Background: Intravenous antibiotics are often evaluated in clinical trials in hospitalised patients but for blinded trials masking of antibiotics is required.
Objective: To evaluate the effectiveness of masking of ceftriaxone and amoxicillin / clavulanic acid for use in blinded clinical trials.
Design setting and participants: Amoxicillin / clavulanic acid (1.2g) and ceftriaxone (1g and 2g) were diluted in 100mL of sodium chloride. Clinicians from a single centre were asked to attempt to distinguish solutions containing antibiotics from solutions without added antibiotics at time points up to 12 hours following dilution.
Results: 1g of ceftriaxone diluted in 100 mL of 0.9 sodium chloride stored in a light-protected bag and refrigerated at 3-4 °C for up to 10 h could not readily be distinguished from 100 mL of 0.9 % sodium chloride. However, solutions containing either amoxicillin / clavulanic acid (1.2g) or ceftriaxone (2g) were readily identifiable.
Conclusions: 1 g of ceftriaxone can be effectively masked by dilution in 100mL of sodium chloride.
Keywords: Antibiotic; Blinding; Clinical trials; Masking; Performance bias.
© 2023 The Authors.