Epidural anesthesia is given outside the dura in epidural (extradural) space (not in subarachnoid space). Onset of effect takes place in 15-30 minutes (not immediately). In contrast, spinal anesthesia has immediate effect (approximately 5 minutes). Neuraxial block (spinal & epidural) anesthesia is contraindicated in coagulopathy or bleeding diasthesis. Neuraxial block (spinal & epidural) can cause venous pooling and decreased venous return.