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(094) Synergy Between Orally Administered Phosphodiesterase-type-5-inhibitors and Topically Delivered Nitric-oxide in Eliciting Erectile Responses

K. Davies, M. Tar, A. Draganski

Journal of Sexual Medicine, 2023

Abstract

Phosphodiesterase-type-5-inhibitors (PDE5i) represent first-line FDA-approved oral treatments for erectile dysfunction (ED). However, because their mode of action is dependent on the production of nitric oxide (NO) from nerve endings, patients that suffer neurogenic ED (for example, following the procedures for radical prostatectomy (RP) or resulting from diabetes) are commonly refractory to PDE5i treatment. We recently demonstrated proof-of-principle for increased efficacy of topically applied NO-releasing microparticles (NO-MP) in eliciting an erectile response when used in combination with the orally administered PDE5i, sildenafil. However, there are several other FDA approved PDE5i used to treat ED, which, although acting through the common mechanism of PDE5 inhibition, exhibit several characteristics that potentially could impact clinical and commercial translation of combination therapy.

The goal of the present studies was to determine if other commercially available PDE5i besides sildenafil (avanafil, tadalafil and vardenafil) also act cooperatively when used in combination with NO-MP to elicit an erectile response.

Sprague-Dawley rats underwent bi-lateral transection of the cavernous nerve (CN), as a model of RP, one-week prior to determining erectile response to treatment. We investigated the effect of oral administration of 0.05mg sildenafil/kg, 0.005mg tadalafil/kg, 0.01mg vardenafil/kg and 0.1mg avanafil/kg (approximately equivalent to clinical doses of 2.5mg,…

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