What Imdur Is Used For (Common Use)
Imdur is prescribed to prevent angina pectoris in adults with coronary artery disease. By releasing nitric oxide in the smooth muscle of blood vessel walls, it causes vasodilation—especially venous dilation—reducing preload and myocardial oxygen demand. The result is fewer episodes of chest pain during physical exertion or emotional stress. Imdur is formulated for prevention and maintenance, not for immediate relief; patients should always keep a fast-acting nitrate or other clinician-recommended rescue therapy on hand for acute chest pain and seek emergency care for chest pain that does not promptly resolve.
Clinicians may combine Imdur with other anti-anginal therapies, such as beta blockers or calcium channel blockers, when needed. Because tolerance to nitrates can develop, dosing schedules are designed to include a daily nitrate-free interval. Discuss any exercise changes, smoking cessation efforts, and diet strategies with your care team, as lifestyle modifications work synergistically with Imdur to improve angina control and overall cardiovascular health.
Imdur Dosage and Direction
Only your clinician can determine the right dose for you. A common starting dose of extended-release Imdur in adults is 30–60 mg once daily, usually in the morning. Depending on response and tolerability, the dose may be gradually increased, often to 60–120 mg once daily; some patients may require up to 240 mg once daily. Swallow extended-release tablets whole; do not crush, split, or chew them, as this can rapidly release the drug and increase side effects.
Take Imdur consistently at the same time each day. Follow the specific schedule your clinician provides to preserve a nitrate-free interval, which helps reduce tolerance. If headaches occur early in therapy—common with nitrates—speak with your clinician about supportive measures rather than stopping the medication on your own. Never change your dose or dosing schedule without medical guidance.
Precautions Before and During Imdur Treatment
Imdur can cause dizziness, lightheadedness, or fainting, especially when starting therapy or increasing the dose. Standing up slowly, staying hydrated, and avoiding abrupt position changes can reduce these effects. Use caution when driving or operating machinery until you know how you respond. Alcohol can intensify blood pressure–lowering effects and should be limited or avoided.
Tell your clinician about all medical conditions, including low blood pressure, volume depletion, severe anemia, heart failure, hypertrophic cardiomyopathy, a recent heart attack, or a history of migraines. Nitrates can aggravate headaches initially; these typically lessen over time. Report persistent or severe headaches, unusual fatigue, rapid heartbeat, or new/worsening chest pain promptly.
If you are pregnant, planning pregnancy, or breastfeeding, discuss risks and benefits. Human data are limited; your clinician will consider your specific cardiovascular risk profile. Older adults may be more sensitive to hypotensive effects and require careful monitoring. Keep all follow-up appointments to track blood pressure, angina frequency, and overall response.
Contraindications to Imdur
Do not use Imdur if you are allergic to isosorbide mononitrate, isosorbide dinitrate, nitroglycerin, or any component of the formulation. Imdur is contraindicated with phosphodiesterase-5 (PDE-5) inhibitors such as sildenafil, tadalafil, or vardenafil, and with the soluble guanylate cyclase stimulator riociguat; combining these can cause life-threatening hypotension. Avoid use in patients with marked hypotension, acute circulatory failure, or shock.
Severe anemia is a relative contraindication, and nitrates may be inappropriate in patients with significantly elevated intracranial pressure. Your clinician will evaluate your cardiovascular status, blood pressure, and concomitant therapies before prescribing Imdur to ensure it is appropriate and safe.
Possible Side Effects of Imdur
Common side effects include headache, flushing, dizziness, lightheadedness (especially when standing), nausea, and fatigue. These often improve as your body adjusts. Headache is dose-related and a recognized pharmacologic effect of nitrates; talk to your clinician about strategies to manage it without compromising anti-anginal benefits.
Less common effects include low blood pressure, fainting, reflex tachycardia, palpitations, and rash. Seek urgent medical attention if you experience severe or persistent hypotension, syncope, chest pain that does not resolve with rescue medication, shortness of breath, cyanosis, or signs of an allergic reaction (hives, swelling, difficulty breathing). Rarely, high doses or interactions may contribute to methemoglobinemia, presenting with bluish discoloration of skin or lips, fatigue, and shortness of breath—this requires immediate care.
Imdur Drug Interactions
Avoid combining Imdur with PDE-5 inhibitors such as sildenafil (Viagra, Revatio), tadalafil (Cialis, Adcirca), or vardenafil (Levitra, Staxyn), and with riociguat (Adempas). These combinations can precipitate profound, potentially fatal hypotension. If you use a PDE-5 inhibitor for erectile dysfunction or pulmonary hypertension, inform your clinician before starting Imdur. Do not take PDE-5 inhibitors while on nitrates.
Other antihypertensives (beta blockers, calcium channel blockers, alpha blockers, ACE inhibitors, ARBs), diuretics, and alcohol can enhance blood pressure–lowering effects and may increase dizziness or fainting. Your clinician may adjust doses and monitor closely. While some combinations are intentional for angina control, they require supervision.
Be sure to list all prescription and nonprescription drugs, including migraine therapies, over-the-counter cold remedies, herbal supplements, and recreational substances. Do not start or stop medications without professional guidance, as changes can affect angina stability and blood pressure.
Missed Dose Instructions
If you miss a dose of Imdur, take it as soon as you remember unless it is close to the time for your next dose. If it is nearly time for the next dose, skip the missed dose and resume your regular schedule. Do not take two doses at once to make up for a missed tablet. If you frequently forget doses, consider using reminders or a pill organizer and talk with your clinician about adherence strategies that preserve the nitrate-free interval.
Overdose: Signs and What to Do
Symptoms of Imdur overdose can include severe headache, flushing, nausea, vomiting, marked hypotension, fainting, rapid heartbeat, shortness of breath, and in rare cases signs of methemoglobinemia (bluish skin or lips, confusion, fatigue). Overdose is a medical emergency. Call emergency services immediately. While awaiting help, lie down and elevate your legs to promote blood flow to the brain if you feel faint. Do not take additional doses, food, or alcohol. Bring the medication container to the emergency department so clinicians can verify the drug and dose.
How to Store Imdur Properly
Store Imdur at room temperature, away from excessive heat, moisture, and light. Keep tablets in their original, tightly closed container, and do not store in a bathroom where humidity is high. As with all medications, keep out of reach of children and pets. Do not use tablets past the expiration date, and dispose of unused or expired medication properly—ask your pharmacist about take-back programs or FDA-recommended disposal methods.
U.S. Sale and Prescription Policy for Imdur
In the United States, Imdur (isosorbide mononitrate) is a prescription-only medication. By law, pharmacies and hospitals cannot dispense Imdur without a valid prescription from a licensed clinician. Claims that you can buy Imdur without prescription—online or locally—should be treated with skepticism, as they may involve illegal or unsafe sources, counterfeit products, or medications that have not been stored or handled properly.
For safe, lawful access, schedule an appointment with your primary care clinician, cardiologist, or a reputable telehealth service. During the visit, your clinician will confirm your diagnosis, review your medications for interactions (including PDE-5 inhibitors and riociguat), and determine the right dosage and monitoring plan. Use licensed U.S. pharmacies—community or mail-order—and verify accreditation (for example, through state boards of pharmacy) when applicable. Assistance programs, insurance formularies, and discount cards may reduce cost for eligible patients.
If you encounter advertising or third-party sites suggesting no-prescription access, avoid purchasing and consult a healthcare professional. Your safety depends on correct diagnosis, dosing, and ongoing monitoring—cornerstones of responsible, legal access to Imdur in the U.S.
