Background The intensity of postoperative pain depends on the type of surgical procedure. However, it can be a problem finding the optimal treatment.

Purpose To improve medical analgesics prescription according to pain intensity, considering warnings and main drug interactions.

Materials and methods We did a bibliographic review from January 2004 to August 2013 in several databases (PubMed, Micromedex, Cochrane, etc.) and scientific journals.

Results We designed a postoperative analgesia protocol based on a pain severity prediction according to the type of surgical procedure performed.

For surgical procedures associated with mild-moderate pain:

Intravenous infusion in 100 ml physiological saline at 2 ml/h for 50 h:

Type 1: tramadol 6 mg/ml

Type 1-RI (renal impairment): tramadol 4 mg/ml

Type 2: metamizole 120 mg/ml

Type 3: ketorolac 1.8 mg/ml

Type 3-RI: ketorolac 1.2 mg/ml

Type 4: tramadol 6 mg/ml + metamizole 120 mg/ml

Type 4-RI: tramadol 4 mg/ml + metamizole 120 mg/ml

Type 5: tramadol 6 mg/ml + ketorolac 1.8 mg/mlType 5-RI: tramadol 4 mg/ml + ketorolac 1.2 mg/ml

For surgical procedures associated with severe pain:

Intravenous infusion in 100 ml physiological saline at 2 ml/h for 50 h:

Type 1: morphine 0.3 mg/ml + droperidol 0.025 mg/ml

Type 2: morphine 1 mg/ml PCA (patient-controlled analgesia)

Type 3: morphine 0.3 mg/ml + metamizole 120 mg/ml

Type 4: morphine 0.3 mg/ml + dexketoprofen 3 mg/ml

Epidural infusion in 250 ml physiological saline at 5 ml/h for 50 h:

Type 1: bupivacaine 0.1%

Type 2: bupivacaine 0.1% + fentanyl 2 mcg/ml

Concomitant analgesia: Paracetamol IV 1 g/6 h (dose adjustment in liver disease) and metamizole IV 2 g/6–8 h or dexketoprofen IV 50 mg/8 h (depending on the type of protocol).

General recommendations: To prescribe gastroprotective drugs with non-steroidal anti-inflammatory drugs and antiemetic drugs in nausea or vomiting.

Avoid use of intravenous ketorolac or dexketoprofen for more than 2 days.

Rescue analgesia: Morphine IV 0.05 mg/kg/4 h or pethidine IV 25–100 mg/4 h.

Neuropathic pain: Amitriptyline, pregabalin or duloxetine.

Conclusions An analgesics protocol has a role in guiding medical prescriptions and an impact on rational drug use. It contributes to identifying patients who could benefit from a specific drug combination and minimises possible drug side effects.

No conflict of interest.