Orisantin (Dipyridamole, Acetylsalicylic Acid)

Orisantin combines dipyridamole and acetylsalicylic acid to act on platelet aggregation pathways, offering antithrombotic protection in several cardiovascular contexts.

• Secondary prevention of non‑cardioembolic ischemic stroke: reduces the risk of recurrent stroke when used with aspirin.
• Prevention of thromboembolic events after coronary artery bypass graft surgery: helps maintain graft patency.
• Management of patients with prosthetic heart valves: decreases the likelihood of valve‑related clot formation.

• Dipyridamole inhibits phosphodiesterase enzymes, leading to increased intracellular cyclic AMP and cyclic GMP, which suppress platelet activation. Acetylsalicylic acid irreversibly acetylates cyclooxygenase‑1 in platelets, blocking thromboxane A2 synthesis. Together, they provide a synergistic antiplatelet effect by targeting distinct steps in the platelet aggregation cascade, thereby reducing thrombus formation.

Orisantin may cause a range of adverse reactions, from mild to severe.

Common Side Effects

• Headache: mild to moderate intensity.
• Dizziness or light‑headedness.
• Gastrointestinal discomfort: nausea, dyspepsia, or abdominal pain.
• Bleeding gums or easy bruising.
• Rash or mild skin irritation.
• Flushing or warmth sensation.

Serious or Rare Side Effects

• Severe or uncontrolled bleeding, including intracranial hemorrhage.
• Allergic reactions: hives, swelling, or anaphylaxis.
• Thrombocytopenia: markedly reduced platelet count.
• Hepatic dysfunction: elevated liver enzymes.
• Hemorrhagic stroke.
• Severe gastrointestinal ulceration or perforation.

Before initiating Orisantin, clinicians should evaluate patient‑specific risk factors and monitor for potential complications.

• Assess bleeding risk: review history of ulcers, hemorrhage, or coagulopathy.
• Monitor liver function: periodic testing is advised, especially in patients with hepatic disease.
• Avoid in active peptic ulcer disease: the drug can exacerbate gastrointestinal lesions.
• Use caution in renal impairment: dose adjustments may be required.
• Do not combine with other anticoagulants or antiplatelet agents without medical supervision.
• Store at room temperature: keep in the original pack, protect from moisture and direct sunlight.

Orisantin can interact with several medications, altering its efficacy or safety profile.

Major Interactions (Avoid)

• Other anticoagulants (e.g., warfarin, heparin): increased risk of major bleeding.
• Non‑steroidal anti‑inflammatory drugs (NSAIDs) besides aspirin: additive gastrointestinal bleeding risk.
• Selective serotonin reuptake inhibitors (SSRIs): heightened bleeding tendency.
• Clopidogrel: may reduce antiplatelet effectiveness.
• High‑dose corticosteroids: synergistic ulcerogenic effect.

Moderate Interactions (Monitor Closely)

• Antihypertensive agents: dipyridamole may enhance hypotensive effects.
• Methotrexate: potential increase in toxicity.
• Oral contraceptives: may elevate clotting risk.
• Statins: rare reports of increased muscle toxicity.
• Diuretics: monitor electrolyte balance.