Spinal anaesthesia has a rapid onset and complete motor blockade  and also simple to perform. It has lower incidence of failed block and the local anaesthetic requirement is less. Hence spinal anesthesia is a preferred anaesthetic technique for lower abdominal surgeries. Adjuvants to local anaesthetics for intrathecal administration has some advantages. They have synergistic action & intensify sensory block without increasing sympathetic block, reduced local anaesthetic drug dose, better hemodynamic stability with lesser side effects.

Fentanyl is a pure mu receptor agonist. The common mu agonist side effects are  nausea, vomiting, sedation, urinary retention and respiratory depression. It is lipophilic in nature, with rapid onset of action following intrathecal administration. The intrathecal drug administration does not produce respiratory depression. It improves anaesthetic quality without much complications.  Nalbuphine is a mixed kappa agonist and mu antagonist opioid drug, which produces analgesia without much side effects of mu receptor agonist action.

Levobupivacaine is a local anaesthetic amide which can produce better sensory and motor block with good hemodynamic profile than bupivacaine. Levobupivacaine is less cardiotoxic than bupivacaine. ⁽¹⁾ Many investigators have studied the characteristics of intrathecal nalbuphine & fentanyl with levobupivacaine.