Outdated or unused Nitrosorbide should be disposed of by consulting a pharmacist or healthcare professional. Official guidance advises that unused medicine must not be disposed of via wastewater or household waste.

Attention! Always consult to a doctor or pharmacist before using pills or medicines.

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