Hi, welcome to the forum. Yes it can be quite possible. Such reactions are known as photo allergic eruptions which are bit different from photo toxic eruptions. It is usually a lymphocyte-mediated reaction caused by exposure to Ultra violet rays. Some drugs are known to transform in to certain chemicals which is responsible for such reactions.
Coumarin can be later converted to 6-methyl coumarin which is responsible for such reactions. Other drugs which can cause photoallergy are phenothiazines, chlorpromazine, sulfa products, and NSAIDs etc. I suggest you to consult physician for other alternatives. Take care and regards.