Answer
Yes. It can suppress the skin response and produce a false-negative result. Ask the testing clinic when it should be withheld.
Sources for this answer
- Sominex — Current selected SmPCemc · Summary of Product Characteristics
- Phenergan 25 mg tablets — Current selected SmPCemc · Summary of Product Characteristics
General medicine information. Follow the instructions for your own medicine and speak to a pharmacist or clinician about your individual circumstances.