Cortrosyn (Cosyntropin) Reconstitution Protocol
Standard Reconstitution Method
Reconstitute the 0.25 mg Cortrosyn lyophilized vial by adding 1 mL of sterile 0.9% sodium chloride to produce a final concentration of 0.25 mg/mL (250 mcg/mL). 1
Step-by-Step Reconstitution Procedure
- Sanitize the vial stopper with 70% isopropanol before needle puncture 1
- Use sterile technique throughout the preparation process, avoiding direct contact contamination of sterile needles and syringes 1
- Add 1 mL of sterile 0.9% sodium chloride (without phenol preservative preferred) to the lyophilized vial 1
- Mix gently until the powder is completely dissolved—do not shake vigorously 1
- Perform visual inspection after mixing to ensure complete dissolution and absence of particulate matter 1
- Warm to room temperature before administration if the solution was refrigerated 1
Dosing Aliquots for ACTH Stimulation Tests
High-Dose (Standard) Test
Administer the entire 0.25 mg (250 mcg) dose intravenously or intramuscularly for the standard cosyntropin stimulation test. 2, 3 This is the FDA-approved dose and is recommended over low-dose testing due to easier practical administration, comparable diagnostic accuracy, and regulatory approval. 2
Low-Dose Test (When Specifically Indicated)
For a 1 mcg low-dose test, dilute the reconstituted solution further:
- Draw up 0.1 mL of the 0.25 mg/mL solution (containing 25 mcg)
- Add to 2.4 mL of sterile 0.9% sodium chloride to create a 2.5 mL solution containing 10 mcg/mL
- Administer 0.1 mL of this diluted solution (1 mcg dose) 4
Note: The low-dose test requires bedside dilution, making it less practical for routine clinical use, and the high-dose test is preferred in standard practice. 2 However, in patients with obesity (BMI >30), a weight-adapted dose of 0.2 mcg/kg may be more appropriate than the fixed 1 mcg dose. 5
Storage Recommendations
Unreconstituted Vials
- Store sealed lyophilized vials at room temperature with desiccation if using bulk powder, though FDA-approved prepackaged vials do not require desiccation or freezing 1
Reconstituted Solutions
- Refrigerate at 4°C immediately after reconstitution 1
- Use within 24 hours when reconstituted with sterile 0.9% sodium chloride without phenol 1
- Discard any unused solution remaining in the vial or syringe after administration 1
- Do not store reconstituted solutions at room temperature for extended periods, as this accelerates degradation 1
Critical Reconstitution Considerations
Avoid adding preservatives such as phenol to the diluent unless specifically required by the manufacturer, as preservative-free sterile saline is preferred and widely used. 1 The pH of cosyntropin in normal saline is weakly to moderately acidic, and buffered solutions should not be used as they are less stable. 1
Label the reconstituted vial clearly with the drug name, concentration, reconstitution date, and expiration time. 1