Isosorbide Mononitrate

About Isosorbide Mononitrate

Isosorbide mononitrate relaxes blood vessels, mostly veins, which eases the heart’s workload and helps prevent angina from coronary artery disease. The label says it acts too slowly to stop an attack already under way, so it is taken every day for prevention.

Nitrates lose their effect when blood levels stay up around the clock, and higher doses do not overcome this tolerance, so each form has a schedule that avoids it. Immediate-release tablets are usually 20 mg twice a day, seven hours apart, which leaves a nitrate-free gap each day. Extended-release tablets are taken once a day on arising, starting at 30 or 60 mg, and may be raised to 120 mg, rarely 240 mg. Switching between forms is the prescriber’s decision.

Headache is the most common side effect. The label calls it a sign the drug is working, says aspirin or acetaminophen often relieves it, and warns against changing the schedule to avoid it, since protection can be lost too. Light-headedness on standing can occur, more so after alcohol, and even small doses can cause severe low blood pressure. Nitrates can worsen the angina of hypertrophic cardiomyopathy. There is no boxed warning.

It must not be used by anyone allergic to it, or with sildenafil, tadalafil, vardenafil or riociguat, because blood pressure can fall dangerously. MedlinePlus advises talking to your doctor before stopping it.

Taking Isosorbide Mononitrate

How to take it

Immediate-release tablets twice a day, seven hours apart, for most people on waking and seven hours later. Extended-release tablets once a day on arising, swallowed with half a glass of fluid, not chewed or crushed. Keep taking it even if you feel well.

If you miss a dose

Take it as soon as you remember, unless it is almost time for the next dose; then skip the missed dose and continue your regular schedule. Do not take a double dose.

Storage

At room temperature in the original container, tightly closed, away from excess heat and moisture, and out of reach of children.

Interactions to know about

Sildenafil, tadalafil, vardenafil and other phosphodiesterase inhibitors in any form, and riociguat, must not be taken with it. Alcohol and other medicines that widen blood vessels add to its effect, and calcium channel blockers with nitrates have caused marked low blood pressure on standing.

This summarizes the official prescribing information. Your prescriber’s and pharmacist’s instructions, and the leaflet that comes with your medicine, take priority.

Why the cash price for Isosorbide Mononitrate differs from pharmacy to pharmacy

Extended-release tablets have many generic makers and cost pharmacies little, so a quote is mostly the dispensing fee and markup. Immediate-release tablets have fewer makers and sell less often, so their quotes vary more, and some pharmacies must order them.

The label allows a 30 mg dose as half of a scored 60 mg tablet and a 120 mg dose as two 60 mg tablets, and each strength is priced separately. As a long-term medicine, it suits a ninety-day fill.

Ways to pay less for Isosorbide Mononitrate without insurance

• Ask whether isosorbide mononitrate is on the pharmacy’s flat-price generic list.
• Ask for a ninety-day supply once your dose is settled.
• Ask for quotes on your dose in each strength the label allows; your prescriber decides which to write.
• If immediate-release tablets are hard to find, ask your prescriber whether the once-daily form would suit you.
• Upload the prescription to Script Unlock so licensed pharmacies can quote their cash price. You pay the pharmacy directly.

Questions to ask your pharmacist about Isosorbide Mononitrate

1. 1.Which form is this, and when should I take it?
2. 2.What can I take for the headaches?
3. 3.Is it safe with my blood pressure medicines?
4. 4.Which erectile dysfunction or pulmonary hypertension medicines must I avoid?
5. 5.What should I use for an angina attack, since this does not stop one?

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