Comparative Efficacy of Phosphodiesterase Type 5 Inhibitors

Mechanism and Efficacy

High-quality evidence indicates that phosphodiesterase type 5 (PDE5) inhibitors significantly improve erections (73-88% improvement) compared with placebo (26-32%) 1, 2

For sildenafil, improvement in erectile function is related to higher dose (50 mg vs. 25 mg), though there appears to be less additional benefit when increasing from 50 mg to 100 mg 3, 1

The most common adverse effects for PDE5 inhibitors include headache, flushing, rhinitis, and dyspepsia 4
Less common adverse effects include visual disturbances, myalgia, nausea, diarrhea, vomiting, dizziness, and chest pain 4
The incidence of serious adverse events is less than 2% for PDE5 inhibitors, with no significant difference compared to placebo 5

PDE5 inhibitors are effective for erectile dysfunction of various etiologies, including diabetes, depression, cardiovascular disease, prostate cancer, and other medical conditions 1, 6
Sildenafil has been shown to be more effective than non-PDE5 inhibitor treatments such as sublingual apomorphine, psychotherapy, and other medications 3
Combination therapy with sildenafil plus other ED therapies (psychotherapy, atorvastatin, etc.) may provide greater improvements than sildenafil alone 4

The American Urological Association recommends that in case of a medical emergency requiring nitrates, at least 24 hours should have passed since the intake of sildenafil 7
The patient should be informed that sexual stimulation is necessary for the medication to work, and factors such as hormonal abnormalities, food or drug interactions, timing and frequency of dosing, lack of adequate sexual stimulation, excessive alcohol consumption, and the patient's relationship with their partner can affect the response to sildenafil 7

The American Urological Association recommends periodic follow-up to evaluate efficacy, side effects, and any significant changes in the patient's health status or medication 7
If the patient does not respond adequately, it should be assessed whether the use was adequate before changing therapy, considering factors that may affect the response 7