Monitor for sedation and other signs or symptoms of over-medication. Consider monitoring TPV concentration. Titrate buprenorphine dose using the lowest initial dose, Tadalafil pills. Monitor for fentanyl-related adverse events, including potentially fatal respiratory depression. Monitor for lofexidine-related adverse events, including symptoms of orthostasis and bradycardia. Titrate methadone dose using the lowest feasible initial dose. Opioid withdrawal is unlikely but may occur. Tramadol dose adjustments may be necessary. Treatment of Erectile Dysfunction: Start with sildenafil 25 mg every 48 hours and monitor for adverse events of sildenafil. For Treatment fix Erectile Dysfunction Erectile Dysfunction: Start with tadalafil 5 mg and do not exceed a single dose of tadalafil 10 mg every 72 hours. Seven days after PI initiation, restart tadalafil at 20 mg once daily and increase to tadalafil 40 mg once daily based on tolerability.