Q: What is the biggest risk factor for development of Vancomycin induced "Red-Man Syndrome"?



Answer:  Vancomycin related "Red-Man Syndrome" is a mast cell activation phenomenon so any medicine which predispose mast cell activation concomitantly with vancomycin may increase the risk. In ICU, two most common offenders are opioids and radiocontrast dye. Also, two other commonly used drugs in ICU found to increase the risk for similar reasons, are Ciprofloxacin and Succinylcholine. 



References: 

1. Polk RE, Healy DP, Schwartz LB, et al. Vancomycin and the red-man syndrome: pharmacodynamics of histamine release. J Infect Dis 1988; 157:502. 

2. Wong JT, Ripple RE, MacLean JA, et al. Vancomycin hypersensitivity: synergism with narcotics and "desensitization" by a rapid continuous intravenous protocol. J Allergy Clin Immunol 1994; 94:189.