Effective treatment of erectile dysfunction with vardenafil

1-Aryl-3-(4-pyridine-2-ylpiperazin-1-yl)propan-1-one Oximes as Potent Dopamine D4 Receptor Agonists for the Treatment of Erectile Dysfunction

A new series of dopamine D4 receptor agonists, 1-aryl-3-(4-pyridinepiperazin-1-yl)propanone oximes, was designed through the modification of known dopamine D4 receptor agonist PD 168077. Replacement of the amide group with a methylene-oxime moiety produced compounds with improved stability and efficacy. Structure-activity relationsips (SAR) of the aromatic ring linked to the N-4-piperazine ring confirmed the superiority of 2-pyridine as a core for D4 agonist activity. A two-methylene linker between the oxime group and the N-1-piperazine ring displayed the best profile. New dopamine D4 receptor agonists, exemplified by (E)-1-(4-chlorophenyl)-3-(4-pyridin-2-ylpiperazin-1-yl)propan-1-one O-methyloxime (59a) and (E)-1-(3-chloro-4-fluorophenyl)-3-(4-pyridin-2-ylpiperazin-1-yl)propan-1-one O-methyloxime (64a), exhibited favorable pharmacokinetic profiles and showed oral bioavailability in rat and dog. Subsequent evaluation of 59a in the rat penile erection model revealed in vivo activity, comparable in efficacy to apomorphine. Our results suggest that the oximes provide a novel structural linker for 4-arylpiperazine-based D4 agonists, possessing leadlike quality and with potential to develop a new class of potent and selective dopamine D4 receptor agonists.

Safety and Tolerability of Oral Erectile Dysfunction Treatments in the Elderly

Erectile dysfunction (ED) is a common medical condition that affects the sexual life of millions of men worldwide. It is generally accepted that sexual function tends to decline with aging, which is often associated with a higher prevalence of sexual problems, including ED and loss of libido. As the mean age of men seeking medical help for sexual dysfunction continues to increase, it is important to assess the safety and tolerability of currently available medical treatments in elderly men, who often share other co-morbidities that should be carefully evaluated when any type of ED therapy is considered. With this aim in mind, a MEDLINE search was conducted from 1 January 1998 to 31 May 2004 to identify studies assessing the efficacy, safety and tolerability of treatments for ED in the elderly. Particular care was taken to assess the cardiovascular safety of oral drugs for ED in this subset of patients, who often have multiple cardiovascular risk factors which contribute to a complicated clinical scenario. The most important conclusion of the paper is that the high efficacy, reliability, safety and tolerability of oral ED treatments makes them appropriate first-line therapies for elderly patients with ED.

Recreational use of sildenafil by HIV-positive and -negative homosexual/bisexual males

OBJECTIVE

To conduct an epidemiologic review of sildenafil in homosexual and bisexual males focusing on concurrent use with club drugs and/or antiretroviral medications.

DATA SOURCES

A search of MEDLINE was conducted (1966-September 2003), and an extensive manual review of journals was performed using the key search terms club drugs, sildenafil, antiretrovirals, and HIV.

STUDY SELECTION AND DATA EXTRACTION

All articles identified from the data sources were evaluated and information deemed relevant was included.

DATA SYNTHESIS

Several epidemiologic studies have reported that sildenafil is abused in a recreational fashion, typically with agents commonly known to be "club drugs." In this setting, sildenafil may reverse the impotence-inducing effects of the club drugs and restore sexual capabilities. Many implications of both recreational and nonrecreational use of sildenafil exist in relation to HIV disease. Concern has been raised regarding the potential effects on high-risk sexual practices. Also, several researchers have documented interactions between sildenafil and various club drugs, as well as with antiretrovirals intended for HIV disease.

CONCLUSIONS

Serious concerns exist regarding the concurrent use of sildenafil with antiretrovirals and/or club drugs. Clinicians prescribing sildenafil to patients receiving protease inhibitor-containing antiretroviral regimens should be aware of the potential for reduced sildenafil metabolism with resultant adverse effects. Additionally, untoward effects may also occur when sildenafil is used concurrently with various club drugs including amyl and butyl nitrites ("poppers").