PDE5 Inhibitors: Which to Start and When to Sequence

How to cite: Patel DP. “PDE5 Inhibitors: Which to Start and When to Sequence.” Grand Rounds in Urology. November 15, 2025. Accessed Apr 2026. https://grandroundsinurology.com/pde5-inhibitors-which-to-start-and-when-to-sequence/

Summary

Darshan P. Patel, MD, Associate Professor of Urology, University of California, San Diego, San Diego, California, provides a practical, guideline-based framework for initiating and optimizing PDE5 inhibitor therapy, emphasizing patient-centered decision-making and appropriate medication use.

Dr. Patel begins by reviewing the current landscape of FDA-approved PDE5 inhibitors, including sildenafil, tadalafil, vardenafil, and avanafil. He highlights that the American Urological Association guidelines recommend PDE5 inhibitors as first-line therapy but do not favor one agent over another, emphasizing patient preference, cost, dosing flexibility, and tolerability. Pharmacokinetic differences are reviewed, including onset of action, duration, and food interactions.

Common side effect profiles are discussed, with sildenafil and vardenafil more often associated with headache, flushing, and visual changes, while tadalafil is more frequently linked to myalgias and back pain. Avanafil is noted for higher PDE5 selectivity and lower adverse event rates, though its higher cost may limit use. Dr. Patel stresses the importance of matching therapy to patient lifestyle.

Dr. Patel addresses management of the PDE5 inhibitor non-responder, noting that up to half of apparent treatment failures are due to improper use. Optimization steps include dose titration, timing relative to sexual activity, avoidance of high-fat meals when appropriate, adequate sexual stimulation, and sufficient trial duration. Testosterone deficiency is emphasized as an important contributor to poor response and should be evaluated in men with erectile dysfunction.

Sequencing strategies are reviewed for men who remain symptomatic despite optimization, including switching agents, combining daily and on-demand therapy, and escalation to alternative treatments. Beyond PDE5 inhibitors, options such as intracavernosal injection therapy, vacuum erection devices, intraurethral therapy, and penile prosthesis placement are discussed, with prosthesis implantation described as the gold standard for refractory erectile dysfunction.

About the 32nd Annual Perspectives in Urology: Point Counterpoint conference: Presented by Program Chair and Grand Rounds in Urology Editor-in-Chief E. David Crawford, MD, this conference brought together leading experts in urology, medical oncology, and radiation oncology to discuss and debate the latest topics in genitourinary cancers, primarily prostate cancer and bladder cancer. This interactive conference offered topical lectures, pro/con debates, interesting-case presentations, interactive panel discussions, and interactive audience and faculty networking.