1. Clinical Overview
Prasugrel is a potent, third-generation thienopyridine antiplatelet agent used to prevent atherothrombotic events in patients with Acute Coronary Syndrome (ACS) undergoing Percutaneous Coronary Intervention (PCI). It is an irreversible antagonist of the P2Y12 subtype of the adenosine diphosphate (ADP) receptor on platelets, leading to potent and rapid inhibition of platelet aggregation. In the Indian context, it is a critical component of dual antiplatelet therapy (DAPT), often combined with aspirin, for the management of ACS, particularly in patients with diabetes or those at high risk of stent thrombosis.
| Onset | Duration | Bioavailability |
|---|---|---|
| 30 minutes | 5-10 days (platelet function recovery time) | ≥79% (following hydrolysis to active metabolite) |
2. Mechanism of Action
Prasugrel is a prodrug. After oral administration, it is rapidly metabolized to an active metabolite that irreversibly binds to the P2Y12 subtype of the ADP receptor on the platelet surface. This binding inhibits ADP-mediated activation of the glycoprotein GPIIb/IIIa complex, which is the final common pathway for platelet aggregation. This results in potent, selective, and irreversible inhibition of platelet aggregation for the lifespan of the platelet (7-10 days).
3. Indications & Uses
- Prevention of atherothrombotic events in patients with Acute Coronary Syndrome (Unstable Angina, Non-ST-Elevation Myocardial Infarction, ST-Elevation Myocardial Infarction) undergoing Percutaneous Coronary Intervention (PCI).
- Used as part of Dual Antiplatelet Therapy (DAPT) in combination with low-dose aspirin.
4. Dosage & Administration
Adult Dosage: Loading Dose: 60 mg orally as a single dose. Maintenance Dose: 10 mg orally once daily. For patients with ACS undergoing PCI, initiate dose at time of PCI.
Administration: Can be taken with or without food. Tablet should be swallowed whole with a glass of water. Do not crush or chew. For patients who cannot swallow, the tablet can be crushed and mixed in 50 mL of water immediately before administration. Stir for several minutes and drink immediately. Refill the glass with 50 mL of water, stir, and drink to ensure complete dose.
5. Side Effects
Common side effects may include:
- Epistaxis (nosebleed)
- Minor bleeding (e.g., bruising, skin hematoma, gingival bleeding)
- Headache
- Dizziness
- Hypertension
- Nausea
- Back pain
- Dyspnea
6. Drug Interactions
| Drug | Effect | Severity |
|---|---|---|
| Warfarin, Dabigatran, Rivaroxaban, Apixaban | Increased risk of major and fatal bleeding. | Major |
| NSAIDs (e.g., Ibuprofen, Diclofenac) | Increased risk of gastrointestinal bleeding. | Major |
| Other Antiplatelets (e.g., Clopidogrel, Ticagrelor, Aspirin) | Increased antiplatelet effect and bleeding risk. Aspirin is used therapeutically in DAPT. | Major |
| Proton Pump Inhibitors (e.g., Omeprazole, Pantoprazole) | No clinically significant interaction. Can be co-administered for GI protection. | Minor |
| Strong CYP3A4 Inducers (e.g., Rifampicin, Carbamazepine, Phenytoin) | May decrease exposure to prasugrel's active metabolite, potentially reducing efficacy. | Moderate |
| Strong CYP3A4 Inhibitors (e.g., Ketoconazole, Itraconazole, Clarithromycin) | No significant effect on active metabolite exposure or antiplatelet effect. | Minor |
| Opioids (e.g., Morphine) | May delay and reduce absorption of prasugrel, potentially slowing onset of action. | Moderate |
7. Patient Counselling
- DO take the tablet exactly as prescribed by your cardiologist. Do not stop without consulting your doctor, as this increases heart attack/stroke risk.
- DO inform all your doctors and dentists that you are on prasugrel before any surgery or dental procedure.
- DO use a soft toothbrush and electric razor to minimize bleeding from minor cuts.
- DONT take over-the-counter NSAIDs (like ibuprofen, diclofenac) without consulting your doctor.
- DONT crush or chew the tablet unless instructed for administration via nasogastric tube.
8. Toxicology & Storage
Overdose: Expected manifestation would be bleeding complications ranging from minor bleeding (e.g., epistaxis, ecchymosis) to major, life-threatening hemorrhage (e.g., intracranial, gastrointestinal).
Storage: Store at room temperature (15°C to 30°C). Protect from moisture. Keep in the original blister pack or container. Keep out of reach of children.