Hello, thank you for putting your trust in our site, my name is Dr.Abdullah Soliman abd I will be glad to answer your question. I don t think 5 hydroxytryptophan is suggestive for flight anxiety as it may used for alcohol withdrawal, insomnia, post menstrual syndrome and headaches, but I think that Xanax is more suggestive by taking the minimal dose prior to the flight and will relax you and put you to sleep, also it will not interfere as a drug interaction with the meds you are taking either the high blood pressure medication or biotin which is a supplement and mostly has no interactions. I hope this answer fulfill your query and if you are satisfied with the answer please consider giving 5 star rating , and feel free to ask any additional questions and I will gladly help you with an answer.