Tazpen Drug Interactions

Probenecid: Concurrent administration of probenecid and Piperacillin/Tazobactam produced a longer half-life and lower renal clearance for both piperacillin and tazobactam. However, peak plasma concentrations of neither drug are affected.
Vancomycin: No pharmacokinetic interaction is found between TAZPEN and vancomycin.
Aminoglycosides: No interaction is found between TAZPEN and tobramycin. Whenever TAZPEN is used concurrently with another antibiotic, especially an aminoglycoside, the drug must not be mixed in intravenous solutions or administered concurrently due to physical incompatibility.
The inactivation of aminoglycosides in the presence of penicillin class drugs has been recognised. It has been postulated that penicillin-aminoglycoside complexes form; these complexes are microbiologically inactive and of unknown toxicity. Hence whenever TAZPEN is used concurrently with another antibiotic, especially an aminoglycoside, the drug must not be mixed in IV solutions or administered concurrently due to physical incompatibility.
Heparin: Coagulation parameters should be tested more frequently and monitored regularly during simultaneous administration of high doses of heparin, oral anticoagulants, or other drugs that may affect the blood coagulation system and/or the thrombocyte function.
Vecuronium: Piperacillin when used concomitantly with vecuronium has been implicated in the prolongation of the neuromuscular blockade of vecuronium. TAZPEN could produce the same phenomenon if given along with vecuronium. Due to their similar mechanism of action, it is expected that the neuromuscular blockade produced by any of the non-depolarising muscle relaxants could be prolonged in the presence of piperacillin. Caution is indicated when piperacillin is used perioperatively with vecuronium and similar neuromuscular-blocking agents.
Methotrexate: Limited data suggests that co-administration of methotrexate and piperacillin may reduce the clearance of methotrexate due to competition for renal secretion. If concurrent therapy is necessary, serum concentrations of methotrexate as well as the signs and symptoms of methotrexate toxicity should be frequently monitored.
Effects on laboratory tests: As with other penicillins, the administration of piperacillin/tazobactam may result in a false-positive reaction for glucose in the urine using a copper-reduction method. It is recommended that glucose tests based on enzymatic glucose oxidase reactions be used.
Incompatibilities: Whenever Tazpen is used concurrently with another antibiotic, the drug must be administered separately. The mixing of Tazpen with an aminoglycoside in vitro can result in substantial inactivation of the aminoglycoside.
Because of chemical instability, Tazpen should not be used in solutions containing only sodium bicarbonate.
Tazpen should not be mixed with other drugs in a syringe or infusion bottle since compatibility has not been established.