[Pharmacokinetics of penicillins following combined administration with sulfanilamides]

Combined use of benzylpenicillin or ampicillin with sulfalen or sulfadimethoxine resulted in a decreased binding of the antibiotics to the blood serum proteins and slower elimination of penicillins from the experimental rabbits. It is quite possible that the decreased levels of the antibiotic binding to the proteins caused their slower elimination rates, which was realized by increasing the volume of the drug distribution mainly at the expense of the peripheral compartment and decreased excretion with the urine.