Opportunities for i.v. to oral switch in the management of infections: the role of quinolones

Quinolones are an important group of drugs for the oral treatment of severe infections. We have shown that in patients with bacteremia the serum levels of fleroxacin are high enough to treat Gram-negative infections with one single oral dose per day. Thus for severe, quinolone-sensitive infections, such as bacteremic pyelonephritis, the switch from i.v. to oral may be done even on the first day of infection if the patient is not in shock and able to take oral medication. Staphylococcal infections have been successfully treated in animal models and non-randomized human studies with the combination of quinolone and rifampin. We have studied the influence of rifampin on the pharmacokinetics of fleroxacin in normal volunteers and no dose adjustment appears necessary. A single daily oral dose of fleroxacin (400 mg) and rifampin (600 mg) appears to be a promising therapeutic approach for staphylococcal infections and is the basis for an ongoing prospective randomized clinical trial comparing early switch to oral bitherapy with standard i.v. therapy. In conclusion, fleroxacin as a single drug or in combination with rifampin is a promising approach for switch from i.v. to oral therapy of severe Gram-negative and possibly staphylococcal infections.