We sought to identify factors influencing dose maintenance of intracavernous (IC) injection among patients with ED following radical prostatectomy. A total of 93 patients underwent prostatectomy and received IC treatment for ED, including PGE1 single therapy (n=53) and triple therapy (n=40). In the PGE1-only group, the maintenance dosage was significantly correlated with preoperative sexual function and nerve sparing (NS) (P<0.05). For example, the maintenance dose among patients with no, unilateral and bilateral NS was 10.8 ± 6.6 μg (0.54 ± 0.33 ml), 10.8 ± 3.8 μg (0.54 ± 0.19 ml) and 6.4 ± 4.6 μg (0.32 ± 0.23 ml), respectively. In terms of preoperative sexual function, the maintenance dose among non-ED versus ED patients was 0.38 ± 0.25 ml (7.6 ± 5.0 μg) and 0.59 ± 0.31 ml (11.8 ± 6.2 μg), respectively. No significant correlation was observed between the maintenance dose and NS or preoperative sexual function among the triple-therapy patients or between the maintenance dose and age, body mass index, systemic diseases and initiation of ED treatment among all patients (P>0.05). Thus, maintenance dose of PGE1 therapy could be partly determined by NS status and prior ED of patients.