Mean site-weighted prevalence of exposure (log scale) to a CPIC Level A drug or drug class from 2011–2016. Analgesic includes codeine, oxycodone, tramadol; Selective serotonin reuptake inhibitors (SSRIs) includes citalopram, escitalopram, fluvoxamine, paroxetine; Anesthetic includes desflurane, isoflurane, sevoflurane, succinylcholine; Tricyclic antidepressant includes amitriptyline, nortriptyline; Other includes allopurinol, ivacaftor, rasburicase; Immunosuppressant includes azathioprine, mercaptopurine, tacrolimus, thioguanine; Anti-seizure includes carbamazepine, phenytoin; Chemotherapeutic includes capecitabine, fluorouracil, irinotecan; HIV antivirals includes abacavir, atazanavir; Hepatitis C antivirals includes peginterferon alfa-2a/2b, ribavirin.