Hello, well, I feel bad that this situation is happening to you. If you discussed this topic with your doctor? In this situation, I recommend you look for information on the internet at health-related sites. Also, I would recommend you to read articles from Jennifer Anyabuine. She is writing about multiple medications, so you may find a proper medication that will be effective for a long period. I'm not familiar with the tachyphylaxis phenomenon, but I'm sure modern medicine has a good answer to this diagnosis. If you are interested, reach me in private messages. I will share with you Jennifer Anyabuine's articles.