Maximum non-reactive concentration of midazolam and ketamine for skin testing study in non-allergic healthy volunteers.

The objective of our study was to determine the maximal non-reactive concentrations for midazolam and ketamine in healthy volunteers using both prick and intradermal skin tests. Twenty-one healthy Caucasian volunteers were tested for midazolam and ketamine using more clustered concentrations (identical for both prick and intradermal tests) than those resulting from decimal dilutions. The criteria for positivity were based on dilutions of drugs that cause wheal and flare reactions in subjects without history of allergy. For the prick method, the concentrations that did not produce wheal and flare were 1 mg/ml for midazolam and 10 mg/ml for ketamine. For intradermal tests, using serial dilutions, we found that the highest concentration for which the subjects did not pass the positivity criteria was 0.25 mg/ml for both drugs.