A therapeutic taxonomy of treatments for erectile dysfunction: an evolutionary imperative

Abstract

Aim of the study: A functional classi®cation of treatments for erectile dysfunction is important but none exists at present. Advances in the understanding of the mechanisms of drug action and of the mechanisms of penile erection suggest that there is now a rational basis for a therapeutic classi®cation, with the expectation that a logical diagnostic classi®cation will follow.Methods: The currently available treatments for erectile function and the known relevant basic science were reviewed and assessed. From this, and analysis of classi®cation systems in other ®elds, a classi®cation was proposed and evaluated with respect to existing treatments.Results: The treatments for erectile dysfunction were classi®ed into ®ve major classes by their mode of action: (I) Central Initiators, (II) Peripheral Initiators, (III) Central Conditioners, (IV) Peripheral Conditioners and (V) Other. Drugs in these classes are further subdivided by the routes of administration and the mechanisms of speci®city.Conclusions: It is possible to analyze all known treatments using this classi®cation. The principles of this scheme should be suf®ciently clear as to enable knowledgeable specialists to arrive at similar conclusions about a drug. The classi®cation proposed is general enough such that most new drugs should fall within a class. However, it should be modi®ed if necessary, if new therapeutic agents can not be appropriately classi®ed. It is our conclusion that with such endeavours the speciality itself and national regulatory bodies will ®nd it easier to de®ne and control how to apply new drugs, how to evaluate new drugs, and how to establish reasonable equivalences among agents and in whom these drugs and devices should be used.

The value of sildenafil as mode of stimulation in pharmaco-penile duplex ultrasonography

“…Moreover, visual erotic stimulation (VES) was added to initiate erection. 4 Using an ATL HDI 1 5000 CV Duplex scanner, PPDU was performed as described by Meuleman et al 5 To assess arterial response we used peak¯ow velocity (PSV) and acceleration time (AT). To assess veno-occlusive response resistance index (RI) was calculated.…”

Involvement of L-arginine/nitric oxide pathway at the paraventricular nucleus of hypothalamus in central neural regulation of penile erection in the rat

“…24 Heaton et al have proposed a therapeutic taxonomy and classified the treatments for erectile dysfunction into five classes: central initiator, peripheral initiator, central conditioner, peripheral conditioner, and other. 36 The results of this study showed that L-arginine may initiate penile erection through its action on a site (PVN) of CNS which may provide an academic basis to classify L-arginine as a central initiator. Accordingly, the implication of this experimental study was that L-arginine may be used clinically to induce penile erection through its action in the CNS.…”

Effects of oral phentolamine, taken before sleep, on nocturnal erectile activity: a double-blind, placebo-controlled, crossover study

“…20 Therefore, phentolamine should be considered as a conditioner (enhancer) of the erotic and=or nocturnal erections, rather than an initiator, improving the rigidity and duration of the erectile episodes. 21 Based on the results of our study, the question raised is can the available conditioners of the erectile process prevent ED, when administered before sleep for a long time period? Future studies will give the answer.…”