Thanks for the question. I have been taking 100 mg of doxy every morning for about a month now. I was taking it prior to a month ago, very sparingly because I did not have many tablets left. After seeing my doctor and explaining that I also have Lyme Disease and Alpha Gal Allergy from ticks because I live in a very wooded area, I need whatever protection I can get to ward off another tick borne illness. I also have rosacea and Doxy 100 mg daily is the drug of choice. However I wondered if it might just help rid me of constant (bigeminy) heart palpitations. So far, I have after a month, seen on my Kardia device that I have times when there are NO PVCS or SVES and I am in "Normal Sinus Rythym". I have not seen that reading ONCE since last December until after taking the Doxy. The erratic heartbeat is far from gone, but for the first time in over six months, there is finally some improvement!