Metyrapone suppression test

INDICATION

    • To establish the correct functioning of the ACTH axis in suspected secondary hypocortisolism, where Insulin tolerance or glucagon stress tests are contraindicated.

    • As an alternative to the Short Synacthen Test for evaluation of primary hypocortisolism.

CONTRAINDICATIONS

Previous adverse reaction to metyrapone.

SIDE EFFECTS

Most commonly nausea and perhaps vomiting with the medication (reduced by taking metyrapone with a snack).

Headaches, dizziness and sedation, allergic skin reactions.

PREPARATIONStop all oestrogen therapy 6 weeks prior to test.

No need to fast.

18-20g cannula.

Red top Vacutainer (plain clotted) x 1, Purple top Vacutainer (EDTA) x 1.

Vacutainer adaptor for cannula.

METHOD

Admit to hospital for a night’s stay.

Calculate dose of metyrapone (30 mg/kg):

Body weight Dose of metyrapone

<70 kg 2.0 g

70-90 kg 2.5 g

>90 kg 3.0 g

Administer calculated dose of metyrapone at midnight with a snack (e.g. milk and biscuits).

At 0800h-0900h the following morning, sample for ACTH, 11-deoxycortisol, cortisol.

After blood sample, administer hydrocortisone 10 mg PO to cover for hypocortisolism.

Patient can be discharged home after hydrocortisone given.

INTERPRETATION

SENSITIVITY AND SPECIFICITY

The performance of the Metyrapone test has been compared to the ITT as a gold standard in various studies. Using the criteria as above (Courtney 2000) the specificity is 77% and sensitivity 86%.

REFERENCES

Steiner H, Bähr V, Exner P, Oelkers PW. Exp Clin Endocrinol. 1994;102(1):33-8.

Fiad TM, Kirby JM, Cunningham SK, McKenna TJ. Clin Endocrinol (Oxf). 1994 May;40(5):603-9.

Courtney CH, McAllister AS, McCance DR, Hadden DR, Leslie H, Sheridan B,

Atkinson AB. Clin Endocrinol (Oxf). 2000 Sep;53(3):309-12.

Gibney J, Healy ML, Smith TP, McKenna TJ. J Clin Endocrinol Metab. 2008 Oct;93(10):3763-8.

VERSION HISTORY

TT 05/09.