Tetracosactide

Summary

Tetracosactide (cosyntropin) is a synthetic 24-amino acid peptide corresponding to the first 24 residues of natural ACTH. It is primarily used as a diagnostic agent to assess adrenocortical function (Synacthen test) and therapeutically for conditions responsive to corticosteroids. It retains full biological activity of endogenous ACTH with a lower risk of allergic reactions compared to animal-derived ACTH.

Mechanism of Action

Tetracosactide binds to melanocortin type 2 receptors (MC2R) on adrenal cortex cells, activating adenylate cyclase and increasing intracellular cAMP, which stimulates synthesis and secretion of corticosteroids (cortisol, aldosterone, and androgens) from the adrenal cortex.

Routes of Administration

Goals & Uses

• Differentiation of primary vs. secondary adrenal insufficiencyDiagnosticHigh
• Diagnosis of adrenocortical insufficiencyDiagnosticHigh
• Infantile spasms (West syndrome)NeurologyModerate
• Multiple sclerosis relapseTherapeuticModerate
• Treatment of inflammatory and autoimmune conditionsTherapeuticModerate

Contraindications

• Hypersensitivity to tetracosactide or ACTHAllergy/ImmunologicHigh
• Pregnancy (therapeutic use)ReproductiveModerate
• Cushing's syndromeEndocrine DisorderHigh
• Systemic infections (untreated)InfectiousHigh
• Active peptic ulcerGastrointestinalModerate
• Adrenocortical hyperfunctionEndocrineHigh

Adverse Effects

• HyperglycemiaMetabolicUncommonAbnormally high blood glucose
• HypertensionCardiovascularUncommonHigh blood pressure
• Injection site reactionsLocalCommon
• Fluid retention / edemaFluid / ElectrolyteCommon
• Allergic/anaphylactic reactionImmunologicUncommon
• Cushing's syndrome features (with prolonged therapeutic use)EndocrineUncommon

Drug Interactions

• Live vaccinesHigh
• CiclosporinModerate
• Antidiabetic agentsModerate
• NSAIDsModerateMay increase renal risk in susceptible patients
• Diuretics (potassium-wasting)Moderate

Population Constraints

• Pediatric patients (infants)AgeRelative
• Patients with osteoporosisMusculoskeletalRelative
• Elderly patientsAgeRelative
• Pregnant womenReproductiveRelative
• Diabetic PatientsMetabolicRelative

Regulatory Status

• European UnionApprovedApproved: Diagnostic testing of adrenocortical function, Inflammatory and allergic disorders, Infantile spasms, Multiple sclerosis relapsesAvailable as Synacthen (immediate-release) and Synacthen Depot (zinc phosphate complex) in most EU member states.
• United StatesApprovedApproved: Diagnostic testing of adrenocortical functionMarketed as Cortrosyn (cosyntropin); FDA-approved for diagnostic use only. Depot form not approved in the US.
• United KingdomApprovedApproved: Diagnostic testing of adrenocortical function, Therapeutic use in steroid-responsive conditionsLicensed as Synacthen and Synacthen Depot; regulated by MHRA.

Approved in many countries including the EU and UK as Synacthen (standard) and Synacthen Depot (depot formulation). In the US, cosyntropin (Cortrosyn) is the equivalent approved diagnostic agent (FDA-approved). The depot form is not widely approved in the US.

Evidence & Sources

No sources recorded yet.