BACKGROUND: Maintaining a steady medication supply during a public health crisis is a major health priority. We leveraged a large U.S. pharmacy-claims database to understand the use of evidence-based therapies in heart failure (HF) care during the coronavirus disease-2019 (COVID-19) pandemic. METHODS: We analyzed 27,027,650 individual claims from an all-payer pharmacy-claims database across 56,155 chain, independent and mail-order pharmacies in 14,164 zip codes in 50 states. Prescriptions dispensed (in 2-week intervals) of evidence-based HF therapies in 2020 were indexed to comparable timeframes in 2019. We normalized these year-to-year changes in HF medical therapies relative to those observed with a stable basket of drugs. RESULTS: Fills of losartan, lisinopril, carvedilol, and metoprolol all peaked in the weeks of March 2020 and demonstrated trajectories thereafter that were relatively consistent with the reference set of drugs. Fills of spironolactone (+4%) and eplerenone (+18%) showed modest trends toward increased relative use during 2020. Fills of empagliflozin (+75%), dapagliflozin (+65%) and sacubitril/valsartan (+61%) showed striking longitudinal increases throughout 2020 that deviated substantially from year-to-year trends of the overall basket of drugs. For all 3 therapies, fills of all quantity sizes increased relatively throughout 2020. For both generic and brand-name therapies, prescription fill patterns from mail-order pharmacies increased substantially over expected trends beginning in March 2020 CONCLUSION: Prescription fills of most established generic therapies used in HF care were maintained, whereas those of sacubitril/valsartan and the sodium-glucose cotransporter-2 inhibitors steeply increased during the COVID-19 pandemic. These nationwide pharmacy claims data provide reassurance about therapeutic access, during a public health crisis, to evidence-based medications used in HF care.