SulfonesPurinesPiperazinesPhosphodiesterase InhibitorsPhosphodiesterase 5 Inhibitors3',5'-Cyclic-GMP PhosphodiesterasesErectile DysfunctionCyclic Nucleotide Phosphodiesterases, Type 5Penile ErectionHomosexuality, MaleVasodilator AgentsMethamphetamineCyclic GMPGeorgiaUnsafe SexRisk-TakingSexual BehaviorDrug-Related Side Effects and Adverse ReactionsTreatment OutcomeDouble-Blind MethodDose-Response Relationship, DrugAntipsychotic AgentsDrug Therapy, CombinationAnalgesics, OpioidClinical Trials as TopicAdministration, OralDrug Administration ScheduleTime FactorsNauseaAntineoplastic AgentsVomitingDrug EvaluationPainAdministration, TopicalAnalgesicsProspective StudiesPain, PostoperativeBasal Ganglia DiseasesPain MeasurementNeoplasmsAnti-Inflammatory Agents, Non-Steroidal