N-acetylcysteine (NAC) Infusion Should Be Administered in 5% Dextrose or Normal Saline Solution
N-acetylcysteine (NAC) infusion should be diluted in either 5% dextrose in water (D5W), 0.9% sodium chloride (normal saline), or 0.45% sodium chloride (half-normal saline) prior to intravenous administration. 1
Appropriate Diluents for NAC Infusion
According to the FDA drug label for intravenous N-acetylcysteine, the following diluents are recommended:
- 5% Dextrose in Water (D5W)
- 0.45% Sodium Chloride (Half-Normal Saline)
- 0.9% Sodium Chloride (Normal Saline)
The FDA drug label specifically states that "acetylcysteine must be diluted in sterile water for injection, 0.45% sodium chloride injection (1/2 normal saline), or 5% dextrose in water prior to intravenous administration" due to its hyperosmolar nature (2600 mOsmol/L). 1
Osmolarity Considerations
The choice of diluent affects the final osmolarity of the solution:
| NAC Concentration | Osmolarity in Sterile Water | Osmolarity in 0.45% NaCl | Osmolarity in D5W |
|---|---|---|---|
| 7 mg/mL | 91 mOsmol/L | 245 mOsmol/L | 343 mOsmol/L |
| 24 mg/mL | 312 mOsmol/L | 466 mOsmol/L | 564 mOsmol/L |
Stability of NAC Solutions
Research confirms that NAC maintains excellent stability in all three recommended diluents:
- NAC 60 mg/mL diluted in 0.9% sodium chloride, 0.45% sodium chloride, or 5% dextrose and stored in PVC bags at 25°C was found to be chemically and physically stable for at least 72 hours. 2
Clinical Applications and Considerations
For Acetaminophen Overdose
The standard protocol for acetaminophen overdose involves a loading dose followed by maintenance doses, with NAC diluted in one of the recommended solutions. 1
For Contrast-Induced Nephropathy Prevention
When NAC is used for prevention of contrast-induced nephropathy, it is typically administered with intravenous hydration. The Canadian Society of Nephrology notes that in the Acetylcysteine for Contrast Nephropathy Trial (ACT), most participants (98%) received NAC with 0.9% normal saline solution. 3
For Pediatric Patients
In pediatric patients, there is evidence supporting the use of NAC in 0.45% sodium chloride with 5% dextrose to avoid potential hyponatremia. A study using this combination with a modified two-stage dosing regimen showed good safety outcomes. 4
Practical Considerations
- The diluted NAC solution can be stored for 24 hours at room temperature. 1
- The color of the diluted solution may range from colorless to a slight pink or purple once the vial stopper is punctured, which does not affect the quality of the product. 1
- For patients at risk of contrast-induced AKI, normal saline solution is often preferred due to its broad availability and lower cost compared to sodium bicarbonate solutions. 3
Cautions
- Ensure appropriate dilution before administration due to the hyperosmolar nature of NAC.
- Monitor for hypersensitivity reactions during and after administration.
- In patients with renal or cardiac compromise, careful monitoring is essential during fluid administration to avoid iatrogenic fluid overload. 3
By following these guidelines, NAC infusion can be safely administered in the appropriate diluent based on the clinical scenario and patient needs.