Ticagrelor and Aspirin Loading Doses in Posterior Circulation Stroke
For patients with posterior circulation stroke, the recommended loading dose is 180 mg of ticagrelor and 162-325 mg of aspirin, followed by maintenance doses of 90 mg twice daily for ticagrelor and 81 mg daily for aspirin. 1
Loading Dose Recommendations
Ticagrelor Loading Dose
- Loading dose of 180 mg orally as early as possible or at the time of intervention 1
- Ticagrelor has a rapid onset of action, achieving significant platelet inhibition within 30 minutes of administration 1
- Peak inhibitory effect is seen approximately 2 hours after the loading dose 1
Aspirin Loading Dose
- Loading dose of 162-325 mg orally before procedure or intervention 1
- For patients with impaired swallowing, rectal aspirin 325 mg is a reasonable alternative 1
Maintenance Dose Regimen
Ticagrelor Maintenance
- 90 mg twice daily following the loading dose 1
- When used with ticagrelor, the preferred maintenance dose of aspirin is 81 mg daily 1
- Important consideration: Twice-daily dosing may affect patient compliance 1
Duration of Therapy
- For minor ischemic stroke (NIHSS ≤ 3) or high-risk TIA (ABCD2 ≥ 4), dual antiplatelet therapy (DAPT) with ticagrelor and aspirin is recommended for 30 days 1
- For patients receiving drug-eluting stents, DAPT should continue for at least 12 months 1
Evidence for Posterior Circulation Stroke
While specific guidelines for posterior circulation stroke are limited, evidence supports the use of dual antiplatelet therapy in acute ischemic stroke:
- The THALES trial demonstrated that ticagrelor plus aspirin reduced the risk of stroke or death within 30 days compared to aspirin alone in patients with mild-to-moderate acute non-cardioembolic ischemic stroke 2
- In patients with atherosclerotic stenosis, ticagrelor was superior to aspirin at preventing stroke, myocardial infarction, or death at 90 days 3
Safety Considerations
- Bleeding risk: Severe bleeding occurred in 0.5% of patients on ticagrelor-aspirin compared to 0.1% on aspirin alone in the THALES trial 2
- Ticagrelor should be avoided in patients with prior history of intracranial hemorrhage 1
- Caution is advised when considering ticagrelor in patients with prior stroke or TIA due to possible increased risk of intracranial bleeding 1
- Discontinue ticagrelor at least 5 days before planned surgery 1
Clinical Pearls
- Always rule out intracranial hemorrhage on neuroimaging before initiating antiplatelet therapy 1
- Initiate therapy as early as possible, ideally within 24 hours of symptom onset for maximum benefit 1, 2
- For patients already receiving clopidogrel, a loading dose of ticagrelor should still be administered when switching to ticagrelor 1
- Ticagrelor does not require hepatic conversion to an active metabolite, providing more consistent platelet inhibition compared to clopidogrel 1