Erectile DysfunctionYohimbinePenile ErectionImpotence, VasculogenicPenisSulfonesPhosphodiesterase 5 InhibitorsPenile ProsthesisPurinesPhosphodiesterase InhibitorsCarbolinesPenile ImplantationPiperazinesAdrenergic alpha-AntagonistsPriapismAlprostadilAdrenergic alpha-2 Receptor AntagonistsSexual Dysfunctions, PsychologicalSexual Dysfunction, PhysiologicalPenile IndurationLibidoUrological AgentsReceptors, Adrenergic, alphaCyclic Nucleotide Phosphodiesterases, Type 5ClonidineTriazinesPapaverineErgoloid MesylatesVasodilator AgentsCoitusPrazosinSex CounselingReceptors, Adrenergic, alpha-2PhentolamineAdrenergic alpha-AgonistsEjaculationUrologic Diseases3',5'-Cyclic-GMP PhosphodiesterasesButeaTestosteroneVentricular Dysfunction, LeftHypogonadismInjectionsTreatment OutcomeNorepinephrineVacuumApomorphineIdazoxanUrethraImidazolesSet (Psychology)PrevalenceAdrenergic AntagonistsPremature EjaculationDouble-Blind MethodDioxanesDose-Response Relationship, DrugTribulusRisk FactorsQatarEpimediumProstatectomyPenile DiseasesOrgasmPatient SatisfactionMuscle, SmoothUrination DisordersCarthamusReceptors, AdrenergicRats, Sprague-DawleyCynomoriumQuestionnairesAdrenergic alpha-2 Receptor AgonistsOxymetazolineXylazineSeverity of Illness IndexEndothelium, VascularMen's HealthNitric OxideDisease Models, AnimalLepidiumNitric Oxide Synthase Type IProstatismUrinary IncontinenceCross-Over StudiesElectric StimulationTime FactorsDiabetes ComplicationsBlood PressureCardiovascular DiseasesPanaxEunuchismPlacebos