Acute intermittent porphyria (AIP) is caused by deficiency of porphobilinogen (PBG) deaminase. Attacks are precipitated by drugs that induce hepatic ALA synthase (ALAS1). Which drug is SAFEST in a patient with known AIP?

• A Barbiturates
• B Sulphonamides
• C Rifampicin
• D Propofol ✓

Explanation

Propofol does not induce CYP450 or ALA synthase and is considered safe in AIP. Barbiturates (phenobarbitone), sulphonamides, and rifampicin are potent CYP inducers that upregulate ALAS1, increasing ALA and PBG production upstream of the deficient enzyme, precipitating acute attacks (neurovisceral pain, hyponatraemia, neuropathy). Givosiran (siRNA against ALAS1) is the approved treatment.

Reference: Harper's Illustrated Biochemistry, 32nd ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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