Peptide education
Cosyntropin
Cortrosyn · Tetracosactide · ACTH 1-24
Cosyntropin is a synthetic piece of ACTH used to stimulate the adrenal glands during a cortisol test.
Cortrosyn helps screen for adrenocortical insufficiency in adults and children alongside other tests. Results depend on sampling, the cortisol assay, medicines, and the clinical situation; the test is not a treatment for adrenal failure.
Overview
Quick answer
Cortrosyn is a diagnostic preparation. It is not the repository corticotropin gel used for conditions such as infantile spasms, and the two products have different formulations and doses.
How is the test used?
Cortrosyn is given by a clinician, and cortisol is measured before and after the injection as part of an adrenal assessment.
Is the dose the same at every age?
No. The U.S. label specifies 0.125 mg from birth to under two years and 0.25 mg from age two onward.
Does a normal response settle every adrenal question?
No. A negative result may not rule out secondary adrenal insufficiency. The label also notes that assays, medicines, and cortisol-binding changes can affect interpretation.
What about lower-dose testing?
One patient-level analysis found better discrimination with low-dose testing in selected patients. A later review found similar accuracy for low- and high-dose tests in secondary adrenal insufficiency.
Evidence
Evidence snapshot
Cortrosyn is used with other tests to assess adrenocortical insufficiency.
The dose for children under two is half the labeled dose for older children and adults.
Patient-level data covered suspected chronic hypothalamic-pituitary adrenal insufficiency.
Prior hypersensitivity to cosyntropin or product ingredients is a contraindication.
Claims
Common claims vs evidence
| Claim | Human evidence | Verdict |
|---|---|---|
| A cosyntropin injection treats adrenal insufficiency. | The Cortrosyn label describes its use as a diagnostic agent for screening, combined with other tests. | A stimulation test and hormone replacement are different clinical purposes. |
| Low-dose testing is always more accurate for every patient. | A patient-level analysis found better low-dose discrimination among paired results; a later review found similar accuracy for low- and high-dose tests in secondary insufficiency. | The analyses used different methods and study selections. Neither establishes that low-dose testing is always more accurate. |
| One universal cortisol threshold applies to all laboratories. | The label says the cutoff for excluding insufficiency can vary with the cortisol assay and that medicines or binding proteins can affect results. | Interpretation depends on the assay and the patient's clinical context. |
Bottom line
Main takeaway
The test measures how the adrenal glands respond to an ACTH-like signal.
Medicines and medical conditions can alter the measured result; clinicians decide how to manage them before testing.
Compare test protocols using the relevant patient population, reference standard, assay, and technical method.
Identity
What it is
Cosyntropin contains the first 24 amino acids of ACTH and stimulates adrenal corticosteroid secretion.
Cortrosyn is supplied as 0.25 mg of powder in a single-dose vial for reconstitution and intravenous or intramuscular administration.
Use context
Routes, doses, and cycle patterns
The Cortrosyn label specifies an age-based single test dose and a schedule for cortisol sampling.
Human studies and product labels
Cortrosyn, birth to under two years
- Purpose
- Adrenal insufficiency screening with other tests
- Context
- U.S. prescription label
- Route
- Intravenous or intramuscular
- Amount
- 0.125 mg, equivalent to 125 mcg
- Frequency
- Single test dose
The label calls for cortisol samples at baseline and exactly 30 and 60 minutes after injection.
Cortrosyn, age two through 17 and adults
- Purpose
- Adrenal insufficiency screening with other tests
- Context
- U.S. prescription label
- Route
- Intravenous or intramuscular
- Amount
- 0.25 mg, equivalent to 250 mcg
- Frequency
- Single test dose
The same labeled sampling schedule applies; interpretation may vary by cortisol assay.
What varies
- Glucocorticoids, spironolactone, estrogen-containing medicines, and conditions affecting cortisol-binding globulin can interfere. Medication changes require the treating clinician's direction.
Research
Research evidence
The product label establishes the screening context. Two diagnostic reviews reached different conclusions about low- versus standard-dose testing in people assessed for central or secondary adrenal insufficiency.
| Study / evidence area | Population | Design | Product context | Main outcome | Limitations | Weight |
|---|---|---|---|---|---|---|
| Patient-level ACTH test meta-analysis | 679 people in 13 studies of suspected chronic hypothalamic-pituitary adrenal insufficiency | Meta-analysis using insulin hypoglycemia or metyrapone reference tests | Low-dose and standard-dose corticotropin stimulation protocols | Among 254 participants with paired results, diagnostic curve areas were 0.94 for low dose and 0.85 for standard dose | Patient-level data were available for 13 of 23 studies; low-dose testing has technical limitations | Diagnostic evidence for a selected population |
| ACTH test systematic review | 1,209 adults and 228 children in 30 studies of suspected secondary adrenal insufficiency | Systematic review and meta-analysis of high- and low-dose ACTH tests | High-dose and low-dose stimulation protocols | The review found similar diagnostic accuracy for both doses, with generally low sensitivity and high specificity | A negative test did not reliably rule out secondary insufficiency; confidence in the estimates was low to moderate because of bias, heterogeneity, and imprecision | Diagnostic evidence across studies with differing methods |
| Cortrosyn prescribing information | Adults and pediatric patients assessed for adrenocortical insufficiency | U.S. prescription label | Single intravenous or intramuscular diagnostic dose | Cortisol is measured before injection and at 30 and 60 minutes | Assay cutoffs, medicines, binding proteins, and clinical context affect interpretation | Labeled test context |
Cautions
Safety and unknowns
- Hypersensitivity, including anaphylaxis, has been reported. Cortrosyn is contraindicated after hypersensitivity to cosyntropin or its ingredients.
- Postmarketing reports include slow or fast heart rate, high blood pressure, swelling, and rash; their frequency cannot be estimated from those reports.
- Incorrect interpretation can result from drug effects or changes in cortisol-binding globulin. Do not stop prescribed medicines without clinical guidance.
Product quality
Product identity and quality
The labeled product is a single-dose vial that requires reconstitution before intravenous or intramuscular administration.
Age and units
The under-two dose is 0.125 mg, while the older-child and adult dose is 0.25 mg.
Correct preparation
Cortrosyn is not interchangeable with a repository corticotropin gel.
Mechanism
How it is proposed to work
Cosyntropin provides an ACTH-like signal that prompts the adrenal cortex to release cortisol.
A cortisol response is interpreted as part of a diagnostic assessment rather than as a measure of treatment benefit.
FAQ
Common questions
Does one cortisol number diagnose every form of adrenal insufficiency?
No. The label notes assay-dependent cutoffs and interference from medicines and conditions affecting cortisol binding; clinicians interpret the test with other information.
Details
Technical details
Sources
References
- 1.
DailyMed. Cortrosyn prescribing information
Adrenal screening indication, age-specific doses, sampling, and test limitations.
- 2.
PubMed. Corticotropin tests for hypothalamic-pituitary-adrenal insufficiency: a metaanalysis
doi:10.1210/jc.2008-0710 PMID:18697868
Patient-level analysis of low- and standard-dose tests for suspected chronic central adrenal insufficiency.
- 3.
doi:10.1210/jc.2015-1700 PMID:26649617
Systematic review of high- and low-dose ACTH tests, including studies of secondary adrenal insufficiency.
- 4.
DailyMed. Acthar Gel prescribing information
Separate repository corticotropin therapeutic product.