SulfonesPurinesPiperazinesPhosphodiesterase 5 InhibitorsPhosphodiesterase InhibitorsErectile Dysfunction3',5'-Cyclic-GMP PhosphodiesterasesCyclic Nucleotide Phosphodiesterases, Type 5CanadaVasodilator AgentsPenile ErectionContraceptives, OralCyclic GMPContraceptives, PostcoitalContraceptives, Oral, CombinedContraceptives, Oral, HormonalHomosexuality, MaleMethamphetamineContraception, PostcoitalGeorgiaHypertension, PulmonaryContraception BehaviorContraceptive Agents, FemaleContraceptionDrug PackagingEthinyl EstradiolMedication AdherenceContraceptive Devices, FemaleDesogestrelCarbolinesContraceptives, Oral, SyntheticAdministration, OralImpotence, VasculogenicUnsafe SexSexual BehaviorPenisDrugs, Chinese HerbalContraceptive DevicesPatient ComplianceContraceptive AgentsTreatment OutcomeDouble-Blind MethodRisk-Taking