Pharmacotherapeutic Follow-up and Pharmacogenetics of CYP2C9 and CYP3A4 in Antihypertensive Therapy: A Pilot Study in a Community Pharmacy.

No pharmacogenetic studies have yet been conducted in community pharmacies, despite pharmacogenetics being an emerging discipline. Pharmacotherapeutic follow-up (PFU) was performed for 6 months in 37 patients receiving antihypertensive treatment, and they were genotyped for variant alleles *2 and *3 in the CYP2C9 gene and *1B in CYP3A4. Systolic blood pressure, cardiovascular risk, and adherence improved with PFU. Most of the interactions between drugs were represented by concurrent administration of statins and calcium channel blockers, which both use CYP3A4 for their metabolism. Heterozygotic patients for the CYP2C9*2 allele showed higher mean heart rate values after PFU than homozygous patients (73.4 ± 10.0 pulse/min vs 66.2 ± 10.6 pulse/min, respectively; P = .048). Carriers of CYP2C9*2 showed a tendency to less frequent negative outcomes associated with medication due to inefficacy than homozygous patients (50% vs 78.9%, respectively; P = .072). Pharmacogenetics and PFU can be used in community pharmacies to carry out a more exhaustive study of medication in hypertensive outpatients.