Assessment of the effect of single dose dexamethasone on the hypothalamic-pituitary axis

Double-blind randomised controlled trial assessing the effects of dexamethasone on the hypothalamic-pituitary-adrenal axis in healthy volunteers

Status

Completed

Phases

Phase 4

Study type

Interventional

Source

ANZCTR

Registry ID

ACTRN12611001067965

Enrollment

Registered

2011-10-13

Start date

2011-10-17

Completion date

2011-12-19

Last updated

2020-01-13

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

None listed

Brief summary

Our adrenal glands produce cortisol which is our body’s natural “stress hormone”. Cortisol production is controlled by the hypothalamus and pituitary glands in the brain (hypothalamic-pituitary adrenal axis). This involves a feedback loop to prevent over- or under-production of cortisol. Dexamethasone (a synthetic form of cortisol) has been shown to significantly reduce postoperative nausea and vomiting. Currently most patients having a general anaesthetic receive a single 8mg dose of dexamethasone. This has been studied in relation to a number of different surgery types and in adults appears to be safe and effective. Dexamethasone has a long duration of action, typically quoted to be 36-72hours although the plasma half-life of dexamethasone is shorter at approximately 6 hours. Dexamethasone is used by endocrinologists to assess whether there is cortisol overproduction i.e. “dexamethasone suppression test” as it doesn’t interfere with the laboratory measurement of cortisol. Similar to the overnight dexamethasone suppression test it has been shown that after a single 8mg dose cortisol suppression occurs. What isn't known is how long the cortisol suppression lasts and whether other pituitary hormone levels are also suppressed.

Interventions

Double blind randomised controlled trial assessing the effects of a single dose of 8mg dexamethasone intravenously versus saline control on hypothalamic-pituitary axis suppression in healthy volunteers.

Study design

Allocation

Randomised controlled trial

Intervention model

Crossover

Primary purpose

Prevention

Masking

Blinded (masking used)

Eligibility

Sex/Gender

Male

Age

18 Years to 40 Years

Healthy volunteers

Yes

Inclusion criteria

Healthy male volunteers

Exclusion criteria

Glucocorticoid use within the past 6 months Psychiatric illness Uncontrolled hypertension Diabetes mellitus Shift workers Unable to give informed consent Medications likely to interfere with dexamethasone metabolism Hypothalamic-pituitary target organ axis disease Acute illness

Outcome results