I had encephalitis or meningitis (not sure) last September. Anyway, I got a PICC line and had doxycycline running through it for nearly two months. Two weeks ago I was in terrible pain and was in the hospital because I developed blood clots in my arm and the causticity of the doxy burned the veins and surrounding tissue in my chest. I have never known a worse agony and misery. My veins were all constricted in defense mode. I read on the internet that doxy should never be given through a PICC line long term. I'm so angry with my doctor for letting this happen to me. I have Lyme disease and have suffered immensely with it for five years, but this took the cake. I HATE antibiotics!