Hi, welcome to our site. I am Dr Kalpesh Kavar, MD. Read your query. That is a very significant question and i appreciate your problem. I will try my best to answer your query Amoxicillin and Amlodipine are having separate mechanism of action and different path of metabolism which doesn t interact with each other. As you have been prescribed amoxicillin for sinus infection which can be continued along with Blood pressure lowering drug Amlodipine. As far as tootache is concerns, it may be infection spread or may be entirely new cause for tootache, which needs to be confirmed from detailed examination, but it surely can not be due to interaction between amoxicillin & amlodipine. I hope this helps you. Inform the reports mentioned above/if any other so I can be of help further. I have given you the answer to the maximum considering the information provided. The results of the tests could further enhance my answer to you. Please do understand that some details could be extracted from a detailed history and examination. Please feel free to ask another query. I would be glad to help you. Looking forward to your return query with the details asked so that I can help you further. Take care.