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Acute Porphyria Drug Safety — RACP Adult Medicine MCQ

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ModerateClinical PharmacologyAcute Porphyria Drug SafetyRACP Adult Medicine

A 32-year-old woman presents with sudden onset colicky abdominal pain and dark red urine. She has tachycardia and hypertension. Her sodium is 128 mmol/L. Random urine shows elevated porphobilinogen and aminolaevulinic acid. She is known to have acute intermittent porphyria. Which of the following drugs is SAFE to use in this patient?

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Correct answer: A — Paracetamol

Many drugs are unsafe in acute porphyria as they induce hepatic ALA synthase via CYP induction. Carbamazepine, barbiturates, sulfonamides, and rifampicin are all UNSAFE. Paracetamol is considered SAFE and can be used for analgesia. Opioids (morphine, fentanyl) are also safe and commonly needed for the severe abdominal pain of porphyric crises. The Australian Drug Database for Acute Porphyria should be consulted before prescribing any medication.

Reference: eTG – 2025 – Haematology; AMH – 2025 – Porphyria Drug Safety