Aspirin and Extended-Release Dipyridamole

Aspirin and extended-release dipyridamole has one supported use across both listed products.

• Reducing the risk of stroke in people who have had a transient ischemia of the brain (TIA) or a completed ischemic stroke due to thrombosis (a clot).
• This applies to both the Aspirin and Extended-Release Dipyridamole capsule and the Aspirin And Extended-release Dipyridamole extended-release capsule.

This product combines two antiplatelet medicines whose effects add together. Dipyridamole increases adenosine levels around platelets, which makes them less likely to clump. It also affects an enzyme called phosphodiesterase.

Aspirin permanently blocks the platelet enzyme cyclooxygenase. That lowers thromboxane A2, a chemical that drives platelet clumping and blood vessel narrowing.

The usual routine is one capsule by mouth twice a day, morning and evening. Swallow it whole and do not chew it. Food does not matter, so you can take it either way.

• If early headaches are intolerable, your prescriber may switch you briefly to one capsule at bedtime and low-dose aspirin in the morning.
• Return to the usual twice-daily routine as soon as possible, usually within a week.
• Do not swap it for separate aspirin and dipyridamole tablets.

Follow your prescriber and the label for exact directions.

The most common side effects in studies were:

Headache and stomach upset were also common reasons people stopped the medicine. Get medical help for signs of bleeding, severe stomach pain, allergic reactions, or worsening chest pain.

• Bleeding: the risk is higher, including bleeding in the stomach, intestines and brain. Other blood thinners, antiplatelets, NSAIDs and heavy drinking add to it.
• Stomach problems: avoid it with active peptic ulcer disease. Watch for ulcers and bleeding even if you never had stomach symptoms.
• Pregnancy: aspirin can harm a baby, especially in the third trimester.
• Heart and blood pressure: dipyridamole can trigger or worsen chest pain with coronary artery disease and can worsen low blood pressure.
• Kidney and liver: avoid it in severe kidney or severe liver problems. Liver enzyme rises and liver failure have been reported with dipyridamole.

Many medicines can interact with this combination, mostly because of the aspirin.

• Blood thinners, antiplatelets, anagrelide and NSAIDs: higher bleeding risk.
• Adenosine and regadenoson: dipyridamole boosts their heart effects.
• ACE inhibitors, beta blockers and diuretics: aspirin may weaken their effects.
• Cholinesterase inhibitors: dipyridamole may counteract them and worsen myasthenia gravis.
• Methotrexate and acetazolamide: levels may rise to harmful amounts.
• Phenytoin and valproic acid: aspirin changes their blood levels.
• Oral diabetes medicines: low blood sugar may be more likely.
• Probenecid and sulfinpyrazone: aspirin blocks their effect.
• Alcohol: three or more drinks daily raises bleeding risk.

Not a complete list. The label covers the interactions the manufacturer studied or reported, and our own interaction database does not cover every medicine either. Bring your full medication list, including vitamins and herbal products, to your pharmacist.

• Do not use if allergic to any ingredient, to NSAIDs, or if you have asthma with rhinitis and nasal polyps.
• Not recommended for children and teenagers, because of Reye syndrome risk with viral infections.
• Avoid in the third trimester of pregnancy. Tell your doctor if you are or may become pregnant.
• Breastfeeding: small amounts pass into milk, so discuss it with your doctor.
• Avoid in severe kidney or severe liver problems.
• Tell your doctor about peptic ulcer disease, coronary artery disease or low blood pressure.
• Older adults did about as well as younger adults, but some may be more sensitive.

An overdose is likely to show mostly dipyridamole effects, such as warm feeling, flushing, sweating, restlessness, weakness, dizziness, low blood pressure and fast heartbeat. Too much aspirin can cause ringing in the ears and, in severe cases, fever and fluid loss. For a real or suspected overdose, get medical attention or call Poison Control right away.

The blood-thinning effect comes from the added antiplatelet actions of dipyridamole and aspirin. How each medicine affects the other's action on platelets has not been studied.

Dipyridamole levels peak about 2 hours after a dose. Aspirin peaks within about 30 to 60 minutes. A high-fat meal lowers absorption somewhat, but the label says this does not matter clinically. The two medicines do not significantly affect each other's handling in the body.

Dipyridamole is broken down in the liver and leaves mostly through bile into the stool. Aspirin is partly converted to salicylic acid in the liver and gut wall. Dipyridamole levels were about 40% higher in healthy adults over 65.

Store at 20° to 25°C (68° to 77°F); excursions permitted between 15° to 30°C (59° to 86°F) . Protect from excessive moisture.