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Levothyroxine administration — GPhC CRA MCQ

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HardEndocrine TherapeuticsLevothyroxine administrationGPhC CRA

A patient with newly diagnosed primary hypothyroidism has marked weight loss, postural hypotension, hyperpigmentation and hyponatraemia. Levothyroxine is prescribed but adrenal function has not been assessed. What should the pharmacist do?

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Correct answer: B — Assess adrenal function and establish cover before prescribed levothyroxine starts

Assess adrenal function and establish cover before prescribed levothyroxine starts: The clinical pattern suggests primary adrenal insufficiency; thyroid hormone can increase cortisol clearance and demand, precipitating adrenal crisis if glucocorticoid deficiency is untreated. Take a cortisol sample and start levothyroxine while awaiting the result: Obtaining a sample may be useful, but suspected adrenal insufficiency must be addressed before thyroid hormone exposure. Start low-dose levothyroxine and monitor blood pressure, sodium and symptoms: A lower thyroid dose does not reliably prevent adrenal decompensation. Correct sodium and start levothyroxine before adrenal testing: Hyponatraemia may be a manifestation of cortisol deficiency and electrolyte correction alone does not make thyroid treatment safe. Defer both adrenal and thyroid management to routine review: The features raise a potentially life-threatening diagnosis requiring urgent assessment rather than routine delay.

Reference: BNF: levothyroxine sodium: https://bnf.nice.org.uk/drugs/levothyroxine-sodium/