Post-tonsillectomy analgesia: a codeine order and a home acetaminophen dose
Malik, age 6, weighs 24 kg, is 18 hours post tonsillectomy and is admitted for poor oral intake. His orders read: acetaminophen 15 mg/kg PO every 6 hours as needed for pain, and codeine 0.5 mg/kg PO every 6 hours as needed for breakthrough pain. He is otherwise healthy, takes no daily medications, and has no known drug allergies. At 14:00 his pain score is 6/10 and he is due for analgesia. His mother mentions that at 12:30, because he was crying, she gave him 10 mL of the acetaminophen 160 mg/5 mL suspension she brought from home. She also has a bottle of 'nighttime cold' liquid in her bag that she says 'usually helps him sleep.' The pharmacy stocks acetaminophen 160 mg/5 mL and codeine 15 mg/5 mL. The unit's standing order sets the maximum acetaminophen dose at 75 mg/kg/day.
1. Calculate Malik's ordered acetaminophen dose in mg and mL, and determine whether the 14:00 dose can be given. Show your work and state what else you must verify.
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Ordered dose: 24 kg × 15 mg/kg = 360 mg. The elixir is 160 mg/5 mL, or 32 mg/mL, so 360 ÷ 32 = 11.25 mL. Do not give it at 14:00. The mother gave 320 mg (10 mL × 32 mg/mL) at 12:30, only 1.5 hours earlier. A q6h PRN order means the next dose is not due until 18:30. Check the daily ceiling: 75 mg/kg/day × 24 kg = 1,800 mg. The home dose plus four scheduled 360-mg doses would be 320 + 1,440 = 1,760 mg, under the ceiling but close enough that any additional acetaminophen-containing product could push him over. Before any dose, verify the home product's label and concentration from the bottle rather than memory, confirm the exact time and amount, and screen the 'nighttime cold' liquid for acetaminophen or other ingredients. Reassess pain, offer ice chips or a popsicle if allowed, and give the ordered dose at 18:30 only if needed. Document the home dose, the hold, and the teaching.
2. Evaluate the codeine order. What is your response, and what alternatives should you raise with the prescriber?
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Do not administer the codeine. Codeine is contraindicated for pain management in children under 12 and after tonsillectomy or adenoidectomy in anyone under 18, because CYP2D6 ultrarapid metabolizers convert it rapidly to morphine and have died of respiratory depression. A 6-year-old immediately after tonsillectomy is squarely inside that contraindication. The ordered dose would be 0.5 × 24 = 12 mg, or 4 mL of the 15 mg/5 mL solution, but no calculation makes the drug safe here. Notify the prescriber, state the contraindication plainly, and request a different plan. Reasonable alternatives are scheduled acetaminophen plus an NSAID such as ibuprofen if there is no contraindication (bleeding, dehydration, renal concern), with a low-dose opioid such as morphine reserved for severe breakthrough pain and accompanied by monitoring. Also examine the cold product: many contain acetaminophen, antihistamines, or cough suppressants that are not recommended for young children and create duplication risk. Document the notification and the new plan.
3. What discharge teaching would you give to prevent another medication near-miss?
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Use teach-back rather than a handout alone. Read every label together and have the mother point to the acetaminophen content and concentration; explain that 'cold' and 'sleep' products often contain acetaminophen and that two products can add up to an overdose. Show her the dosing device and have her draw up 11.25 mL, then state the next safe time and the 75 mg/kg/day ceiling. Emphasize recording each dose with the time, not relying on memory, and never using a kitchen spoon. Advise avoiding over-the-counter cough and cold products in a young child and calling the clinic for pain that is not controlled, poor drinking, fever, bleeding, or unusual sleepiness. Keep all medicines locked and out of reach, including a visitor's purse. Ask her to repeat the plan in her own words, provide written instructions at her health literacy level, and document the teaching and her understanding.