Study of the effects of ticarcillin on blood coagulation and platelet function

Systemic antibiotic agents

Understanding the breadth of systemic antimicrobial agents available for use by the dermatologist and their associated side-effect profiles and drug interactions allows the clinician to offer patients optimal care in the management of cutaneous infectious disease.

Antibiotic side effects

Antibiotic side effects are approached best from an individual agent perspective rather than from a class-related standpoint. As this article indicates, with the exception of drug fevers and drug rashes, most antibiotic side effects are related to individual agents and not class side effects. Clinicians should view antimicrobial side effects as related to each organ system and be aware that more often a nonmicrobial medication is the explanation for the drug side effect rather than the antimicrobial. Nonantimicrobial medications are the most common cause of drug fever; among antimicrobials, beta-lactams and sulfonamides are the most common causes of drug-induced fevers. Antimicrobial side effects have important implications for the patient, legal and economic implications for the hospital, and medicolegal implications for the physician. Antibiotic side effects that prolong hospitalization in today's managed care environment have important economic implications. Clinicians should be familiar with the most common side effects of the most frequently used antimicrobials, to minimize the potential of having adverse reactions occur in patients. Most adverse events related to antimicrobials are reversible rapidly on cessation of the medication. Irreversible toxicities include aminoglycoside-induced ototoxicity, Stevens-Johnson syndrome, and toxicity secondary to nitrofurantoin. The most common acute fatal drug reactions include hypersensitivity reactions resulting in anaphylaxis or the Stevens-Johnson syndrome and fatal hepatic necrosis secondary to trovafloxacin. Clinicians should eliminate the use of drugs associated with chronic or fatal toxicities because multiple therapeutic alternatives exist for virtually every potential infection.

Antimicrobial agents for the dermatologist. I. Beta-lactam antibiotics and related compounds

We review the newer antimicrobial agents that are being employed by dermatologists with increased frequency as well as some of the more commonly used older agents. Particular emphasis is based on selection factors such as causative pathogens and their resistance profiles, routes of administration, toxicity, drug interactions, and dosing requirements. Emphasis in this review is on the newer classes of antimicrobials such as third- and fourth-generation cephalosporins; beta-lactam, beta-lactamase inhibitor combination agents; monobactams; carbapenems; macrolides; and fluoroquinolones. Dermatologic indications and treatment alternatives are highlighted; this will expand the practicing clinician's therapeutic armamentarium and enable him/her to make rational decisions concerning treatment approaches to infectious disease problems encountered in daily practice.

Coagulation disorders in cancer

Coagulation disorders are common in cancer patients. This article reviews the coagulation laboratory findings in these patients and the thromboembolic and hemorrhagic manifestations of malignancy. Among the many topics addressed are Trousseau's syndrome, disseminated intravascular coagulation, and acquired von Willebrand disease. Pathogenesis of the coagulation disorders and recommendations for treatment of various syndromes are discussed.

Platelet function defects associated with hemorrhage or thrombosis

Platelet dysfunction, especially acquired forms, is a common cause of hemorrhage, especially when associated with trauma or surgery. Although the hereditary platelet function defects are generally quite rare, hereditary storage pool disease is common enough to be suspected in an individual, usually a child, with characteristic historical and clinical findings. The acquired platelet function defects, especially those resulting from drugs, are common and should promptly be suspected in patients developing easy and spontaneous bruising, mild-to-moderate mucosal membrane hemorrhage, or unexplained bleeding associated with trauma or surgery. The template bleeding time is generally useful as a screening test of platelet function, but a normal template bleeding time, in the face of a suggestive history, suggestive clinical findings, or in a patient frankly bleeding, is not reliable, and platelet aggregation or lumiaggregation should be done in appropriate clinical situations. Also, prolongation of the template bleeding time is an unreliable predictor of clinical bleeding propensity. The mainstay of therapy for almost all these defects, if bleeding is significant, is the liberal infusion of appropriate numbers of platelet concentrates. The acquired platelet function defects should also be managed by attempts to treat or control the underlying disease, if possible, and offending drugs or potentially offending drugs should immediately be stopped.

Studies of interaction of a low-molecular-weight heparinoid (Org 10172) with cloxacillin and ticarcillin in healthy male volunteers

Pharmacokinetic and pharmacodynamic interactions between Org 10172 (intravenous bolus injection of 3,250 anti-Xa units), which is a low-molecular-weight heparinoid, cloxacillin (500 mg orally four times daily for 3 days), and ticarcillin (4,000 mg intravenously four times daily for 2 days) were evaluated in two separate studies with healthy male volunteers (n = 18). Both cloxacillin and ticarcillin caused a significant increase in elimination half-life of anti-Xa activity, i.e., from 31 +/- 10 to 54 +/- 23 h and from 27 +/- 6 to 42 +/- 13 h, respectively (P less than 0.05). Ticarcillin decreased clearance (11%) and increased apparent volume of distribution (35%) (P less than 0.05), while for cloxacillin, these differences did not reach statistical significance. These changes in disposition of Org 10172 by the penicillins were not accompanied by important pharmacodynamic changes as evaluated by coagulation tests, platelet aggregation, and bleeding time. Cloxacillin appeared to influence blood coagulation (prolongation of the activated partial thromboplastin time and shortening of thrombin time; P less than 0.05) and facilitated thrombin-induced platelet aggregation, which coincided with a shorter bleeding time during the combined treatment in comparison with the time during treatment with Org 10172 alone (P less than 0.05). In conclusion, the disposition of Org 10172 was slightly changed by cloxacillin and ticarcillin, and, unexpectedly, cloxacillin appeared to have mild procoagulant effects.

Formulary conversion of cefoxitin usage to cefotetan: experience at a large teaching hospital

The pharmacy and therapeutics committee at Hartford Hospital recommended replacement of cefoxitin with cefotetan, based on data reported in the literature regarding antimicrobial activity, pharmacokinetic profile, and adverse reactions. Once the recommendation was approved by the medical staff, an intense educational program was instituted, and all orders for cefoxitin were converted to cefotetan with appropriate dosage modifications. A total of 960 patients were treated in the first year; no major patterns of ineffectual therapy or adverse events associated with cefotetan usage have emerged. The mean cost of cefotetan therapy was $180.59, which is $130.26 less per patient than a comparable regimen of cefoxitin (mean cost of therapy $310.85). Based on the data analysis of cefotetan usage for a 12-month period, the actual annual savings due to therapeutic substitution of cefotetan for cefoxitin was $124.961. To further evaluate the clinical efficacy, safety, and savings of this therapeutic interchange, two separate retrospective reviews of patient medical records were performed. The first audit has been previously published in its entirety. In the subsequent audit, 284 additional patient medical charts have been reviewed. These patients received either cefotetan therapy or concomitant therapy of an aminoglycoside combined with either clindamycin or mezlocillin. Clinical outcomes were classified as an empiric cure or improvement for 99.4, 98.5, and 92.9 percent of patients, respectively. In this audit, elevated prothrombin time/partial thromboplastin time values and bleeding episodes were noted infrequently, as were other adverse reactions.(ABSTRACT TRUNCATED AT 250 WORDS)

Impaired hemostasis caused by beta-lactam antibiotics

Beta-lactam antibiotics can directly impair hemostasis by two separate nonimmune mechanisms. First, the NMTT-substituted cephalosporin drugs may cause hypoprothrombinemia by interfering with the hepatic activation of clotting factors II, VII, IX, and X. Second, the antipseudomonal penicillins may cause the bleeding time to be prolonged by interfering with platelet aggregation to physiologic agonists. In surgical patients who are malnourished, have impaired gastrointestinal function, or have renal failure, the potential for these adverse effects is increased. Serious bleeding requires treatment with fresh frozen plasma when hypoprothrombinemia is caused by NMTT-containing cephalosporins, since the prothrombin time returns to baseline relatively slowly after therapy with vitamin K. Hemorrhage caused by beta-lactam-induced platelet dysfunction must be treated with platelet concentrates, since new platelets sufficient to correct the defect do not enter the circulation for several days after treatment with the offending drug is discontinued. The more desirable approach is to prevent hypoprothrombinemia by giving vitamin K prophylaxis and to avoid beta-lactams that impair platelet function in seriously ill patients at increased risk for bleeding.

Antibacterial therapy in patients with malignancies

Patients with malignant disease may be predisposed to bacterial infections because of neoplastic disruption of normal tissue barriers, exogenous immunosuppressive therapy (drugs with or without radiation), and intrinsic host immune deficits secondary to these diseases. Diminished polymorphonuclear leukocyte numbers or function and impaired humoral immunity are highly correlated with the development of serious bacterial infections. The usual signs and symptoms of infection may be absent or altered in a compromised host. Therapy must be instituted promptly upon clinical suspicion of bacterial infection, and empirical choices should usually include combinations that are synergistic for likely pathogens based on knowledge of the local predominant flora and susceptibility data. Synergism has most often been demonstrated in combinations that utilize a beta-lactam (semisynthetic penicillin or cephalosporin) and an aminoglycoside. Triple drug therapy has not been shown to be advantageous. Monotherapy with third generation cephalosporins, carbapenems, monobactams, or ureidopenicillins has not been proven to offer advantages over 2-drug regimens for these patients. Patients with blood deficient in granulocytes (granulocytopenic) who respond to 2-drug therapy but remain deficient in neutrophils (neutropenic) may need continued treatment until the neutropenia subsides. Those who do not respond and remain febrile with an unclear focus of infection may need to be started on antifungal therapy in addition to the antibacterial agent. The use of oral agents for the prophylaxis of neutropenic patients against bacteremia remains controversial. If drugs are used, co-trimoxazole and nystatin suspension may be preferable.

Effect of latamoxef (moxalactam) and its related compounds on platelet aggregation in vitro--structure activity relationships

Latamoxef, 1-S replaced and/or decarboxylated derivatives of latamoxef, compounds possessing a partial structure of latamoxef, and a beta-lactam ring-opened derivative of latamoxef were examined for their effects on human platelet aggregation in vitro. Latamoxef produced a dose-dependent inhibition of ADP-induced platelet aggregation at high concentrations over about 2000 micrograms/ml (or 4 mM), and the potency was similar to that produced by cefotaxime, carbenicillin or ceftizoxime. Replacement of the oxygen atom in the oxacephem ring with a sulfur atom caused no significant change in the potency. The decarboxylated derivatives of latamoxef and the 1-S replaced analogue of latamoxef showed stronger inhibition for both ADP- and collagen-induced aggregation than the parent compounds. The effects of the compounds possessing a partial structure of latamoxef were weaker than that of latamoxef, but the effect of the beta-lactam ring-opened compound was about 3-fold stronger than that of latamoxef. These data suggest that neither the oxygen atom in the oxacephem ring nor the carboxyl group in the amide side chain is responsible for the inhibitory effect of latamoxef on platelet aggregation.

Randomised study of ticarcillin, cefamandole with or without tobramycin in febrile, neutropenic patients with solid tumors

A prospective randomised study was conducted comparing the efficacy and toxicity of the antibiotics ticarcillin and cefamandole (TC) with or without tobramycin (TCT) in 100 febrile neutropenic patients with solid tumours undergoing conventional chemotherapy. In this study, neutropenia less than 100/microliter was noted in 31% of 106 evaluable infectious episodes and neutrophil counts less than 1,000/microliter persisted for a median 4 days. Infection was microbiologically documented in 42% of episodes (bacteremia 24%) with gram-negative organisms responsible for 63% of bacterial isolates. Overall, 65% of episodes responded to TC and 76% to TCT (p greater than 0.05). Patients with initial shock bacteremia, pulmonary infection, or gram-negative sepsis responded relatively poorly. Neutrophil nadir and pathogen susceptibility did not influence outcome. Antibiotic toxicity was minimal with no tobramycin-related nephrotoxicity. These results are broadly comparable to those observed with leukemic patients, but the relatively short duration of neutropenia in the solid-tumour patients appears to minimize the need for additional antibiotics provided there is adequate antimicrobial coverage with the initial choice of antibiotics.

Side effects of cephalosporins

Cephalosporins generally cause few side effects. Hypersensitivity reactions are less common than with the penicillins and modern studies have presented data contradicting a true cross-reactivity to cephalosporins in patients who have previously reacted to penicillins. Other hypersensitivity reactions to cephalosporins include fever, arthralgia and exanthema observed in two clusters of children who had been given cefaclor. Nephrotoxicity is not a problem with modern cephalosporins, although slight reductions of renal function have been seen when high doses of ceftazidime were used. Some of the new cephalosporins have a 3-methyl thiotetrazole side-chain, a moiety which confers a risk of reduced synthesis of prothrombin with subsequent risk of bleeding, and of disulfiram-like reactions in patients consuming alcohol following a cephalosporin dose. Other cephalosporins, e.g. ceftriaxone and cefoperazone, are excreted not only via the kidneys but also via the bile. This leads to high biliary concentrations of the active drug, increasing the risk of diarrhoea which may be caused by selection of cytotoxin-producing strains of Clostridium difficile. Laboratory adverse reactions to cephalosporins are rare. Eosinophilia and thrombocytosis are commonly reported, but are most probably not adverse reactions but signs of healing of the infections treated. Other haematological reactions have been reported in very few patients and have been rapidly reversible when treatment was stopped.

In vitro and in vivo studies of the effect of aztreonam on platelet function and coagulation in normal volunteers

The in vitro effects of aztreonam on platelet aggregation were compared with those of cefotaxime, moxalactam, piperacillin, and carbenicillin. In addition, the in vivo effects of intravenously administered aztreonam on blood coagulation and platelet function were examined in 10 normal male volunteers in a randomized crossover study. In vitro, at concentrations of greater than 6.25 mM (2.7 mg/ml), aztreonam inhibited ADP-induced platelet aggregation in a dose-dependent manner. The effect was less than that produced by equimolar concentrations of cefotaxime, moxalactam, piperacillin, or carbenicillin. At all concentrations tested, aztreonam and cefotaxime inhibited epinephrine-induced aggregation least. All antibiotics inhibited collagen-induced aggregation, but only at inordinately high concentrations (25 mM). In vivo studies in 10 male subjects, randomly infused intravenously with 2 g of aztreonam or saline placebo every 6 h for 21 consecutive doses in a single-blind crossover study, revealed no evidence of bleeding or visible adverse side effects. Although plasma coagulation and platelet adhesion remained within normal limits in all subjects throughout the study, inhibition of ADP-induced platelet aggregation significantly (P less than 0.0001) increased on days 3 and 6, but still was below 40%. With the exception of one subject who had a mean template bleeding time of 7.3 min (normal, 2 to 7 min at 95% confidence limits) on day 6 of aztreonam administration, all volunteers exhibited bleeding times within the normal range. No abnormalities in platelet morphology were observed. Mean peak serum aztreonam concentrations on days 1 and 6 were 90.1 +/- 16.7 and 95.9 +/- 13.7 micrograms/ml, respectively; accumulation did not occur. Thus, in normal volunteers, aztreonam produced no significant recognizable abnormalities of hemostasis after 6 days of maximal recommended doses.

Ticarcillin plus clavulanic acid (Timentin) therapy for osteomyelitis

Timentin is an exciting new antibiotic agent that is a combination of ticarcillin and clavulanic acid. Forty-seven patients with osteomyelitis received 3.1 g of Timentin intravenously every six hours. The mean duration of therapy was 32 days. The diagnosis was made by bone biopsy; bone biopsy was repeated at the completion of therapy. The bacterial etiology was predominately gram-positive organisms. Of the organisms isolated, Staphylococcus aureus was the most common isolate and represented 39 percent of the total isolates. Streptococcus species were isolated in 13 percent, Group D Enterococcus in 15 percent, Pseudomonas aeruginosa in 10 percent; 23 percent of the isolates were other gram-negative organisms. All but one organism were initially sensitive to Timentin. Three resistant organisms were isolated during therapy. Twenty-seven patients were classified as having a cure, based on no growth on repeat bone biopsy cultures and clinical signs of bone healing. Twenty-two patients returned for follow-up (one to nine months after therapy) and had no evidence of infection; however, because of the short follow-up period, these patients were classified as showing improvement. Six patients had adverse reactions to Timentin: two had mild allergic phenomena and two had prolonged bleeding times. In all four, therapy was discontinued. Two patients had a transient, mild elevation in the level of serum glutamic-pyruvic transaminase (less than twice normal levels). This new agent looks exciting for therapy of both gram-positive and gram-negative bacterial osteomyelitis.

Effect of temocillin and moxalactam on platelet responsiveness and bleeding time in normal volunteers

The effects of temocillin and moxalactam on platelet responsiveness and bleeding time were examined in healthy male volunteers. In the first study, moxalactam (4 g intravenously every 12 h) was given to six subjects; template bleeding times were at least doubled in five subjects 12 to 14 h after 7 doses (P = 0.008) and in all six subjects 12 to 14 h after 13 doses (P = 0.004). ADP-induced primary aggregation was approximately halved after 7 (P = 0.026) and 13 doses (P = 0.008), and there was a markedly increased tendency toward disaggregation. Collagen-induced aggregation was also halved, but the effect only reached statistical significance after 13 doses (P = 0.008). There was essentially no effect on primary aggregation in response to the thromboxane receptor agonist U46619 or to platelet activating factor. Temocillin (4 g intravenously every 12 h) was given to eight subjects, three of whom had participated in the moxalactam study 8 weeks earlier. Temocillin had no significant effect on template bleeding time 12 to 14 h after 7 or 13 doses. However, in four subjects, the endpoint may have been less abrupt. There was no significant effect on ADP-induced primary aggregation or responsiveness to collagen. Even after 13 doses of temocillin, secondary aggregation in response to normal concentrations of ADP was demonstrable in the platelet-rich plasma of all eight subjects. Neither antibiotic had any effect on prothrombin times. Thus, with methodology that readily detected the effects of moxalactam on hemostasis, we were unable to demonstrate any unequivocal deleterious effects of temocillin at its maximum recommended dose. Temocillin may therefore be particularly useful for the treatment of many gram-negative infections in patients at increased risk of clinical bleeding.

Current guidelines on the use of antibacterial drugs in patients with malignancies

Patients with malignant disease may be predisposed to bacterial infections because of neoplastic disruption of normal tissue barriers, exogenous immunosuppressive therapy (drugs with or without radiation), and intrinsic host immune deficits secondary to these diseases. Diminished polymorphonuclear leucocyte numbers or function and impaired humoral immunity are highly correlated with the development of serious bacterial infections. The usual signs and symptoms of infection may be absent or altered in a compromised host. Therapy must be instituted promptly upon clinical suspicion of bacterial infection, and empirical choices should usually include combinations that are synergistic for likely pathogens based on knowledge of the local predominant flora and susceptibility data. Synergism has most often been demonstrated in combinations that utilise a beta-lactam (semisynthetic penicillin or cephalosporin) and an aminoglycoside. Triple drug therapy has not been shown to be advantageous. Monotherapy with third generation cephalosporins, carbapenems, monobactams, or ureidopenicillins has not been proven to offer advantages over 2-drug regimens for these patients. Granulocytopenic patients who respond to 2-drug therapy but remain neutropenic may need continued treatment until the neutropenia subsides. Those who do not respond and remain febrile with an unclear focus may need to be started on antifungal therapy in addition to the antibacterial agent. The use of oral agents for the prophylaxis of neutropenic patients against bacteraemia remains controversial. If drugs are used, co-trimoxazole and nystatin suspension may be preferable.

Complexation versus hemodialysis to reduce elevated aminoglycoside serum concentrations

Seven patients with acutely elevated aminoglycoside serum concentrations were studied comparing the effect of hemodialysis (n = 3) with removal by complexation using ticarcillin or carbenicillin (n = 4). Aminoglycoside serum half-life before intervention averaged 96 hours for the dialysis group and 67 hours for the complexation group. Ticarcillin was used for a minimum of 48 hours, while hemodialysis removal was estimated over 48 hours, which included two 4-hour dialysis periods. Aminoglycoside serum half-life was reduced to an average of 11 hours with hemodialysis, while with complexation using ticarcillin, it was reduced to 12 hours. During the 48-hour comparison period, complexation removed approximately 50% more aminoglycoside than did hemodialysis, primarily because the improved removal technique was sustained over the entire time. Complexation appears to be as effective as continuous hemodialysis in lowering excessive aminoglycoside serum concentrations. Complexation with ticarcillin can be more rapidly initiated, is less expensive and there is a low risk of adverse reactions. This method provides continued treatment of infections in patients with elevated serum concentrations and/or nephrotoxicity who require cessation of aminoglycoside therapy.

Comparison of the effects of mezlocillin, carbenicillin, and placebo on normal hemostasis

Mezlocillin was compared with carbenicillin and 0.9% NaCl as placebo in a double-blind manner to determine its effect in vivo on hemostasis in normal volunteers. Eighteen subjects were randomized to receive mezlocillin, 4 g every 6 h; carbenicillin, 7.5 g every 6 h; or placebo, 50 ml every 6 h, each given for 20 intravenous doses unless the template bleeding time after 10 doses was greater than 15 min. Template bleeding times were determined before the dose 1 and 1 h after doses 10 and 20. Five of six (83%) subjects receiving carbenicillin developed template bleeding time prolongation to greater than 21 min, and two of six (33%) subjects receiving mezlocillin and one of six (17%) subjects receiving carbenicillin had mild template bleeding time prolongations of less than 13 min. Coagulation studies (prothrombin time, partial thromboplastin time, and thrombin time) were normal in all subjects, and blood salicylate levels were negative. Thus, in standard therapeutic doses, mezlocillin was less likely than carbenicillin to prolong the template bleeding time above normal (P = 0.04) and, when prolongation occurred with mezlocillin, it was mild. These data support the selective use of mezlocillin in patients at increased risk for bleeding and who require therapy with an antipseudomonal penicillin.

Drug interactions with warfarin

Drugs may interact with warfarin through pharmacodynamic or pharmacokinetic mechanisms. Examples of the former include alteration of the bioavailability of vitamin K by antibiotics, mineral oils or cholestyramine; oestrogens, diuretics and hypolipidaemic agents such as clofibrate may influence vitamin K-dependent clotting factor synthesis, and drugs which affect haemostasis, e.g. via platelet function, will enhance the anticoagulant effect of warfarin. Pharmacokinetic interactions are better understood. Few drugs have been shown to alter warfarin absorption, the importance of protein binding displacement has been exaggerated, and since warfarin is not eliminated to any extent unchanged by the kidney, the most important kinetic interactions are those due to inhibition or induction of its hepatic metabolism. Isomeric differences in metabolism form an important basis for stereoselective metabolic interactions, especially inhibition; this has been demonstrated with phenylbutazone, metronidazole and co-trimoxazole. Enzyme induction, although recognised for many years, may still pose problems in therapeutics, usually on withdrawal of the inducing agent.

Penicillin induced human platelet dysfunction and its reversal by epinephrine

Antibiotics administered orally can impair platelet function and cause a bleeding diathesis. Platelet function impairment induced by antibiotics such as penicillin, carbenicillin and tetracycline could be corrected by exposing the refractory platelets to epinephrine first and then challenging with other agonists. Penicillin used in this study inhibited the platelet aggregation response and release reaction without blocking the ability of these platelets to convert arachidonic acid to thromboxane. The thromboxane generated in the presence of penicillin could not activate the platelets when threshold concentrations of arachidonate was used as stimulus. Epinephrine stimulation restored the platelet membrane sensitivity and normalized the platelet response to the action of agonists. These studies demonstrate that both by in vitro as well as in vivo routes penicillin induced temporary impairment of platelet function. The refractoriness was not due to the interference of membrane receptors for various agonists or due to the depletion of serotonin, adenine nucleotides or inhibition of cyclooxygenase activity. Penicillin inhibits some essential mechanism involved in platelet activation by agonists and this process may be calcium dependent. Epinephrine through alpha adrenergic stimulation restores the mechanism by which agonists initiate platelet activation.

Nafcillin-induced platelet dysfunction and bleeding

This paper describes two cases of nafcillin-induced platelet dysfunction, with positive rechallenge data for one patient. Nafcillin resulted in abnormal bleeding times in both patients and a clinically apparent bleeding episode in one of the cases. Platelet function tests were performed on one patient during the initial therapy and after rechallenge with nafcillin. Platelet aggregation showed abnormal responses to ADP, collagen, and epinephrine. Platelet count and morphology were normal. Nafcillin should be recognized as another antibiotic which causes platelet function abnormalities and clinical bleeding episodes.

Carbenicillin and 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.

Effects of sodium piperacillin on platelet function in normal volunteers

Piperacillin is a new semisynthetic penicillin which is similar in structure to carbenicillin and ticarcillin. Since the latter antibiotics have been shown to cause abnormalities in hemostasis, we studied the effects of piperacillin on blood coagulation and platelet function. Fifteen healthy volunteers received the drug in doses of either 100, 200, or 300 mg/kg per day for a period of 7 days. Serial studies showed no abnormalities in blood coagulation in any subject. Decreased platelet aggregation responses to adenosine diphosphate, epinephrine, collagen, and achidonic acid were commonly noted, but prolongation of the bleeding time occurred in only 3 of 15 subjects after 7 days of piperacillin administration. These results suggest that although piperacillin also induces platelet dysfunction, these effects may be less than those caused by ticarcillin or carbenicillin at an equivalent dosage.

Ticarcillin: a review of its pharmacological properties and therapeutic efficacy

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.

Common adverse effects of antibacterial agents on major organ systems

Antibiotics contribute significantly to the management of the surgical patient. However, their potential for adverse effects, both toxic and allergic, must always be kept in mind. We have reviewed the major adverse reactions to antibiotics, so that side effects may be promptly recognized and treated. Armed with this information, the surgeon can more effectively utilize this valuable class of drugs for the benefit of the patient.

Pseudomonas aeruginosa keratitis treated with ticarcillin and tobramycin

A corneal ulcer, infected with Pseudomonas aeruginosa and complicated by conjunctivitis and endophthalmitis, was treated successfully with systemic administration of ticarcillin and topical application of tobramycin. It is unlikely that carbenicillin, to which the organism was much less sensitive, would have attained sufficient tissue levels to control the infection.

Dose-dependent inhibition of experimental arterial thrombosis by carbenicillin and ticarcillin

An experimental model of canine arterial thrombosis was used to study by prophylactic antithrombotic effectiveness of carbenicillin and ticarcillin, two semisynthetic penicillins which have been shown to inhibit platelet function in vivo. Isolated peripheral arterial segments were injected with pronase and biopsied at 24 hours. In untreated dogs, 89% of injected segments totally occluded with thrombus. Prophylactic treatment for 3 to 7 days with carbenicillin or ticarcillin in low doses (250 mg/kg/day) or high doses 750 mg/kg/day) significantly decreased the incidence of total occlusion to 53% and 6%, respectively. The dose-dependent inhibition of arterial thrombosis correlated with dose-dependent inhibition of platelet function. Prophylactic treatment with aspirin in low doses (650 mg/day) or high doses (2600 mg/day) did not significantly decrease the incidence of total occlusion in this model. Carbenicillin and ticarcillin are effective experimental antithrombotic agents.

Inhibition of platelet function by sulbenicillin and its metabolite

The effect of sulbenicillin and its major metabolite, alpha-sulfobenzylpenicilloic acid, on platelet function was investigated. Sulbenicillin caused inhibition of platelet aggregation and release reaction in the same manner as carbenicillin. alpha-Sulfobenzylpenicilloic acid was found to cause much stronger inhibition of platelet function. The results indicate that the strong inhibitory action of alpha-sulfobenzylpenicilloic acid may also take part in impaired platelet functions following administration of sulbenicillin to humans.