Thank you for your reply Sheryl.
When I first moved to live in Thailand nine years ago I had been on Monocycline for several years, but of course could not find it in Thailand. I tried the Doxycycline but found that it actually increased my susceptibility to sun burn, so much so that even just walking down the road, complete with hat, my chin, nose and cheeks would burn. Then I moved on to Tetracycline and the sun burn stopped and all has been good for the succeeding years. It is a mystery to me why the stock of Tetracycline have suddenly disappeared, and just wondering if there is a prob