Patients will be randomly allocated in a 1:1 ratio to one of the two treatment groups determined by a computer-generated random sequence. This gives all the patients equal (50/50) chance of being placed in either group. This reduces bias and ensures fair comparison of the treatment being studied. The study will be conducted in a single-blind manner, wherein the patients will be blinded to their group allocation, while the investigators and clinical staff will be not blinded. To maintain blinding at the patient level, identical-appearing intranasal spray devices containing either Tapentadol 22.5 mg per nostril (Group TP) or normal saline (Group NS), ensuring similarity in appearance, volume, and administration technique. Pain assessments will be conducted by an independent obese to treatment allocation to minimize assessment bias.

Groups P : (STANDARD ANALGESIC REGIME)

This group will receive Intravenous Paracetamol 15mg/kg, thrice daily (not exceeding 4g/day) + Inj.Ketorolac IV 30mg twice daily + Intranasal normal saline 2 sprays 0.1ml in the same nostril for each dose (1ml) twice daily from postoperative day 0 to  postoperative day 3.

GROUP TP : (Intranasal Tapentadol group)

This group will receive Intravenous Paracetamol 15mg/kg, thrice daily (not exceeding 4g/day) + Inj.Ketorolac IV 30mg twice daily + Intranasal Tapentadol two sprays (i.e.) 22.5mg per spray in the same nostril for each dose (45mg), twice daily from postoperative day 0 to postoperative day 3.

After obtaining approval from the Institutional Research Committee and Institutional Ethics Committee, patients fulfilling inclusion criteria will be recruited for the study and informed consent will be obtained. Patient will be educated about the study protocol and how to express VNRS for level of pain. Patient’s demographic details- Age, co-morbidities, surgical data will be documented. Patients will be randomly allocated (1:1) into either Group NS or Group Tp.

On the day of surgery patient will receive spinal anaesthesia with 0.5% hyperbaric bupivacaine plus 60mcg of buprenorphine (volume of LA based on patients demography) as per the primary OT anaesthesiologist.

Duration of surgery, intraoperative blood loss, intraoperative adverse events such as arrythmias, hypotension will be documented.

At the end of surgery, patient will be shifted to postoperative care unit (PACU). Sensory blockade level will be assessed. When the patient complains of a VNRS- static > 3, patient will receive the first dose of Intravenous Paracetamol and assessed after 30 mins, if the VNRS  is >3 persistently then Intravenous Tramadol (1mg/kg) is administered. End of 6 hours after receiving paracetamol, patients will receive intranasal saline/ tapentadol based on their group allocation and repeated every 12 hours .Patient will be assessed 30 mins post spray for pain relief and tabulated in VNRS.