In such populations, if aspirin is contraindicated, clopidogrel dose escalation or antiplatelet agents not influenced by CYP2C19 genetic variants, such as ticagrelor and ticlopidine, could be alternative P2Y12 inhibitors for CYP2C19 LOF alleles carriers after ischemic stroke or TIA. This evidence concerns the gene CYP2C19 and transient ischemic attack.