Participants undergo buccal swab for genetic testing to determine potential medication response to standard of care (SOC) medications. Upon result, participants are randomized (1:1) to aspirin and clopidogrel vs aspirin and ticagrelor (all SOC for this stroke population). Doses are aspirin either 81mg or loading dose 325mg, clopidogrel either 75mg or loading dose 300mg, ticagrelor either 90mg or loading dose 180mg. Loading doses are given once for aspirin, clopidogrel or ticagrelor; aspirin 81mg is taken once a day for the duration of the study; clopidogrel 75mg is once a day for 21 days only, ticagrelor 90mg is twice daily for 21 days. Participants will only receive loading dose of aspirin if not already taken at home. CYP2C19 results only affect decision regarding clopidogrel and ticagrelor but not aspirin. Aspirin is not affected by CYP2C19 mutation and will be given immediately without waiting for CYP2C19 results.

Participants undergo buccal swab for genetic testing to determine potential medication response to standard of care (SOC) medications. Upon result, participants are randomized (1:1) to aspirin and clopidogrel vs aspirin and ticagrelor (all SOC for this stroke population). Doses are aspirin either 81mg or loading dose 325mg, clopidogrel either 75mg or loading dose 300mg, ticagrelor either 90mg or loading dose 180mg. Loading doses are given once for aspirin, clopidogrel or ticagrelor; aspirin 81mg is taken once a day for the duration of the study; clopidogrel 75mg is once a day for 21 days only, ticagrelor 90mg is twice daily for 21 days. Participants will only receive loading dose of aspirin if not already taken at home. CYP2C19 results only affect decision regarding clopidogrel and ticagrelor but not aspirin. Aspirin is not affected by CYP2C19 mutation and will be given immediately without waiting for CYP2C19 results.

CYP2C19 is a gene that encodes an enzyme responsible for metabolizing several medications, including the antiplatelet drugs.

This outcome is to determine the feasibility of receiving CYP2C19 genetic testing results (strata-normal vs. loss-of-function allele) on minor ischemic stroke and high risk TIA inpatients within a 6-hour window to determine drug metabolization for antiplatelet effect to guide standard of care treatment. Inpatients that have been admitted to the hospital, within 66 hours of last known well time, will have buccal swabs collected during hospitalization for the CYP2C19 genetic testing. Results must be received within 6 hours to effectively randomize subjects.

Participants will undergo a visit approximately 90 days following stroke to assess for any new stroke like symptoms and recovery in daily activities via the modified Rankin scale (mRS) Score. The mRS is a widely used tool to assess functional outcome after a stroke or other neurological events, ranging from 0 (no symptoms) to 6 (dead), with higher scores indicating greater disability.