Post-operative analgesia — OSCE prescribing station

The stem

Mr Saleh has just returned from theatre after an open repair of a large incisional hernia with mesh. There is no epidural. Prescribe his regular and as-required analgesia and the drugs that should go with it.

Patient details

Patient: Mr Omar Saleh, 54 years
Weight: 80 kg
Allergies: None known
eGFR: 88 mL/min/1.73 m²
Past history: No asthma, no peptic ulcer, no heart disease
Pain now: 7 out of 10 at rest

Drug chartTo write

Drug (generic name)	Dose	Route	How often / rate	Notes

Write the drug, dose, route and frequency, and sign every entry.

The examiner’s questions

Question 1Write his analgesia prescription.Show the model answer

Drug (generic name)	Dose	Route	How often / rate	Notes
Paracetamol	1 g	Oral or IV	Every 6 hours, regular	Maximum 4 g in 24 hours
Ibuprofen	400 mg	Oral	Every 8 hours, regular, with food	Review at 72 hours
Morphine sulfate oral solution	5 to 10 mg	Oral	Up to every 2 hours as required	For moderate to severe pain
Ondansetron	4 mg	Oral or IV	Up to every 8 hours as required	For nausea or vomiting
Senna	15 mg	Oral	At night, regular	While on opioids
Naloxone	100 to 200 micrograms	IV	As required	For respiratory depression; repeat if needed

If he cannot take oral medicines, patient-controlled analgesia with morphine (for example 1 mg bolus, 5-minute lockout, no background infusion) can replace the oral morphine.

Question 2Why prescribe several drugs instead of one strong one?Show the model answer

This is multimodal analgesia. Each drug acts in a different way, so together they control pain better and reduce the opioid dose, and therefore opioid side effects such as sedation, nausea, constipation and ileus. Regular simple analgesia is the foundation; the opioid is added on top.

Question 3On day 2 his eGFR falls to 35. What do you change?Show the model answer

Stop the ibuprofen, because non-steroidal anti-inflammatory drugs worsen acute kidney injury. Opioids and their metabolites build up in renal impairment, so reduce the dose and frequency of morphine and monitor sedation and respiratory rate closely. Look for the cause of the kidney injury, which is most often too little fluid. Ask the pharmacist or the pain team for advice.

Question 4What else must you write and check on the chart?Show the model answer

The allergy box completed, generic drug names, the word “micrograms” written in full, no trailing zeros (1 mg, not 1.0 mg), a maximum daily dose for as-required drugs, and your signature, printed name, date and contact number.

After you answerThe teaching pointShow

Prescribe analgesia regularly, not only as required, in the first days after major surgery. Pain that is controlled lets the patient breathe deeply, cough and walk, which prevents chest infection and clots.

The patients are written for teaching and are not real. Doses are typical adult doses; always check the current formulary and your hospital’s guidelines before prescribing.