Drug Single dose (mg) Analgesia onset time (min) Effect time (h) Epidural Morfin 1-6 30 6-24 Extended release morphine 5-15     Fentanil 0.025-0.1 5 2-4 İntratekal Morfin 0.1-0.3 15 8-24 Fentanil 0.005-0.025 5 3-6

Table 3: Intrathecal and epidural doses and duration of effect of the most comonly used opioids.