Cosyntropin

Indications

For the evaluation of adrenal function in dogs.

Dosage and Administration

The dose is 0.25 mg (1 mL) per dog weighing 10–110 lbs (4.5–50 kg), administered by intravenous or intramuscular injection, with the purpose of performing the adrenocorticotropic hormone (ACTH) stimulation test. Discard unused portion. Cosacthen is provided in a single use vial and does not contain a preservative. Collect the first blood sample to measure the baseline cortisol concentration immediately prior to administering Cosacthen. Collect the second blood sample 1 hour after administration of Cosacthen to measure the dog’s cortisol concentration in response to Cosacthen.

Contraindications

Do not use Cosacthen in dogs that have previously had a hypersensitivity reaction to cosyntropin.

Warnings

USER SAFETY WARNINGS Not for use in humans. Keep this and all drugs out of reach of children. People with known hypersensitivity to cosyntropin or ACTH should avoid contact with the product. Pregnant women and breastfeeding women should take care to avoid accidental self-injection. If any anaphylactic or allergic symptoms (skin reactions, dizziness, nausea, vomiting, urticaria, pruritus, flushing, malaise, dyspnea, angioneurotic edema) develop following exposure to Cosacthen, medical advice must be sought immediately. In case of accidental self-injection, seek medical advice immediately and show the package insert or label to the physician. If skin contact occurs, wash affected area with soap and water.

Precautions

The safe use of Cosacthen has not been evaluated in breeding, pregnant, or lactating dogs.

Adverse Reactions

In the field study using a non-final formulation cosyntropin injection, which included 119 dogs with suspected hypoadrenocorticism or hyperadrenocorticism, two dogs vomited within 8 hours after cosyntropin injection administration, and one dog developed a hematoma at the injection site after IV administration. Clinical pathology abnormalities were consistent with pre-existing hypoadrenocorticism and hyperadrenocorticism. Foreign Market Experience: The following adverse events were reported voluntarily during post-approval use of Cosacthen in dogs in foreign markets: lethargy, anxiety, muscle tremor/weakness, abdominal pain, anorexia, diarrhea, injection site pain/bruising, lameness, and hypersensitivity reactions.

Description

Cosyntropin consists of the first 24 amino acids in naturally occurring adrenocorticotropic hormone (ACTH). The sequence of amino acids in cosyntropin is as follows: Ser-Tyr-Ser-Met-Glu-His-Phe-Arg-Trp-Gly-Lys-Pro-Val-Gly-Lys-Lys-Arg-Arg-Pro-Val- Lys-Val-Tyr-Pro Molecular formula: C 136 H 210 N 40 O 31 S Cosacthen® (cosyntropin injection) is a clear, aqueous solution. Each milliliter contains 0.25 mg cosyntropin, 1 mg glacial acetic acid, 0.82 mg sodium acetate trihydrate, 8.1 mg sodium chloride and water for injection (to 100%).

Storage

Store refrigerated between 2–8°C (36–46°F). Store in provided outer carton to protect from light. Single use vial; discard unused portion.

FDA adverse event reports

The FDA Center for Veterinary Medicine publishes the adverse event reports it receives through openFDA. The counts below are the reports naming cosyntropin as an active ingredient for each species this label names, as returned on 2026-09-16, coded by the VeDDRA reaction term the reporter chose. Reactions are counted per report, so one report can appear under several terms.

These are counts, not rates. Reporting is voluntary, the number of animals treated is not known, and a widely used product accumulates reports for that reason alone. A report records that an event followed a dose; it does not establish that the product caused it. The counts say nothing about how one product compares with another.