There is a new emerging concept that Botulinum Toxin Type A may have a potential role in treatment of erectile dysfunction with a longer duration of action. So, the investigators opted to perform this study to compare ICI of Botulinum Toxin Type A versus Trimix for treatment of ED.

Background: Direct Intracavernosal injections of vasoactive agents to treat erectile dysfunction were first described in 1982 using papaverine. Later on many agents have been introduced for ICI. one of most newly introduced ICI agents for treatment of ED is Botulinum Toxin Type A.

Purpose: The aim of this study will to compare the safety, efficacy, tolerability and adverse events s of ICI of BTX-A 100 unit in comparison with ICI Trimix in the treatment of Erectile Dysfunction for PDE5Is non-responders.

Design, Settings, and Participants: This study will be conducted on 124 patients at minimum, complain of erectile dysfunction not responding to different PDE5Is therapy presenting to Urology department and outpatient clinic at Banha University Hospital.

patients will be randomized into 2 equal groups: The treatment group A: will receive a single ICI of BTX-A 100 units . The treatment group B: will receive on-demand ICI of Trimix .

Assessment for all groups will be done by Sexual Health Inventory for men (SHIM), Sexual Encounter Profile questions 2 and 3 (SEP 2 & SEP 3), and the global assessment question (GAQ) based on pre-treatment, 2 weeks, 3 months and every 3 months after treatment.

Inclusion Criteria:

• Age more than 40 years with ED not responding to PDE5Is, non compliant or contraindicated to PDE5Is. A "No" response on Sexual encounter profile questions (SEP 2 & 3)

Exclusion Criteria:

• psychiatric condition Any presence of penile anatomical abnormalities (e.g. penile fibrosis) that would significantly impair erectile function.