The purpose of this study is to determine whether the implementation of pre-emptive pharmacogenomic (PGx) testing of a panel of clinically relevant PGx markers, to guide the dose and drug selection for 39 commonly prescribed drugs, will result in an overall reduction in the number of clinically relevant drug-genotype associated ADRs which are causally related to the initial drug of inclusion (referred to as 'index drug').

Inclusion Criteria:

• Inclusion Criteria:

In order to be eligible to participate in this study, a subject must meet all of the following criteria:

1. Subject must be ≥ 18 years old
2. Subject must receive a 1st prescription (meaning no known prescription for this drug in the preceding 12 months) for a drug included in Table 1, which is prescribed to them in routine primary care.
3. Subject is able and willing to take part and willing to be followed up on for 48 weeks
4. Subject is able to donate saliva
5. Subject has signed informed consent
6. Subject meets requirement for computer access implying computer literacy as measured by active use of the patient portal or their email

Exclusion Criteria:

1. For the investigational arm only: Previous (direct-to-consumer, or clinical) pharmacogenomic testing that includes any of the genes included in the Focused Pharmacogenomics Panel
2. Pregnant or lactating (to be verbally confirmed with the patient)
3. Life expectancy estimated to be less than three months as determined by patient receiving hospice care
4. Duration of index drug total treatment length is planned to be less than seven consecutive days.
5. Current inpatients
6. Unable to consent to the study
7. Unwilling to take part
8. Subject has no permanent address
9. Subject has no current primary care provider
10. Subject is, in the opinion of the study coordinator after discussion with participating clinician/pharmacist/investigator, not suitable to participate in the study
11. Patient has a diagnosis of stage 4 or 5 chronic kidney disease (CKD) or is receiving dialysis
12. Patients with advanced liver failure (stage Child-Pugh C) or a diagnosis of liver cirrhosis
13. History of a liver transplant or an allogeneic hematopoietic stem cell transplant
14. DNA sample collected that requires retesting in the event that DNA collected was not sufficient for testing as determined by the laboratory

Deidentified individual data that supports the results will be shared beginniing 9 to 36 months following publication provided the investigator who proposes the use of the data has approval from an Institutional Review Board (IRB), Independent Ethics Committee (IEC), or Research Ethics Board (REB), as applicable, and executes a data sharing use /sharing agreement with Mayo Clinic and the PI.