Promethazine - can a person who is allergic to NSAIDS take this medicine?

Yes, anyone with allergies to NSAIDs can take Promethazine. It is a different class of drug to NSAIDs.

Promethazine is in a group of drugs called phenothiazines. It works by changing the actions of chemicals in your brain. Promethazine also acts as an antihistamine. It blocks the effects of the naturally occurring chemical histamine in your body.

Promethazine is used to treat allergy symptoms such as itching, runny nose, sneezing, itchy or watery eyes, hives, and itchy skin rashes.

Promethazine also prevents motion sickness, and treats nausea and vomiting or pain after surgery. It is also used as a sedative or sleep aid.

http://www.drugs.com/promethazine.html