Drug provocation tests
Placebo-controlled single blinded DPT with the culprit drug was only done in mild NIDHRs with negative ST and after a careful risk-benefit assessment.8,33 The DPT was sequential and additive when symptoms remitted and laboratory parameters became normal, not earlier than 4 weeks. Initially 1/100 of the therapeutic dose was administered. If tolerated, a dose of 1/10 was given 3 days to 1 week later, depending on the drug and the time interval between drug intake and the reaction. If tolerated, the full therapeutic dose was given after the same interval. If symptoms suggestive of NIDHR appeared, the procedure was stopped and the symptoms were evaluated and treated. Medications were stopped before DPT according to international guidelines.33