Isosorbide Dinitrate 40mg Tablets
It is used to prevent chest pain (angina pectoris) in people with heart disease.It may be given to you for other reasons. Talk with the doctor.
Drug Class
Antianginal, Vasodilator
Pharmacologic Class
Organic Nitrate
Pregnancy Category
Category C
FDA Approved
Jan 1951
DEA Schedule
Not Controlled
Overview
What is this medicine?
Isosorbide dinitrate is a medication used to prevent chest pain (angina) caused by heart disease. It works by relaxing blood vessels, which helps more blood and oxygen reach your heart, and reduces the heart's workload.
How to Use This Medicine
Taking Your Medication Correctly
To use this medication safely and effectively, follow your doctor's instructions carefully. Read all the information provided to you and adhere to the prescribed regimen. Do not stop taking this medication abruptly without consulting your doctor, as this may increase your risk of side effects. If you need to discontinue this medication, your doctor will guide you on how to taper off slowly.
Storing and Disposing of Your Medication
To maintain the quality and safety of your medication, store it at room temperature, protected from light, and in a dry place. Avoid storing it in a bathroom. Keep the container tightly closed and store all medications in a secure location, out of the reach of children and pets.
Managing Missed Doses
If you miss a dose, take it as soon as you remember. However, if it is close to the time for your next scheduled dose, skip the missed dose and resume your regular dosing schedule. Do not take two doses at the same time or take extra doses to make up for the missed one.
To use this medication safely and effectively, follow your doctor's instructions carefully. Read all the information provided to you and adhere to the prescribed regimen. Do not stop taking this medication abruptly without consulting your doctor, as this may increase your risk of side effects. If you need to discontinue this medication, your doctor will guide you on how to taper off slowly.
Storing and Disposing of Your Medication
To maintain the quality and safety of your medication, store it at room temperature, protected from light, and in a dry place. Avoid storing it in a bathroom. Keep the container tightly closed and store all medications in a secure location, out of the reach of children and pets.
Managing Missed Doses
If you miss a dose, take it as soon as you remember. However, if it is close to the time for your next scheduled dose, skip the missed dose and resume your regular dosing schedule. Do not take two doses at the same time or take extra doses to make up for the missed one.
Lifestyle & Tips
- Take this medication exactly as prescribed by your doctor. Do not stop taking it suddenly.
- It is important to have a 'nitrate-free' period each day (usually 10-14 hours) to prevent the medication from losing its effectiveness (tolerance). Your doctor will explain how to schedule your doses.
- Avoid alcohol while taking this medication, as it can increase dizziness and lower blood pressure.
- Get up slowly from a sitting or lying position to avoid dizziness or fainting.
- Headache is a common side effect and often indicates the medication is working. It usually lessens with continued use. Over-the-counter pain relievers may help.
- Do not take this medication if you are also taking medications for erectile dysfunction (e.g., sildenafil, tadalafil) or riociguat, as this can cause a dangerous drop in blood pressure.
Available Forms & Alternatives
Available Strengths:
- Isosorbide Dinitrate 30mg Oral Tabs
- Isosorbide Dinitrate 5mg Oral Tabs
- Isosorbide Dinitrate 20mg Tablets
- Isosorbide Dinitrate 10mg Oral Tabs
- Isosorbide Mononitrate 10mg Tabs
- Isosorbide Mononitrate 120mg ER Tab
- Isosorbide Mononitrate 30mg ER Tabs
- Isosorbide Mononitrate 60mg ER Tabs
- Isosorbide Mononitrate 60mg ER Tabs
- Isosorbide Dinitrate 40mg Tablets
- Isosorbide Mononitrate 30mg ER Tabs
- Isosorbide Mononitrate 120mg ER Tab
- Isosorbide Mononitrate 20mg Tabs
- Isosorbide Mononitrate 20mg Tabs
- Isosorbide Mononitrate 10mg Tabs
Dosing & Administration
Adult Dosing
Standard Dose:
20 mg to 40 mg orally two or three times daily, with a nitrate-free interval of 14 hours daily.
Dose Range:
20 - 40 mg
Condition-Specific Dosing:
anginaProphylaxis:
20 mg to 40 mg orally two or three times daily. Doses should be administered 5 hours apart (e.g., 8 AM, 1 PM, 6 PM) to allow for a nitrate-free interval to prevent tolerance.
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established
Child:
Not established
Adolescent:
Not established
Dose Adjustments
Renal Impairment:
Mild:
No specific dose adjustment recommended.
Moderate:
Use with caution; consider lower initial doses and titrate slowly.
Severe:
Use with caution; consider lower initial doses and titrate slowly due to potential for accumulation of active metabolites.
Dialysis:
Not well studied; use with caution. Active metabolites may accumulate.
Hepatic Impairment:
Mild:
No specific dose adjustment recommended.
Moderate:
Use with caution; consider lower initial doses and titrate slowly due to extensive hepatic metabolism.
Severe:
Use with caution; consider lower initial doses and titrate slowly due to extensive hepatic metabolism. Increased risk of adverse effects.
Pharmacology
Mechanism of Action
Isosorbide dinitrate is an organic nitrate that causes relaxation of vascular smooth muscle. It is metabolized to nitric oxide (NO), which activates guanylyl cyclase, leading to an increase in cyclic guanosine monophosphate (cGMP). Increased cGMP results in dephosphorylation of myosin light chains, causing relaxation of smooth muscle cells. This leads to venodilation (reducing preload) and arterial dilation (reducing afterload), decreasing myocardial oxygen demand and improving myocardial blood flow.
Pharmacokinetics
Absorption:
Bioavailability:
Approximately 20-25% (due to significant first-pass metabolism)
Tmax:
Oral tablet: 1 hour
FoodEffect:
Food may delay absorption but does not significantly affect the extent of absorption.
Distribution:
Vd:
Not readily available, but widely distributed.
ProteinBinding:
Not extensively protein bound (less than 10%).
CnssPenetration:
Limited
Elimination:
HalfLife:
Parent drug: 1 hour; Isosorbide-2-mononitrate: 1.5-2 hours; Isosorbide-5-mononitrate: 4-6 hours
Clearance:
High systemic clearance.
ExcretionRoute:
Primarily renal (as metabolites).
Unchanged:
Less than 1% (parent drug).
Pharmacodynamics
OnsetOfAction:
Oral tablet: 20-60 minutes
PeakEffect:
Oral tablet: 1-2 hours
DurationOfAction:
Oral tablet: 4-6 hours (up to 8 hours for sustained release)
Safety & Warnings
Side Effects
Urgent Side Effects: Seek Medical Help Right Away
While rare, some people may experience severe and potentially life-threatening side effects when taking this medication. If you notice any of the following symptoms, contact your doctor or seek immediate medical attention:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Severe dizziness or fainting
Abnormal heartbeat (fast or slow)
Other Possible Side Effects
As with any medication, you may experience side effects. Although many people do not have any side effects or only have mild ones, it is essential to discuss any concerns with your doctor. If you experience any of the following side effects or any other unusual symptoms that bother you or do not go away, contact your doctor:
Headaches, which may occur when you start taking this medication. In most cases, this side effect improves over time. Do not adjust your dosage without consulting your doctor. Instead, discuss ways to manage this side effect with your healthcare provider.
Reporting Side Effects
This list is not exhaustive, and you may experience other side effects. If you have questions or concerns, contact your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch. Your doctor can provide medical advice and guidance on managing side effects.
While rare, some people may experience severe and potentially life-threatening side effects when taking this medication. If you notice any of the following symptoms, contact your doctor or seek immediate medical attention:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Severe dizziness or fainting
Abnormal heartbeat (fast or slow)
Other Possible Side Effects
As with any medication, you may experience side effects. Although many people do not have any side effects or only have mild ones, it is essential to discuss any concerns with your doctor. If you experience any of the following side effects or any other unusual symptoms that bother you or do not go away, contact your doctor:
Headaches, which may occur when you start taking this medication. In most cases, this side effect improves over time. Do not adjust your dosage without consulting your doctor. Instead, discuss ways to manage this side effect with your healthcare provider.
Reporting Side Effects
This list is not exhaustive, and you may experience other side effects. If you have questions or concerns, contact your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch. Your doctor can provide medical advice and guidance on managing side effects.
Seek Immediate Medical Attention If You Experience:
- Severe dizziness or lightheadedness, especially when standing up.
- Fainting (syncope).
- Blurred vision.
- Unusual sweating.
- Persistent or worsening headache that is severe.
- Signs of very low blood pressure (e.g., extreme fatigue, confusion).
Before Using This Medicine
Before Taking This Medication: Important Information to Share with Your Doctor
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the symptoms you experienced.
Certain health conditions, including:
+ Heart failure (a weak heart)
+ A recent heart attack
If you are currently taking any of the following medications:
+ Avanafil
+ Riociguat
+ Sildenafil
+ Tadalafil
+ Vardenafil
Please note that this is not an exhaustive list of all potential interactions. To ensure your safety, it is crucial to disclose all of your:
Prescription and over-the-counter (OTC) medications
Natural products
Vitamins
* Health problems
Your doctor and pharmacist need this information to determine whether it is safe for you to take this medication in conjunction with your other medications and health conditions. Never start, stop, or adjust the dosage of any medication without first consulting your doctor.
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the symptoms you experienced.
Certain health conditions, including:
+ Heart failure (a weak heart)
+ A recent heart attack
If you are currently taking any of the following medications:
+ Avanafil
+ Riociguat
+ Sildenafil
+ Tadalafil
+ Vardenafil
Please note that this is not an exhaustive list of all potential interactions. To ensure your safety, it is crucial to disclose all of your:
Prescription and over-the-counter (OTC) medications
Natural products
Vitamins
* Health problems
Your doctor and pharmacist need this information to determine whether it is safe for you to take this medication in conjunction with your other medications and health conditions. Never start, stop, or adjust the dosage of any medication without first consulting your doctor.
Precautions & Cautions
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication. If you are using this drug to manage chest pain, note that it is designed to prevent or reduce the frequency of chest pain attacks, but it will not provide immediate relief for sudden chest pain. If you experience new or worsening chest pain or pressure, seek emergency medical attention immediately.
To ensure your safety, avoid driving and other activities that require alertness until you understand how this medication affects you. To minimize the risk of dizziness or fainting, stand up slowly after sitting or lying down, and exercise caution when climbing stairs. Monitor your blood pressure and heart rate as directed by your doctor.
Before consuming alcohol, discuss the potential risks and benefits with your doctor. Long-term, uninterrupted use of this medication can lead to tolerance, reducing its effectiveness. To avoid this, your doctor may recommend a daily "nitrate-free" period. If you notice the medication is no longer working as well, consult your doctor; do not exceed the prescribed dosage.
If you are pregnant, planning to become pregnant, or breastfeeding, inform your doctor to discuss the potential benefits and risks of this medication to both you and your baby.
To ensure your safety, avoid driving and other activities that require alertness until you understand how this medication affects you. To minimize the risk of dizziness or fainting, stand up slowly after sitting or lying down, and exercise caution when climbing stairs. Monitor your blood pressure and heart rate as directed by your doctor.
Before consuming alcohol, discuss the potential risks and benefits with your doctor. Long-term, uninterrupted use of this medication can lead to tolerance, reducing its effectiveness. To avoid this, your doctor may recommend a daily "nitrate-free" period. If you notice the medication is no longer working as well, consult your doctor; do not exceed the prescribed dosage.
If you are pregnant, planning to become pregnant, or breastfeeding, inform your doctor to discuss the potential benefits and risks of this medication to both you and your baby.
Overdose Information
Overdose Symptoms:
- Severe hypotension (very low blood pressure)
- Persistent throbbing headache
- Palpitations
- Visual disturbances
- Flushing
- Sweating
- Nausea and vomiting
- Dizziness and syncope
- Methemoglobinemia (bluish discoloration of skin and lips, shortness of breath, fatigue - rare but serious)
What to Do:
Seek immediate medical attention or call emergency services. For suspected overdose, call a poison control center at 1-800-222-1222.
Drug Interactions
Contraindicated Interactions
- Phosphodiesterase-5 (PDE5) inhibitors (e.g., sildenafil, tadalafil, vardenafil, avanafil) - concurrent use can cause profound hypotension, myocardial infarction, and death.
- Riociguat (soluble guanylate cyclase stimulator) - concurrent use can cause profound hypotension.
Major Interactions
- Other vasodilators (e.g., alpha-blockers, calcium channel blockers, other antihypertensives) - additive hypotensive effects.
- Alcohol - enhances hypotensive effects.
Moderate Interactions
- Tricyclic antidepressants - may reduce hypotensive effects of nitrates.
- Dihydroergotamine - may antagonize the antianginal effect of nitrates and increase risk of angina.
Minor Interactions
- Aspirin - may increase nitrate levels and effects.
Monitoring
Baseline Monitoring
Blood Pressure (BP)
Rationale: To establish baseline and assess for hypotension.
Timing: Prior to initiation of therapy.
Heart Rate (HR)
Rationale: To establish baseline and assess for reflex tachycardia.
Timing: Prior to initiation of therapy.
Routine Monitoring
Blood Pressure (BP)
Frequency: Regularly, especially during dose titration and if symptoms of hypotension occur.
Target: Maintain within patient's normal range, avoiding symptomatic hypotension.
Action Threshold: Systolic BP < 90 mmHg or symptomatic hypotension (dizziness, syncope).
Heart Rate (HR)
Frequency: Regularly, especially during dose titration.
Target: Maintain within patient's normal range, avoiding significant tachycardia.
Action Threshold: Significant reflex tachycardia (>100 bpm or symptomatic).
Angina Symptoms (frequency, severity, duration)
Frequency: Continuously by patient report.
Target: Reduction in angina episodes.
Action Threshold: Increased frequency or severity of angina, indicating inadequate control or development of tolerance.
Headache (severity, frequency)
Frequency: Continuously by patient report.
Target: Mild to moderate, often indicates drug efficacy.
Action Threshold: Severe or persistent headache requiring intervention.
Symptom Monitoring
- Headache (common, often indicates efficacy)
- Dizziness or lightheadedness (especially upon standing)
- Flushing of face and neck
- Nausea
- Weakness
- Palpitations
- Blurred vision (rare)
- Syncope (fainting)
Special Patient Groups
Pregnancy
Category C. Animal studies have shown adverse effects, but there are no adequate and well-controlled studies in pregnant women. Use only if the potential benefit justifies the potential risk to the fetus.
Trimester-Specific Risks:
First Trimester:
Potential for fetal harm based on animal data; use with caution.
Second Trimester:
Potential for fetal harm based on animal data; use with caution.
Third Trimester:
Potential for fetal harm based on animal data; use with caution.
Lactation
It is not known whether isosorbide dinitrate is excreted in human milk. Caution should be exercised when administered to a nursing mother.
Infant Risk:
Not available
Pediatric Use
Safety and effectiveness in pediatric patients have not been established. Use is generally not recommended.
Geriatric Use
Elderly patients may be more susceptible to the hypotensive effects of nitrates. Lower initial doses and careful titration are recommended. Increased risk of falls due to orthostatic hypotension.
Clinical Information
Clinical Pearls
- Nitrate tolerance is a significant issue with chronic use; a daily nitrate-free interval (typically 10-14 hours) is crucial to maintain efficacy and prevent tolerance.
- Headache is a common side effect, especially at the beginning of therapy, and often indicates the drug is working. It usually subsides with continued use.
- Patients should be advised to sit or lie down if they experience dizziness or lightheadedness.
- Isosorbide dinitrate is used for prophylaxis of angina, not for acute angina attacks (sublingual nitroglycerin is preferred for acute relief).
- Educate patients about the absolute contraindication with PDE5 inhibitors (e.g., Viagra, Cialis) due to the risk of severe, life-threatening hypotension.
Alternative Therapies
- Beta-blockers (e.g., metoprolol, atenolol) for angina prophylaxis.
- Calcium channel blockers (e.g., amlodipine, diltiazem, verapamil) for angina prophylaxis.
- Ranolazine (Ranexa) for chronic angina.
- Long-acting nitrates (e.g., isosorbide mononitrate) which have simpler dosing due to longer half-life.
Cost & Coverage
Average Cost:
$10 - $50 per 30 tablets (generic 40mg)
Generic Available:
Yes
Insurance Coverage:
Tier 1 or Tier 2 (generic)
General Drug Facts
If your symptoms or health issues persist or worsen, it's essential to contact your doctor for further guidance. To ensure your safety, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so be sure to check with your pharmacist for more information. If you have any questions or concerns about this medication, don't hesitate to reach out to your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek emergency medical attention. When seeking help, be prepared to provide details about the overdose, including the medication taken, the amount, and the time it occurred.