From the Guidelines
When PDE4 inhibitors fail to treat erectile dysfunction, consider switching to PDE5 inhibitors like sildenafil (Viagra), tadalafil (Cialis), or vardenafil (Levitra), which are the first-line medications for ED, as recommended by the American Society of Clinical Oncology 1. PDE4 inhibitors such as roflumilast are primarily used for respiratory conditions and are not FDA-approved for erectile dysfunction. If you've been using a PDE4 inhibitor for ED without success, consult your healthcare provider about trying a PDE5 inhibitor starting with standard doses: sildenafil 50mg taken 1 hour before sexual activity, tadalafil 10mg (as needed) or 5mg (daily), or vardenafil 10mg. Some key points to consider when switching to PDE5 inhibitors include:
- Evaluating whether the trial of PDE5 inhibition was adequate, as failure to respond may be due to one or more potentially modifiable factors such as hormonal abnormalities, food or drug interactions, timing and frequency of dosing, lack of adequate sexual stimulation, heavy alcohol use, and the patient’s relationship with his partner 1.
- Re-education and counseling, which includes information on patient and partner expectations, proper drug administration, and titration to maximum dosing, as evidence has shown that sildenafil therapy becomes successful in some men who were not previously responders 1.
- If PDE5 inhibitors also fail, your doctor might recommend second-line treatments like vacuum erection devices, intracavernosal injections (such as alprostadil), or urethral suppositories, as suggested by the American Urological Association 1. Underlying conditions like diabetes, hypertension, or psychological factors should also be addressed as they may contribute to treatment resistance. It is also worth noting that there may be some benefit to initiating the use of any of the above interventions earlier after cancer treatment rather than later, as suggested by the American Society of Clinical Oncology 1.
From the Research
Failure of PDE4i in Erectile Dysfunction
- There are no research papers to assist in answering this question as the provided studies focus on PDE5 inhibitors, not PDE4 inhibitors, in the context of erectile dysfunction 2, 3, 4, 5.
- However, one study discusses PDE4 inhibitors in general, but not specifically in the context of erectile dysfunction, mentioning that they are being developed for lung, skin, and severe neurological diseases 6.
- The studies on PDE5 inhibitors suggest that they are effective and well-tolerated for the treatment of erectile dysfunction, with varying degrees of efficacy and safety profiles among different PDE5 inhibitors 2, 3, 4, 5.