- Prednisolone at anti-inflammatory or immunosuppressive dosages in conjunction with doxycycline does not potentiate the severity of Rickettsia rickettsii infection in dogs. Breitschwerdt, E.B., Davidson, M.G., Hegarty, B.C., Papich, M.G., Grindem, C.B. Antimicrob. Agents Chemother. (1997)