Pharmacodynamic activity of five oral cephalosporins against Haemophilus influenzae

STUDY OBJECTIVES

To determine the time above minimum inhibitory concentration (T > MIC) and serum bactericidal activity of five oral cephalosporins against two strains of Haemophilus influenzae.

DESIGN

Randomized, crossover study.

SETTING

University-associated research center.

SUBJECTS

Ten healthy volunteers.

INTERVENTIONS

Each subject received a single dose of cefpodoxime 200 mg, cefuroxime 500 mg, cefaclor 500 mg, cefprozil 500 mg, or loracarbef 400 mg each week for 5 weeks. Blood for serum levels was obtained at time zero and 1, 2, 3, 4, 6, 8, and 12 hours after each dose.

MEASUREMENTS AND MAIN RESULTS

Cefpodoxime produced serum concentrations above the MIC for more than 90% of the time for both beta-lactamase-negative and -positive strains of H. influenzae. Moreover, it had serum bactericidal activity for 12 hours against both isolates. Cefuroxime was the second most active cephalosporin, with serum concentrations above the MIC of both isolates for 60% of the time. Cefuroxime provided serum bactericidal activity for 12 hours against the beta-lactamase-negative strain and 6 hours against the beta-lactamase-positive strain of H. influenzae. Even though the T > MIC was less than 50% of the study period for the other cephalosporins, all but cefaclor provided serum bactericidal activity for 12 hours against the beta-lactamase-negative isolate. Cefaclor provided measurable serum bactericidal activity for only 3 hours. The duration of serum bactericidal activity of cefprozil, loracarbef, and cefaclor against the beta-lactamase-positive isolate was 4, 2, and 0 hours, respectively.

CONCLUSION

Cefpodoxime was the most active cephalosporin studied based on T > MIC and serum bactericidal activity against isolates of H. influenzae.

Pharmacology of new antiherpes agents: famciclovir and valacyclovir

Limitations of acyclovir in treating infections caused by herpes simplex virus include the development of resistant isolates and relatively poor oral bioavailability. Penciclovir and famciclovir may have added clinical utility in the treatment of herpes virus infections in humans. Intracellular pharmacokinetics differ for valacyclovir and famciclovir, but the importance of these differences is unknown. Animal studies suggest that famciclovir (but not valacyclovir) can affect subsequent latent infection with HSV-1; the relevance of these findings to humans requires further investigation. Famciclovir and valacyclovir appear to decrease time to resolution of pain compared with acyclovir in patients with herpes zoster infections.

Pharmacokinetics and pharmacodynamics of newer fluoroquinolones

Newer fluoroquinolones currently under development have excellent pharmacokinetic profiles, and several parameters have been improved compared with those of their predecessors. These compounds are well absorbed, have large volumes of distribution, and distribute into most tissues at concentrations equal to or greater than those observed in serum. Moreover, these newer agents have long serum elimination half-lives that allow for once-daily dosing. With the exception of complexes with multivalent cations that retard absorption, there is a relative lack of clinically significant drug-drug interactions with these antimicrobials. Increased microbiological potency against several important pathogens, along with an enhanced pharmacokinetic profile, will make these newer fluoroquinolones preferable over older compounds for the treatment of a variety of infections.

Prevention of recurrent vaginal candidiasis with weekly terconazole cream

OBJECTIVE

To investigate the prophylactic use of weekly terconazole 0.8% cream to prevent recurrent episodes of candidal vaginitis.

DESIGN

Women with a documented history of recurrent candidal vaginitis (> or = 4 recurrences/y) were enrolled into a secondary prevention trial. None of these women were HIV positive, pregnant, diabetic, or immunosuppressed. Patients were initially treated for a symptomatic episode of candidal vaginitis and then started on weekly applications of terconazole 0.8% cream for 26 weeks. These women were then followed for an additional 26 weeks after therapy.

SETTING

A university-affiliated medical school.

PARTICIPANTS

The study population consisted of 22 healthy women aged 19-41 years.

MAIN OUTCOME MEASURES

Patients were interviewed by phone each week concerning symptoms and compliance. They were also reminded to notify the study investigators any time vaginal symptoms of candidiasis occurred. Patients were examined whenever they developed vaginal symptoms and were treated on the basis of microscopic and culture results.

RESULTS

Ten patients had 14 symptomatic cases of vaginitis during the prophylactic phase of the study, but Candida spp. were isolated during only 4 of these episodes. One episode was due to bacterial vaginosis and no pathogenic organisms were found in 9 of these cases. Eighteen of the 20 patients who completed the prophylactic phase were followed after therapy and 14 (78%) of these patients had a current case of candidal vaginitis. This incidence of infection was statistically higher than that observed during the treatment period (p < 0.001).

CONCLUSIONS

Weekly applications of terconazole 0.8% cream were effective in preventing recurrent episodes of candidal vaginitis and were well tolerated.

A preliminary study of clarithromycin versus doxycycline in the treatment of nongonococcal urethritis and mucopurulent cervicitis

In a comparison of drug safety and efficacy, 40 adult outpatients with clinical signs and symptoms of nongonococcal urethritis or mucopurulent cervicitis were treated with either clarithromycin 250 mg or doxycycline 100 mg twice/day for 7 days. Clinical and laboratory evaluations were repeated during, at the end, and 3 weeks after the completion of therapy. Isolation and susceptibility tests of Chlamydia and Mycoplasma isolates were performed at each visit. All but one patient who received doxycycline were clinically cured or improved at the end of treatment. Two (10%) patients who received clarithromycin and three (15%) who received doxycycline had clinical relapses of the infection. All isolates of Chlamydia trachomatis were eradicated and did not recur in both groups. Doxycycline was more effective than clarithromycin in eradicating Ureaplasma urealyticum (p < 0.01). Both groups reported a high frequency of minor adverse effects, but no patient discontinued therapy. Overall, clarithromycin was clinically safe and effective treatment in patients with nongonococcal urethritis and mucopurulent cervicitis.

Pharmacokinetics, nephrotoxicosis, and in vitro antibacterial activity associated with single versus multiple (three times) daily gentamicin treatments in horses

Once-daily administration of aminoglycosides may be a safe and effective therapeutic regimen, on the basis of the microbiologic and pharmacokinetic characteristics of these antibiotics. This study was designed to determine serum and tissue concentrations following i.v. administration of gentamicin, at dosages of 6.6 mg/kg of body weight, every 24 hours, and 2.2 mg/kg, every 8 hours, for 10 days in adult horses. Nephrotoxicosis from these dosage regimens also was compared, and microbiologic effects, including postantibiotic effects, were determined with various concentrations of gentamicin against an equine clinical isolate of Pseudomonas aeruginosa. Treatment at the 6.6-mg/kg dosage resulted in maximal serum concentrations (77.93 +/- 19.90 micrograms/ml, mean +/- SEM) and area under the concentration-vs-time curves (83.79 +/- 14.97 micrograms.h/ml) that were significantly (P < 0.05) greater than those following treatment at the 2.2-mg/kg dosage (5.05 +/- 0.50 micrograms/ml and 6.03 +/- 0.66 micrograms.h/ml, respectively). Nephrotoxicosis was not induced with either dosage regimen, and postantibiotic effects were prolonged with a higher gentamicin concentration. This study provided evidence to support the use of once-daily gentamicin treatment in adult horses.

Single oral dose fluconazole compared with conventional clotrimazole topical therapy of Candida vaginitis. Fluconazole Vaginitis Study Group

OBJECTIVES

Candida vaginitis is currently treated with a wide range of intravaginal preparations usually prescribed over several days. Fluconazole with its marked activity against Candida species and favorable pharmacokinetics offered a safe, effective, and convenient alternative to topical therapy in a single-dose regimen.

STUDY DESIGN

We conducted a multicenter, randomized, prospective, single-blinded study of 429 patients with acute Candida vaginitis, comparing the efficacy and safety of a single oral 150 mg dose of fluconazole with 7-day clotrimazole 100 mg vaginal treatment. Posttherapy evaluations and mycologic eradication rates were conducted.

RESULTS

No statistically significant differences were seen between fluconazole and clotrimazole in the clinical, mycologic, or therapeutic responses. At the 14-day evaluation clinical cure or improvement was seen in 94% of fluconazole-treated patients and 97% of clotrimazole-treated patients. Mycologic and therapeutic cures were seen in 77% and 76% of the fluconazole and 72% of the clotrimazole groups, respectively. At the 35-day evaluation 75% of both groups remained clinically cured, and 56% of the fluconazole and 52% of the clotrimazole group were considered therapeutic cures. In both treatment groups patients with a history of recurrent vaginitis (33/84) compared with those without a history of recurrent vaginitis (177/266) were significantly less likely to respond clinically and mycologically (p < 0.001). Twenty-seven percent of the fluconazole-treated patients and 17% of the clotrimazole-treated patients reported mild side effects only.

CONCLUSION

Fluconazole administered as a single 150 mg oral dose proved to be as safe and effective as 7 days of intravaginal clotrimazole therapy for Candida vaginitis. Therapy of vaginitis should be individualized, taking into consideration severity of disease, history of recurrent vaginitis, and patient preference.

Antibiotic utilization and cost analysis in hospitalized patients with community-acquired pneumonia

All cases of presumptive community-acquired pneumonia (CAP) in adult patients admitted to a community/teaching hospital during the first 6 months of 1993 were reviewed. A total of 67 patients ranging in age from 20-90 years (73% > 60 years) had CAP. Fifteen (22%) patients were receiving antibiotics before admission. A typical respiratory pathogen was identified in only 18 (27%) patients. Empiric parenteral antibiotics were initiated in all but 2 patients. These agents usually included cefuroxime (42%), ampicillin/sulbactam (28%), or ceftriaxone (14%). Concomitant erythromycin (25%) or clarithromycin (17%) was used empirically in 42% of patients. Parenteral antibiotics were given for a mean of 5.2 days (median, 4 days). The mean therapy cost of these common parenteral agents ranged from $69.50 (cefuroxime, 750 mg every 8 hours) to $271 (ceftriaxone, 1 gram every 12 hours). Hospitalization ranged from 2-37 days (mean, 8.3 days; median, 6 days). A total of 50 patients were switched to oral antibiotics. Prescriptions for outpatient therapy ranged from 5-21 days (mean, 8.6 days; median, 7 days). The most common oral antibiotics included cefuroxime (33%), clarithromycin (20%), and amoxicillin/clavulanate (20%). The mean therapy cost for these drugs ranged from $85.19 (cefuroxime, 500 mg every 12 hours) to $39.24 (clarithromycin, 500 mg every 12 hours). This study found that empiric therapy with low-dose parenteral cefuroxime, with or without erythromycin, followed by outpatient clarithromycin was less costly than other common regimens used to treat CAP.

Placebo-controlled trial of intravaginal clindamycin 2% cream for the treatment of bacterial vaginosis

OBJECTIVE

To compare the safety and efficacy of intravaginal clindamycin 2% cream with placebo in nonpregnant women with bacterial vaginosis.

DESIGN

A randomized, double-blind, placebo-controlled clinical trial.

SETTING

Ambulatory patients in the general community.

PATIENTS

Two hundred fifteen nonpregnant outpatients with a diagnosis of bacterial vaginosis were entered into this study. Of the 134 evaluable patients, 65 received clindamycin and 69 placebo. Demographic parameters were comparable between the two treatment groups.

INTERVENTION

Study subjects were equally randomized to receive either 5 g of clindamycin 2% vaginal cream or placebo cream for seven nights.

MAIN OUTCOME MEASURES

Clinical and microbiologic follow-up evaluations were scheduled for 5-10 days and 25-39 days posttreatment. Patients were interviewed about signs and symptoms, adverse events, and compliance. Diagnostic examinations were performed.

RESULTS

Clinical success rates (cure and improvement) occurred in 50 of 65 patients who received clindamycin (77 percent) and 17 of 69 patients who received placebo (25 percent) by the first posttreatment visit (p < 0.001). Microbiologic cures or improvement were observed in 59 of the 65 patients treated with clindamycin (91 percent) compared with 20 of 69 placebo-treated patients (29 percent) (p < 0.001). At the end of the study, clinical and microbiologic cures or improvement were evident in 45 of 57 (79 percent) and 37 of 57 clindamycin-treated patients (65 percent), respectively, and 18 of 51 (35 percent) and 14 of 51 (28 percent) of the placebo-treated patients, respectively. The success rates with clindamycin 2% cream were statistically higher than those with placebo. The adverse-effect profiles in the two groups were similar and no serious adverse effects were reported. Patients who received clindamycin had a statistically higher incidence of nonbacterial vaginitis/cervicitis (18.5 vs. 7.5 percent, p = 0.003).

CONCLUSIONS

Intravaginal clindamycin 2% cream appears to be an effective and safe treatment of symptomatic bacterial vaginosis in nonpregnant women.

Placebo-controlled trial of itraconazole for treatment of acute vaginal candidiasis

Itraconazole is a new orally active triazole antifungal agent with enhanced activity against Candida species. In the clinical trial described in this paper, we compared the efficacy and safety of itraconazole capsules with those of clotrimazole vaginal tablets and placebo oral capsules for women with acute vulvovaginal candidiasis. Ninety-five patients were randomized in a 2:1:1 fashion to receive itraconazole (200 mg/day), clotrimazole (200 mg/day), or placebo (two capsules per day) for 3 consecutive days. Clinical success rates (cure and improvement) were similar for women who received itraconazole (96%) and clotrimazole (100%) 1 week posttreatment. These response rates were statistically superior to those obtained with placebo treatment (77%, P < 0.05). Negative mycological cultures were found in 95, 73, and 32% of the patients treated with clotrimazole, itraconazole, and placebo, respectively (P < 0.005) [active treatments versus placebo]). By 4 weeks posttreatment, the clinical failure rate for itraconazole was less than that observed for clotrimazole (17 versus 30%), but this difference did not reach statistical significance (P > 0.05; beta = 0.81). Mycological response rates for itraconazole and clotrimazole were also similar. No patients enrolled in this study discontinued treatment because of an adverse event. Minor side effects were reported by 35, 4, and 41% of patients who received itraconazole, clotrimazole, and placebo, respectively. The most common side effects associated with itraconazole therapy were nausea and headache. In summary, itraconazole was found to be as effective and safe as clotrimazole in women with acute candida vaginitis. Moreover, oral therapy was highly favored over intravaginal treatment in our survey of patients.

Pharmacokinetic evaluation of enrofloxacin administered orally to healthy dogs

Enrofloxacin was administered orally to 6 healthy dogs at dosages of approximately 2.75, 5.5, and 11 mg/kg of body weight, every 12 hours for 4 days, with a 4-week interval between dosage regimens. Serum and tissue cage fluid (TCF) concentrations of enrofloxacin were measured after the first and seventh treatments. The mean peak serum concentration occurred between 1 and 2.5 hours after dosing. Peak serum concentrations increased with increases in dosage. For each dosage regimen, there was an accumulation of enrofloxacin between the first and seventh treatment, as demonstrated by a significant (P = 0.001) increase in peak serum concentrations. The serum elimination half-life increased from 3.39 hours for the 2.75 mg/kg dosage to 4.94 hours for the 11 mg/kg dosage. Enrofloxacin accumulated slowly into TCF, with peak concentrations being approximately 58% of those of serum. The time of peak TCF concentrations occurred between 3.8 hours and 5.9 hours after drug administration, depending on the dosage and whether it was after single or multiple administrations. Compared with serum concentrations (area under the curve TCF/area under the curve serum), the percentage of enrofloxacin penetration into TCF was 85% at a dosage of 2.75 mg/kg, 83% at a dosage of 5.5 mg/kg, and 88% at a dosage of 11 mg/kg. All 3 dosage regimens of enrofloxacin induced continuous serum and TCF concentrations greater than the minimal concentration required to inhibit 90% (MIC90) of the aerobic and facultative anaerobic clinical isolates tested, except Pseudomonas aeruginosa.(ABSTRACT TRUNCATED AT 250 WORDS)

Pharmacokinetic evaluation of ceftiofur in serum, tissue chamber fluid and bronchial secretions from healthy beef-bred calves

Ceftiofur is a new broad spectrum cephalosporin marketed for the treatment of acute bovine respiratory disease. In this investigation ceftiofur was administered by intramuscular injection, at 24 h intervals, to healthy beef-bred calves for four days at dosages of 2.2 and 4.4 mg/kg of body weight, with 4 wk intervals between dosing regimens. Serum, tissue chamber fluid (TCF), and bronchial secretion (BS) concentrations of ceftiofur were measured by microbiological assay after the first and fourth dose of each dosing regimen. Peak serum concentrations (Cmax) of 8.8 micrograms/mL and 17.3 micrograms/mL were obtained approximately 2 h (Tmax), the time of mean peak concentration) after single injections of 2.2 mg/kg and 4.4 mg/kg, respectively. The Cmax was increased approximately twofold following multiple doses of 2.2 mg/kg (Cmax = 13.1 micrograms/mL) and 4.4 mg/kg (Cmax = 24.1 micrograms/mL). Ceftiofur accumulated slowly into TCF and peak concentrations were found to be approximately 14% of those observed in serum after the first dose and approximately 24% after multiple dosing. Concentrations of ceftiofur in BS were obtained rapidly with peak concentrations reaching 45% of the serum Cmax after the first dose. After multiple dosing the Cmax for BS was approximately 25% of the serum Cmax. This study found that both the 2.2 mg/kg and 4.4 mg/kg dosing regimens resulted in continuous serum, TCF and BS concentrations of ceftiofur that exceeded the minimal concentration required to inhibit the bacteria most frequently isolated from calves with acute bovine respiratory disease.

The new macrolide antibiotics. Azithromycin and clarithromycin

Azithromycin (Zithromax) and clarithromycin (Biaxin Filmtabs) are new macrolide antibiotics with several advantages over erythromycin. Azithromycin has an expanded spectrum against gram-negative bacilli. Clarithromycin is more active than erythromycin against gram-positive cocci; combination with its 14-hydroxy metabolite enhances its antimicrobial activity. These new agents penetrate well into tissues and concentrate in macrophages and polymorphonuclear leukocytes. They offer improved bioavailability and an extended half-life. The high tissue-to-serum level and extended elimination half-life of azithromycin allow for once-daily dosing and short-course therapy. Clarithromycin and 14-hydroxyclarithromycin maintain high serum levels and tissue-to-serum concentrations. Both of these new agents have been effective in streptococcal pharyngitis, acute sinusitis, acute lower respiratory tract infections, skin and soft-tissue infections, and sexually transmitted diseases. A single dose of azithromycin is effective for genital chlamydial infections. Adverse reactions to these agents have usually been mild and have not included serious organ toxicity. In clinical trials, the rate of premature discontinuation of therapy has been less than observed with erythromycin. Azithromycin and clarithromycin should be used according to the current guidelines of the Food and Drug Administration; their future role will be determined by ongoing laboratory and clinical evaluations.

Drug interactions with fluoroquinolones

The fluoroquinolones are a new class of antimicrobial agents that are now widely prescribed for a number of bacterial infections. Because of their complex pharmacokinetics, there is a potential for several types of drug interactions. Currently, only two drug interactions have been well studied. These involve a decrease in absorption when fluoroquinolones are given in combination with multivalent metal cations and an inhibition in the metabolism of methylxanthines by fluoroquinolones such as ciprofloxacin, enoxacin, and norfloxacin. These drug interactions can be easily avoided. Significant decreases in the absorption of fluoroquinolones by metal cations can be prevented by staggering the doses of these drugs. To avoid alterations in methylxanthine metabolism, newer fluoroquinolones, such as lomefloxacin, ofloxacin, and temafloxacin, should be utilized; alternatively, theophylline serum levels can be carefully monitored. Several other potentially serious drug interactions involving cyclosporine, warfarin, and nonsteroidal anti-inflammatory drugs have been reported, but additional investigations are required before their overall clinical significance can be fully determined. Since the use of fluoroquinolones will continue to escalate over the next decade, continued patient surveillance is necessary so that potential drug interactions can be recognized, described, and prevented.

Use of rDNA restriction fragment length polymorphisms to differentiate strains of Candida albicans in women with vulvovaginal candidiasis

Epidemiologic studies in women with recurrent Candida vaginitis have been hampered in the past by the lack of a reproducible typing system. Several molecular probes have now been developed that have the ability to differentiate strains of Candida albicans and give reproducible results. In this investigation, 24 women with Candida vaginitis were studied in a longitudinal fashion for 30 days following short-course antifungal therapy. Seven women with either recurrent vaginitis or with multiple culture-positive sites with C. albicans were included in an epidemiological study. A total of 18 isolates of C. albicans (12 vaginal and six rectal) were typed utilizing restriction fragment length polymorphisms of rDNA. This technique was able to differentiate five different strains of C. albicans. Our epidemiologic study revealed that vaginal and rectal strains recovered from the same women were usually different. None of our patients had a similar vaginal and rectal strain prior to treatment, and only one patient had the same strain isolated from both the rectum and the vagina at the time of recurrence. On the other hand, we found that the same strain of C. albicans was initially and later recovered from the vagina in four of five women who failed treatment or developed recurrent vaginitis. These results suggest that recurrent episodes of C. albicans vaginitis, following short-course antifungal therapy, are often due to relapse of the original infecting strain and not due to autoinoculation from the rectum.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparative study of clarithromycin and penicillin V in the treatment of streptococcal pharyngitis

This study evaluated the safety and efficacy of clarithromycin in the treatment of patients with Group A beta-hemolytic streptococcal pharyngitis. Subjects were treated with either 250 mg clarithromycin twice daily or 250 mg penicillin V four times a day for 10 days and followed for approximately three weeks post-treatment. At the completion of therapy, 96% (45/47) of patients treated with clarithromycin and 89% (43/48) of patients treated with penicillin V were clinically cured or improved. Recurrence of symptoms occurred in 7 and 5 patients who were treated with clarithromycin and penicillin V respectively. Initial bacteriologic eradication was observed in all but one patient. Recurrence of Streptococcus pyogenes occurred in 5 (11%) patients who received clarithromycin and 7 (15%) patients who received penicillin V. The majority of adverse events reported during this study were mild and involved the gastrointestinal tract. Diarrhea was more frequent in patients who received clarithromycin. In this multicenter, randomized, double-blind trial, clarithromycin was as safe and effective as penicillin V in the treatment of Streptococcus pyogenes throat infections.

Comparative study of fluconazole and clotrimazole in the treatment of vulvovaginal candidiasis

Fluconazole is a new oral triazole antifungal with good activity against Candida spp. In this study, we investigated the effectiveness and tolerability of a three-day course of treatment with fluconazole compared with clotrimazole vaginal tablets in nonpregnant women with acute Candida vaginitis. Of the 90 evaluable patients who received fluconazole, 76 (84 percent) were asymptomatic seven to ten days after treatment compared with 84 of 95 (88 percent) treated with clotrimazole. An additional ten patients in the fluconazole group (11 percent) and seven in the clotrimazole group (7 percent) had improvement in their signs and symptoms. Only four patients in each group (4 percent) were considered treatment failures. Mycological cures were obtained in 89 and 93 percent of patients treated with fluconazole and clotrimazole, respectively, seven to ten days posttreatment. Clinical cure rates remained high one month posttreatment: 79 percent in the fluconazole group and 83 percent in the clotrimazole group. Both therapies were well tolerated. One patient discontinued treatment after she developed diarrhea while receiving fluconazole. The most common adverse effects associated with fluconazole use were nausea (six percent) and diarrhea (three percent). No clinically significant laboratory abnormalities were observed. In this investigation, oral fluconazole therapy was found to be as safe and effective as clotrimazole vaginal tablets in women with acute vulvovaginal candidiasis.

Patient costs for prophylaxis and treatment of obstetric and gynecologic surgical infections

The use of newer broad-spectrum antimicrobials for prophylaxis and treatment in obstetric and gynecologic surgery can reduce patient morbidity and hospital costs. For prophylaxis, a single dose of a cephalosporin with a long elimination half-life can be as effective as a more prolonged course. Single-dose prophylaxis reduces not only toxicity and cost to the patient but also the likelihood of colonization of the vagina by resistant organisms. Treatment regimens for postoperative pelvic infections should have broad-spectrum coverage against aerobic and anaerobic pathogens to ensure high cure rates and prevent subsequent abscess formation. With the introduction of newer cephalosporins and penicillin combinations that include a beta-lactamase inhibitor, it is now possible to treat these polymicrobial infections effectively with monotherapy. Compared with traditional antibiotic combinations, these drugs can reduce side effects and the costs of drug administration as well as the need for therapeutic monitoring. The use of oral antibiotics to complete a course of treatment can also help decrease the high costs of parenteral antibiotic therapy and hospitalization.

Treatment of acute uncomplicated urinary tract infection with ceftibuten

Ceftibuten is an orally active third generation cephalosporin with increased potency against members of the Enterobacteriaceae. In this study, 74 women with acute uncomplicated urinary tract infection (UTI) were enrolled in an open study to evaluate the safety and efficacy of this new antibiotic. Patients were treated with 400 mg ceftibuten once daily for seven days and followed for four to six weeks after cessation of therapy. All pathogens were eradicated during treatment, including five coagulase-negative staphylococci that were resistant to ceftibuten. At five to nine days posttreatment, 93% of patients were cured. Of the five recurrent infections, four patients had a relapse and one had a reinfection. By four to six weeks posttreatment, five additional patients had recurrent infections. The overall cure rate was 85% in this study. Most ceftibuten-associated adverse effects were mild and involved the gastrointestinal tract. Diarrhea was the most commonly reported side effect. Of the eight (11%) patients who developed diarrhea, three had a positive latex agglutination test for Clostridium difficile. The diarrhea resolved in all patients without sequelae. Ceftibuten was effective and generally safe in the treatment of women with acute uncomplicated UTI. The high incidence of diarrhea observed in this study is a concern.

Bioavailability and pharmacokinetics of oral ofloxacin formulations in normal subjects

The relative bioavailability and pharmacokinetics of ofloxacin tablets and a reference oral solution of ofloxacin were compared in 32 normal male subjects using a randomized two-way crossover design. After an overnight fast, subjects were randomized to receive a single 200 mg or 300 mg dose of ofloxacin (tablet or solution) and blood samples were obtained prior to and 0.5, 1, 1.5, 2, 3, 4, 6, 8, 12, 16, 24, 36, 48, 72, 96, and 120 hours after the dose. After a 5-day wash-out period, subjects were administered the same dose but of the other formulation, and blood samples were collected in an identical manner. Plasma concentrations of ofloxacin were determined by high-pressure liquid chromatography. The results showed that ofloxacin tablets were more slowly absorbed when compared to the solution and mean peak plasma concentrations were obtained in about 1.5 hours for the tablet preparation. Maximum plasma concentrations were higher after administration of the solution (Cmax = 2.24 micrograms/ml, 200 mg; Cmax = 3.25 micrograms/ml, 300 mg) compared to the tablet (Cmax = 1.74 micrograms/ml, 200 mg; 2.61 micrograms/ml, 300 mg). The bioavailability of ofloxacin tablets was greater than 98% compared to the solution. The other pharmacokinetic parameters were similar between the two dosage formulations. Ofloxacin tablets revealed an apparent volume of distribution of 1.5 l/kg, an elimination half-life of 5.6 hours, and a total clearance of 251 ml/min. In addition, a linear increase in plasma concentrations was observed when the dose of ofloxacin was increased. In summary, ofloxacin tablets was found to be reliably bioavailable and bioequivalent to the reference solution.

Serum and tissue cage fluid concentrations of ciprofloxacin after oral administration of the drug to healthy dogs

Ciprofloxacin, a fluoroquinolone antimicrobial agent, was administered orally to 4 healthy dogs at dosage of approximately 11 and 23 mg/kg of body weight, every 12 hours for 4 days, with a 4-week interval between dosing regimens. Serum and tissue cage fluid (TCF) concentrations of ciprofloxacin were measured after the first and seventh dose of each dosing regimen. The peak concentration was greatest in the serum after multiple doses of 23 mg/kg (mean +/- SEM; 5.68 +/- 0.54 micrograms/ml) and least in the TCF after a single dose of 11 mg/kg (0.43 +/- 0.54 micrograms/ml). The time to peak concentration was not influenced by multiple dosing or drug dose, but was longer for TCF (6.41 +/- 0.52 hour) than for serum (1.53 +/- 0.52 hour). Accumulation of ciprofloxacin was reflected by the area under the concentration curve from 0 to 12 hours after administration (AUC0----12). The AUC0----12 was greatest in the serum after multiple doses of 23 mg/kg (31.95 +/- 1.90 micrograms.h/ml) and least in the TCF after a single dose of 11 mg/kg (3.87 +/- 1.90 micrograms.h/ml). The elimination half-life was not influenced by multiple dosing or dose concentration, but was greater for TCF (14.59 +/- 1.91 hours) than for serum (5.14 +/- 1.91 hours). The percentage of TCF penetration (AUCTCF/AUCserum) was greater after multiple doses (95.76 +/- 6.79%) than after a single dose (55.55 +/- 6.79%) and was not different between doses of 11 and 23 mg/kg. Both dosing regimens of ciprofloxacin resulted in continuous serum and TCF concentrations greater than 90% of the minimal inhibitory concentration for the aerobic and facultative anaerobic clinical isolates tested, including Pseudomonas aeruginosa.

The extended-spectrum penicillins: microbiologic, utilization, and cost review in a community hospital

The extended-spectrum penicillins have a similar spectrum of activity and clinical efficacy. The newer acylaminopenicillins (azlocillin, mezlocillin, piperacillin) offer several potential therapeutic advantages over the carboxypenicillins (carbenicillin, ticarcillin), but they are more expensive per gram. Literature reviews of these penicillins suggest that individual hospital susceptibility patterns and cost should guide selection of the most appropriate antibiotic for formulary addition. Consequently, the authors performed a microbiologic, utilization, and cost review of these antibiotics in a community hospital. From this hospital and literature review, the authors were able to make the following conclusions: (1) the newer acylaminopenicillins exhibited similar activity against common clinical pathogens and were microbiologically more active than the carboxypenicillins; (2) none of these antibiotics used alone appears adequate for empiric treatment of serious systemic gram-negative bacillary infections; (3) the extended-spectrum penicillins were prescribed in a similar fashion and usually in conjunction with an aminoglycoside; and (4) significant cost savings can be realized when less expensive drugs are used. The authors found only minor differences in microbiologic activity and clinical use among the newer extended-spectrum penicillins. Therefore, they recommend the least expensive drug for routine use in the hospital.

Serum and tissue fluid norfloxacin concentrations after oral administration of the drug to healthy dogs

Norfloxacin, a 4-quinolone antibiotic, was administered orally to 4 healthy dogs at dosages of 11 and 22 mg/kg of body weight, every 12 hours for 4 days, with a 4-week interval between dosing regimens. Serum and tissue cage fluid (TCF) norfloxacin concentrations were measured at 0, 0.5, 1, 1.5, 2, 3, 4, 5, 6, 8, 10, and 12 hours after the first and seventh dose of each dosing regimen. When administered at a dosage of 11 mg/kg, the mean peak serum concentration (Cmax) was 1.0 microgram/ml at 1 hour, the time of mean peak concentration (Tmax) after the first dose. After the seventh dose, the Cmax was 1.4 micrograms/ml at Tmax of 1.5 hours. The Tmax for the TCF concentration was 5 hours, with Cmax of 0.3 microgram/ml and 0.7 microgram/ml after the first and seventh dose, respectively. When administered at a dosage of 22 mg/kg, the serum Tmax was 2 hours after the first dose, with Cmax of 2.8 micrograms/ml. After the seventh dose, the serum Tmax was 1.5 hours, with Cmax of 2.8 micrograms/ml. The Tmax for the TCF concentration was 5 hours after the first and seventh doses, with Cmax of 1.2 micrograms/ml and 1.6 micrograms/ml, respectively. After the seventh dose, the serum elimination half-life was 6.3 hours for a dosage of 11 mg/kg and was 6.7 hours for a dosage of 22 mg/kg. For serum concentration, the area under the curve from 0 to 12 hours (AUC0----12) was 8.77 micrograms.h/ml and 18.27 micrograms.h/ml for dosages of 11 mg/kg and 22 mg/kg, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)