SulfonesPurinesPiperazinesPhosphodiesterase 5 InhibitorsPhosphodiesterase InhibitorsVasodilator AgentsErectile Dysfunction3',5'-Cyclic-GMP PhosphodiesterasesCyclic Nucleotide Phosphodiesterases, Type 5HypopituitarismHuman Growth HormoneDrug IndustryPenile ErectionPyrazolesCyclic GMPDatabases, FactualHomosexuality, MaleDouble-Blind MethodMethamphetamineTreatment OutcomeGeorgiaHypertension, PulmonaryCarbolinesImpotence, VasculogenicUnsafe SexPenisSexual BehaviorRisk-TakingPhosphoric Diester HydrolasesPyrimidinonesAdministration, OralTriazinesPulmonary Artery