Various potentially inappropriately prescribed medications can exacerbate heart failure (HF) and lead to adverse outcomes. This study examined patterns of prescribing HF-exacerbating medications for Medicare beneficiaries 65 years old and older, between 2003 and 2014, at admission to hospital for HF, at discharge from same and in between. Among 558 individuals, the numbers of HF-exacerbating medications remained the same or increased for 31% of them. Harmful prescribing practices were most strongly associated with small hospital size and patients with diabetes. The authors call for development of strategies to improve prescribing practices for heart failure patients.