OBJECTIVES: To evaluate the alpha blockers, 5-alpha reductase inhibitors, PDE-5 inhibitor and antimuscarinic medication use in US patients diagnosed with benign prostatic hyperplasia (BPH), lower urinary tract symptoms (LUTS) and erectile dysfunction (ED). METHODS: Employing a retrospective study design on a large US healthcare claims database (MarketScan), male patients aged 18+ with a diagnosis for BPH, LUTS and/or ED between 1/1/07 and 12/31/09 were identified.  Patients with prostatectomy were excluded. Eligible patients had 24 months of continuous pharmaceutical and medical benefit coverage. Chi-square and Wilcoxon tests were used to make statistical comparisons between cohorts: BPH Only (BPH), ED Only (ED), BPH+ED, BPH+LUTS w/o ED and BPH+LUTS w/ED. RESULTS: There were 308,844 patients that met inclusion criteria, and overall 33%, 15%, 19%, and 6% had a prescription for alpha-adrenergic antagonist, 5-alpha-reductase inhibitor, phosphodiesterase-inhibitor, and antimuscarinic, respectively. Overall, 53% had medication use where 6% received combination therapy, 19% switched therapy and 36% discontinued therapy. BPH patients had higher rates of combination medication use (8% vs. 1%, p<0.0001); switching (8% vs. 7%, p=0.0017) and medical visits (17 vs. 14 mean visits, p<0.0001) than ED patients. However, ED had higher rates of therapy discontinuation (27% vs. 15%, p<0.0001) than BPH and ED.  In addition, BPH+ED had higher switching (15% vs. 8%, p<0.0001), discontinuation (24% vs. 15%, p<0.0001) and medical visits (19 vs. 17 mean visits/yr, p<0.0001) than BPH. Furthermore, BPH+LUTS w/ED had higher switching (24% vs. 18%, p <0.0001), discontinuation (27% vs. 22%, p<0.0001) and incurred more medical visits (25 vs. 23 mean visits/yr, p<0.0001) than BPH+LUTS w/o ED.  CONCLUSIONS: BPH and BPH+LUTS patients with ED had higher switching and discontinuation rates than patients without ED. Thus, patients with comorbid ED may require more extensive pharmacologic management and monitoring, resulting in more medical visits than patients without ED.