Side by side

1. 1.Binds the melanocortin-2 (ACTH) receptor on cells of the adrenal cortex.
2. 2.Stimulates cortisol synthesis and release within 30 to 60 minutes.
3. 3.The size of the cortisol rise is the test result: a flat response indicates adrenal insufficiency.
4. 4.Has no meaningful effect on mineralocorticoid pathways at diagnostic doses.
5. 5.Depot formulations extend adrenal stimulation over days.

• Short ACTH stimulation (Synacthen) test for primary adrenal insufficiency
• Assessment after long-term steroid therapy
• Diagnostic work-up of suspected secondary adrenal insufficiency
• Adrenal response in critical illness research
• Short-term inflammatory conditions with the depot form

• A cortisol rise above the locally defined threshold in people with normal adrenal function
• Detection of adrenal suppression after prolonged steroid use
• No therapeutic effect beyond stimulating the adrenal cortex at diagnostic doses

• Transient flushing
• Nausea
• Injection-site reactions
• Hypersensitivity, including rare anaphylaxis
• Fluid retention and electrolyte shifts with repeated depot use
• Worsening of allergic or asthmatic symptoms rarely reported with depot use

Research context only - diagnostic use. The standard short test uses 250 micrograms intramuscularly or intravenously with cortisol sampled at baseline, 30 and 60 minutes; low-dose variants use 1 microgram with more sensitive assays. Interpretation thresholds differ between assays and are set locally.

Research context only