Analgesics and antipyretics — branching viva

Opening — the stem

A five-year-old weighing 18 kg is admitted overnight after a fall with a greenstick fracture of the right radius, reduced and backslabbed in the emergency department. She is tearful and guarding the arm, and is also mildly febrile at 38.6 °C with a viral upper respiratory tract infection. She is alert, drinking and passing urine. The examiner asks you to take the analgesic and antipyretic plan from here. [2]

Q1. "What is your first question, and what is your first drug and dose?"

First, confirm a measured weight in kilograms (18 kg) and score the pain. This child is in moderate pain (guarding, tearful) and is febrile. My first drug is paracetamol, at 15 mg per kg per dose, which for 18 kg is 270 mg per dose, every four to six hours, to a maximum of 60 mg per kg per day (1.08 g per day here, well below the 4 g per day adult cap, which I check explicitly). Because there is an inflammatory component to a fracture, I also give ibuprofen if there is no contraindication: 5 to 10 mg per kg per dose, which is 90 to 180 mg per dose, every six to eight hours, maximum 30 mg per kg per day, from three months and over 5 kg — which she is. She is drinking and passing urine, so the NSAID is safe. [2] [3]

Q2. "The nurse asks whether you should alternate the two. What do you say, and why?"

I do not routinely alternate. The 2024 network meta-analysis shows short-term dual therapy lowers temperature modestly faster than either agent alone, but the effect is small and dual therapy increases the risk of dosing error, parental confusion and doubled or exceeded doses. My position is a single effective agent with a clear plan — I will give both now because she has both pain and fever and an inflammatory component, with a written schedule, a stated maximum daily dose, and a dosing syringe — but I will not set up an every-two-hour alternation, and at discharge I will give the family one clear first-line agent with a rescue plan. I always ask what the family has already given, because the commonest ceiling breach is a second preparation they did not realise contained paracetamol. [1] [2]

Q3. "Her temperature is 38.6. A medical student offers aspirin for the fever. Your response?"

Aspirin is avoided in children under 16 with viral illness because of the association with Reye syndrome, the rare but devastating hepatocerebral syndrome. This child has a viral upper respiratory tract infection and is five years old, so aspirin is contraindicated; paracetamol or ibuprofen is the correct antipyretic. [6]

Q4. "The pain is not controlled three hours later. The student suggests codeine. What is your position?"

Codeine and tramadol are contraindicated in children under 12 and after tonsillectomy or adenoidectomy, because a CYP2D6 ultrarapid metaboliser converts the prodrug into a flood of morphine and the child develops opioid respiratory depression and apnoea — the genotype cannot be identified at the bedside, so the whole population is treated as at risk. This child is five, so codeine is not an option. If her pain is not controlled with regular paracetamol and ibuprofen, the next step is a low-dose opioid — morphine, 0.1 to 0.2 mg per kg intravenously, titrated to the pain score and monitored with a sedation score and respiratory rate — alongside continued multimodal analgesia and review by the acute pain team. [7] [8]

Q5. "She receives the morphine. What are you watching for, and what is your response if it occurs?"

I am watching for opioid-induced respiratory depression: a falling respiratory rate, increasing sedation, and a small or unreactive pupil, monitored with a sedation score and continuous observation in the first hours. If it occurs, my response is airway and breathing support and naloxone titrated to the respiratory rate, not to full reversal — the goal is a breathing child who is still comfortable, not an awake child in pain. Because naloxone's half-life is shorter than morphine's, I monitor for recurrence and am ready to give repeat boluses or an infusion. [12]

Q6. "She is discharged the next day. What do you write and what do you say to the family?"

I write the dose in milligrams (not millilitres alone), with a dosing syringe, the maximum daily dose stated, and a clear schedule for paracetamol and ibuprofen. I teach back to the carers: how much, how often, the daily ceiling, and to avoid combining with any other cold preparation that may contain paracetamol. I give a written safety-net naming the features that should bring her back — reduced feeding, reduced wet nappies, lethargy or drowsiness, a fever that does not settle, increasing pain despite the analgesia, or a non-blanching rash. The fracture follow-up is arranged. The discharge defence is a written dose, a syringe, the daily maximum, and teach-back. [2] [11]