Prasugrel

Drug Information: Prasugrel

Prasugrel is a thienopyridine class antiplatelet agent used to reduce the risk of thrombotic cardiovascular events such as stent thrombosis in patients with acute coronary syndromes (ACS) who are managed with percutaneous coronary intervention (PCI). It works by irreversibly inhibiting the P2Y12 receptor on platelets, preventing ADP-mediated platelet activation and aggregation. Unlike clopidogrel, prasugrel does not require extensive metabolic activation, leading to more consistent and potent platelet inhibition.

Category

Drugs for ACS

Mechanism of Action

Prasugrel is a P2Y12 receptor inhibitor, meaning it blocks the action of adenosine diphosphate (ADP) on its platelet receptor P2Y12. ADP is a key mediator of platelet aggregation. When ADP binds to the P2Y12 receptor on platelets, it initiates a signaling cascade that leads to the activation of the glycoprotein IIb/IIIa complex, which is essential for platelets to bind to fibrinogen and aggregate. Prasugrel is a prodrug that needs to be metabolized into its active form to exert its antiplatelet effect. After oral administration, prasugrel is rapidly converted to its active metabolite, R-138727, primarily by CYP3A4 and CYP2B6. The active metabolite then forms an irreversible and selective complex with the P2Y12 receptor. This irreversible binding prevents ADP from binding to the receptor, thereby inhibiting platelet activation and aggregation for the lifespan of the platelet (7-10 days). Because the inhibition is irreversible, platelet function will only return when new platelets are produced by the bone marrow.

Clinical Uses

Prasugrel is primarily indicated to reduce the rate of thrombotic cardiovascular events (including stent thrombosis) in patients with acute coronary syndrome (ACS) who are planned for percutaneous coronary intervention (PCI). This includes patients with unstable angina (UA), non-ST-segment elevation myocardial infarction (NSTEMI), and ST-segment elevation myocardial infarction (STEMI). It is typically used in conjunction with aspirin and is administered after PCI to prevent blood clots from forming within the newly placed stent. Its more rapid and potent platelet inhibition compared to clopidogrel makes it a preferred option in many clinical scenarios, particularly when rapid and consistent antiplatelet effects are needed.

Dosage

Adult: Typically, prasugrel is administered as a 60 mg oral loading dose, followed by a 10 mg daily oral maintenance dose. For patients weighing less than 60 kg, a maintenance dose of 5 mg daily may be considered.

Pediatric: The safety and effectiveness of prasugrel in pediatric patients have not been established. It is generally not recommended for use in children.

Indications

* Acute Coronary Syndrome (ACS) in patients undergoing Percutaneous Coronary Intervention (PCI)
* Unstable Angina (UA)
* Non-ST-Segment Elevation Myocardial Infarction (NSTEMI)
* ST-Segment Elevation Myocardial Infarction (STEMI)

Contraindications

* History of prior stroke or transient ischemic attack (TIA)
* Active pathological bleeding, such as peptic ulcer or intracranial hemorrhage
* Hypersensitivity to prasugrel or any of its components
* Severe hepatic impairment
* It’s generally avoided in patients ≥75 years old due to increased bleeding risk unless deemed essential.

FAQ

Q: What is Prasugrel used for?

A: Prasugrel is used to prevent blood clots in patients with acute coronary syndrome (ACS) who are undergoing percutaneous coronary intervention (PCI).

Q: How does Prasugrel work?

A: Prasugrel blocks the P2Y12 receptor on platelets, preventing ADP from activating them and causing them to clump together.

Q: What are the common side effects of Prasugrel?

A: The most common side effect is bleeding. Other possible side effects include bruising, nosebleeds, and gastrointestinal bleeding.

Q: Can I take Prasugrel if I have a history of stroke?

A: No, Prasugrel is contraindicated in patients with a history of stroke or TIA due to the increased risk of intracranial hemorrhage.

Q: What should I do if I need surgery while taking Prasugrel?

A: Prasugrel usually needs to be stopped several days before surgery to reduce the risk of bleeding. Consult your doctor for specific instructions.

Q: Are there any drug interactions with Prasugrel?

A: Yes, Prasugrel can interact with other medications that increase the risk of bleeding, such as NSAIDs, warfarin, and other antiplatelet agents.

Q: What should I do if I miss a dose of Prasugrel?

A: Take the missed dose as soon as you remember. However, if it is almost time for your next dose, skip the missed dose and continue with your regular dosing schedule. Do not double the dose to catch up.

Q: Is Prasugrel better than clopidogrel?

A: In some studies, Prasugrel has shown to be more effective than clopidogrel at reducing the risk of thrombotic events in patients with ACS undergoing PCI. However, it is also associated with a higher risk of bleeding. The choice between the two depends on the individual patient’s risk factors and clinical situation.