What is the recommended dosing for chlorhexidine (CHG)?

Recommended Dosing for Chlorhexidine (CHG)

For skin antisepsis before central venous catheter insertion and site care, 2% chlorhexidine gluconate in 70% isopropyl alcohol is the recommended concentration and formulation. 1

Concentration and Formulation Guidelines by Application

For Skin Antisepsis:

• Central venous catheter insertion: 2% CHG in 70% isopropyl alcohol 1
• Central neuraxial blockade (epidural/spinal): 0.5% CHG in 70% alcohol is recommended due to neurotoxicity concerns with higher concentrations 1
• Hand hygiene preparations:
  • 4% CHG is most effective but has higher risk of dermatitis with frequent use 1
  • 2% CHG is slightly less effective than 4% but better tolerated 1
  • 0.5% or 0.75% aqueous CHG formulations are more effective than plain soap but less effective than 4% CHG preparations 1

Application Method:

• Allow antiseptic to air dry completely before catheter insertion or dressing application 1
• For central venous catheter site care, disinfect catheter connectors, ports and hubs preferably with 2% CHG in 70% isopropyl alcohol 1
• When preparing surgical patients, two scrubs are superior to one scrub for reducing skin bacterial colony counts 2

Special Populations and Precautions

Pediatric Considerations:

• Not recommended for infants younger than two months due to potential side effects including systemic absorption 1
• In preterm infants with birthweight less than 1000g, higher risk of skin erythema has been observed 1

Safety Precautions:

• Avoid contact with eyes when using preparations >1% as it can cause conjunctivitis and severe corneal damage 1
• Avoid direct contact with brain tissue and meninges due to neurotoxicity 1
• Avoid use in surgery involving inner or middle ear due to ototoxicity 1
• For patients with chlorhexidine sensitivity, alcoholic povidone-iodine solution should be used instead 1

Efficacy Considerations

CHG has several advantageous properties:

• Broad-spectrum antimicrobial activity against nearly all bacteria and yeasts 1
• Faster onset and longer duration of action than povidone iodine 1
• Retains efficacy in the presence of blood 1
• Substantial residual activity on skin 1
• Addition of low concentrations (0.5%-1.0%) of CHG to alcohol-based preparations results in greater residual activity than alcohol alone 1

Common Pitfalls to Avoid

1. Dilution considerations: While diluting CHG to concentrations as low as 0.4% may still maintain antiseptic efficacy 2, manufacturer recommendations should be followed when available.

2. Compatibility issues: CHG is a cationic molecule, and its activity can be reduced by:

   • Natural soaps
   • Various inorganic anions
   • Nonionic surfactants
   • Hand creams containing anionic emulsifying agents 1
   • Will cause stains if used with chlorine releasing products such as bleach 3

3. Toxicity management: In case of accidental ingestion, first aid involves using anionic materials as CHG is a cation 4

4. Skin irritation: The frequency of skin irritation is concentration-dependent, with 4% formulations most likely to cause dermatitis when used frequently 1

By following these evidence-based guidelines for CHG concentration and application, healthcare providers can optimize infection prevention while minimizing adverse effects.