Ticarcillin

Carbenicillin and ticarcillin are penicillins which were initially developed as agents to treat serious Pseudomonas infections in the seriously ill hospitalized patient. These drugs have made a major contribution to improved survival in the neutropenic patients with Pseudomonas infection, the burn patient and to the care of the patient with cystic fibrosis. Areas of use for the compounds have enlarged to include aspiration pneumonitis in hospitalized patients, intra-abdominal and pelvic sepsis, and infections due to Proteus and Enterobacter species. Careful attention to the pharmacology of the agents is necessary to achieve clinical and bacteriologic success and to avoid the toxic side-effects such as bleeding and hypokalemia associated with the use of these agents. A decade of use has shown that the agents have remained effective agents in institutions in which their use has not been abused. It is too early to clearly position azlocillin, mezlocillin, and piperacillin. In the next few years the role of these potent compounds will be established. As noted in this review, these three agents have been used with success to treat all of the aforementioned infections. With these drugs it is also essential that the physician closely correlate in vitro data and the human pharmacology of the drugs if he or she wishes to achieve the most effective response from the agents.

Ticarcillin is a semisynthetic penicillin for parenteral administration. The antibacterial activity of ticarcillin is similar to that of carbenicillin except that it is two to four times more active in vitro against Pseudomonas aeruginosa, generally less active against Gram-positive cocci and more active against most Gram-negative bacilli. As the pharmacokinetics of ticarcillin and carbenicillin are also similar, ticarcillin should theoretically be clinically effective when administered at a lower dosage than carbenicillin. There is some evidence that ticarcillin is comparable in efficacy with carbenicillin when given in half to two-thirds the dosage, when the drugs are given in combination with an aminoglycoside and in clinical situations where these drugs are agents of choice. Ticarcillin has been used successfully in the treatment of complicated urinary tract infection, pulmonary infection in cystic fibrosis and bacteraemia and is effective when combined with an aminoglycoside in severe infections in patients with granulocytopenia. The efficacy in anaerobic infections is at present poorly documented, although preliminary results are promising. Tolerability has generally been good with hypokalaemia being the most frequently reported side effect. At the dosages used, bleeding and fluid overload have seldom occurred.

An accurate, plate diffusion bioassay for ticarcillin, utilizing the fast-replicating Beneckea natriegens and 4% salt agar, is described in this report. Zones of inhibition were well defined after 3 h, and the limit of sensitivity was around 5.0 mug/ml. The assay is simple to carry out, and duplicate assays can be performed on as little as 40 mul of serum.