Loading Doses for Aspirin, Ticagrelor, and Prasugrel in ACS in the UK
For patients with Acute Coronary Syndrome (ACS) in the UK, the recommended loading doses are: aspirin 150-300 mg (non-enteric coated), ticagrelor 180 mg, and prasugrel 60 mg. 1
Aspirin Loading Dose
- Non-enteric coated, chewable aspirin at a loading dose of 150-300 mg should be given to all patients with ACS without contraindications as soon as possible after presentation 1
- This initial high dose ensures rapid and complete platelet inhibition during the acute thrombotic phase 2
- For patients already on daily aspirin therapy before PCI, they should still receive 150-300 mg non-enteric coated aspirin before the procedure 1
Ticagrelor Loading Dose
- Ticagrelor loading dose is 180 mg, followed by 90 mg twice daily maintenance dose 1
- Ticagrelor can be administered regardless of prior P2Y12 inhibitor regimen 1
- For pre-treatment in patients with NSTE-ACS undergoing invasive management, ticagrelor administration (180 mg loading dose) should be considered as soon as the diagnosis is established 1
Prasugrel Loading Dose
- Prasugrel loading dose is 60 mg, followed by 10 mg daily maintenance dose 1
- Prasugrel should only be administered in P2Y12-inhibitor naïve patients who proceed to PCI 1
- Administration of prasugrel in patients in whom coronary anatomy is not known is not recommended 1
Important Clinical Considerations
Contraindications and Cautions
- Prasugrel is contraindicated in patients with previous intracranial hemorrhage, previous ischemic stroke or TIA, or ongoing bleeds 1
- Prasugrel is not recommended for patients ≥75 years of age or with a body weight <60 kg 1
- Prasugrel should not be administered to patients with a prior history of stroke or transient ischemic attack 1
Maintenance Therapy After Loading
- After the loading dose, aspirin should be continued indefinitely at a maintenance dose of 75-100 mg daily 1
- When using ticagrelor, the recommended maintenance dose of aspirin is specifically 81 mg daily 1
- Dual antiplatelet therapy (DAPT) should be continued for 12 months in patients with ACS unless there are contraindications such as excessive bleeding risk 1
P2Y12 Inhibitor Selection
- Ticagrelor is recommended over clopidogrel for patients with NSTE-ACS treated with an early invasive strategy 1
- Prasugrel is recommended over clopidogrel for P2Y12 treatment in patients with NSTE-ACS who undergo PCI and are not at high risk of bleeding complications 1
- Prasugrel appears to be associated with lower rates of myocardial infarction and potentially lower risk of bleeding compared to ticagrelor in some studies 3
Switching Between P2Y12 Inhibitors
- When switching from ticagrelor to clopidogrel, a loading dose of 600 mg of clopidogrel should be administered after ticagrelor is discontinued 4
- When switching from clopidogrel to ticagrelor, a loading dose of 180 mg of ticagrelor is recommended irrespective of timing and loading dose of clopidogrel 1
Bleeding Risk Considerations
- Using radial over femoral access for coronary angiography and PCI is recommended to minimize bleeding risk 1
- A proton pump inhibitor in combination with DAPT is recommended to reduce gastrointestinal bleeding risk 1, 5
- Lower maintenance doses of aspirin (75-100 mg) are associated with reduced bleeding risk without compromising efficacy 1, 6
By following these loading dose recommendations and considering the specific clinical context of each patient, optimal antiplatelet therapy can be provided to patients with ACS in the UK setting.