Biomedical subjects

Mark H Gotfried

Publications and source records attributed to Mark H Gotfried.

8 recordsLinked to original sources

PubMed2006

Serum, tissue and body fluid concentrations of tigecycline after a single 100 mg dose.

OBJECTIVES: The purpose of this study was to determine the tissue and corresponding serum concentration of tigecycline at selected time points in gall bladder, bile, colon, bone, synovial fluid (SF), lung and CSF in subjects undergoing surgical or medical procedures. METHODS: One hundred and four adult subjects (aged 24-83 years; 64 women, 40 men) received a single intravenous (i.v.) dose of tigecycline (100 mg infused over 30 min). Subjects were randomly assigned to one of four collection times at 4, 8, 12 and 24 h after the start of the infusion. For CSF, samples were collected at approximately 1.5 and 24 h after the start of the infusion. All subjects had serum samples collected before the administration of tigecycline, at the end of the infusion and at the time corresponding to tissue or body fluid collection. Drug concentrations in serum, tissues and body fluids were determined by LC/MS/MS. The area under the mean concentration-time curve from 0 to 24 h (AUC(0-24)) was determined for the comparison of systemic exposure between tissue or body fluid to serum. RESULTS: The mean serum concentrations of tigecycline were similar to those previously published. Tissue penetration, expressed as the ratio of AUC(0-24) in tissue or body fluid to serum, was 537 for bile, 23 for gall bladder, 2.6 for colon, 2.0 for lung, 0.41 for bone, 0.31 for SF and 0.11 for CSF. CONCLUSIONS: A single 100 mg dose of intravenous tigecycline produced considerably higher tissue/fluid concentrations in bile, gall bladder, colon and lung compared with simultaneous serum concentrations. On average, the systemic exposure of tigecycline in bone, SF and CSF ranged from 11% to 41% of serum concentrations. The results in bone are inconsistent with previous radiolabelled studies in animals and it is unclear if tight binding to bone (versus low bone uptake) or poor extraction of tigecycline for LC/MS/MS detection or both may have contributed to the differences we observed in humans.

Adult↗

PubMed2004

Appropriate outpatient macrolide use in community-acquired pneumonia.

PURPOSE: To review current guidelines concerning the outpatient management of community-acquired pneumonia (CAP), to discuss antibiotic resistance and its relation to outcomes, and to define the appropriate use of newer macrolides in CAP. DATA SOURCES: Comprehensive review of the scientific literature, comparison of published clinical practice guidelines, and expert opinion. CONCLUSIONS: Despite increasing knowledge regarding its etiology and pathogenesis, CAP remains the seventh leading cause of death in the United States. Although 80% of all patients with CAP are treated as outpatients, over 1 million hospital admissions due to CAP occur each year. From an employer perspective, total annual employer costs were fivefold greater for patients with pneumonia than for those who were not affected. Appropriate antimicrobial choices should lead to improved outcomes. Reports of increasing resistance of pathogens associated with CAP, increasing frequency of atypical pathogens, and the availability of an increasing number of antimicrobials have made treatment decisions more involved. IMPLICATIONS FOR PRACTICE: In an effort to improve outcomes, several guidelines have been published recommending appropriate antimicrobial agents to treat CAP in different patient populations. All guidelines base treatment recommendations on the hospitalization status of the patient, and all agree that coverage of atypical pathogens as part of an initial empirical regimen is important. Comorbidity and modifying factors that may increase the risk of infection with resistant organisms also are taken into account. Controversy exists regarding the use of newer macrolides versus newer fluoroquinolones as initial empirical therapy. The applicability of the reported increasing resistance of common pneumonia pathogens to outcomes in regimens containing newer macrolides is a subject of debate. Defining appropriate antimicrobial use in different patient groups should help achieve better outcomes and allay the development of resistance.

Ambulatory Care↗

PubMed2004

Pharmacokinetics and pharmacodynamics of intravenous levofloxacin at 750 milligrams and various doses of metronidazole in healthy adult subjects.

The purpose of this investigation was to evaluate the steady-state pharmacokinetics, pharmacodynamics, and safety of intravenous levofloxacin at 750 mg administered once daily combined with three different dosages of intravenous metronidazole (500 mg every 8 h [q8h], 1,000 mg q24h, and 1,500 mg q24h). Eighteen healthy adult subjects received all three combinations in a randomized, crossover fashion. Serial blood and urine samples were collected on the third day of each study period. The 24-h areas under the inhibitory (AUIC(0-24)) and bactericidal (AUBC(0-24)) curves of these three combination regimens were determined against clinical isolates of Bacteroides fragilis, Bacteroides thetaiotaomicron, Peptostreptococcus asaccharolyticus, and Escherichia coli. The mean concentrations of levofloxacin were not different between study periods and were similar to those previously published. The mean (+/- standard deviation) areas under the metronidazole plasma concentration-time curve (AUC(0-24)) for 1,500-mg q24h (338 +/- 105 mg.h/liter) and 500-mg q8h (356 +/- 68 mg.h/liter) regimens were not different (P > 0.05), but both were significantly higher than the 1,000-mg q24h AUC(0-24) (P < 0.05, 227 +/- 57 mg.h/liter). Mean (+/- standard deviation) total body clearance and renal clearance values were similar among the 500-mg q8h, 1,000-mg q24, and 1,500-mg q24h regimens (62 +/- 7, 67 +/- 13, and 67 +/- 14 and 11 +/- 3, 12 +/- 2, and 12 +/- 5 ml/min/1.73 m2, respectively). Levofloxacin at 750 mg q24h plus metronidazole at 500 mg q8h or 1,500 mg q24h resulted in similar AUIC(0-24) and AUBC(0-24) values with one exception: the AUIC(0-24) for the 1,500-mg q24h regimen against B. thetaiotamicron was significantly higher (P < 0.05) than those of the other regimens. Overall, the combination of levofloxacin at 750 mg once daily and metronidazole at 500 mg q8h or 1,500 mg q24h appeared to have greater AUIC(0-24) and AUBC(0-24) values than did the 1,000-mg q24h regimen. All combination regimens of levofloxacin and metronidazole were well tolerated, and no serious drug-related adverse effects were reported. The pharmacokinetic, safety, and pharmacodynamic data from our study suggest that a once-daily regimen of intravenous levofloxacin at 750 mg and metronidazole at 1,500 mg warrants further clinical investigation.

Adolescent↗

PubMed2004

Macrolides for the treatment of chronic sinusitis, asthma, and COPD.

In addition to their well-known antimicrobial activity, macrolides possess immunomodulatory properties that may confer beneficial effects to patients with respiratory diseases associated with chronic inflammation. These properties include attenuation of inflammatory responses in the lung, mucoregulatory properties, and effects on bronchial responsiveness. Macrolides increase mucociliary clearance, improve sinusitis symptoms, and decrease nasal secretions and polyp size in patients with sinusitis. They also have been shown to modify the inflammatory response associated with chronic sinusitis. In patients with asthma, macrolides have been reported to reduce airway hyperresponsiveness and improve pulmonary function, and have historically been selected for their "steroid-sparing" effect. Preliminary data from studies of patients with COPD have shown improvements in symptom scores and FEV(1) after macrolide treatment. As biological response modifiers, macrolides have the potential to improve the outcomes of patients with inflammatory airway diseases. Large scale, placebo-controlled clinical trials designed to assess long-term efficacy and safety in these diseases are warranted.

Anti-Bacterial Agents↗

PubMed2003

Steady-state plasma and bronchopulmonary characteristics of clarithromycin extended-release tablets in normal healthy adult subjects.

OBJECTIVES: The steady-state concentrations of clarithromycin in plasma were compared with concomitant concentrations in epithelial lining fluid (ELF) and alveolar macrophages (AM) obtained from intrapulmonary samples during bronchoscopy and bronchoalveolar lavage (BAL). Concentrations of the major metabolite, 14-hydroxyclarithromycin, were also determined in plasma and AM. MATERIALS AND METHODS: Forty-two healthy, non-smoking adult subjects (age: 18-54 years; 19 females, 23 males) received oral clarithromycin extended-release formulation (1000 mg once daily for five consecutive days). Bronchoscopy and BAL were carried out once in each subject at either 3, 6, 9, 12, 24 or 48 h after the last administered dose of clarithromycin. In addition, three subjects who did not take clarithromycin served as controls and underwent bronchoscopy at 0 h. Drug concentrations in plasma, ELF, and AM were determined by high-performance liquid chromatography. RESULTS: Clarithromycin was extensively concentrated in ELF [range of mean (+/-s.d.) concentrations: 6.38 +/- 3.92 to 11.50 +/- 6.65 mg/L] and AM (127.0 +/- 61.5 to 573.8 +/- 309.3 mg/L) than simultaneous plasma concentration (0.75 +/- 0.31 to 2.22 +/- 0.72 mg/L). The ranges of mean (+/-s.d.) concentrations of 14-hydroxyclarithromycin in plasma and AM were 0.52 +/- 0.29 to 0.80 +/- 0.31 mg/L and 22.1 +/- 13.5 to 49.5 +/- 16.2 mg/L, respectively. CONCLUSIONS: Once-daily dosing of extended-release formulation clarithromycin 1000 mg produced significantly (P < 0.05) higher steady-state concentrations of clarithromycin in ELF (2-14 times) and AM (50-700 times) compared to simultaneous plasma concentrations throughout the 24 h period after drug administration. The 14-hydroxy metabolite of clarithromycin achieved significantly (P < 0.05) higher steady-state concentrations in AM (18-180 times) compared with concurrent plasma concentrations.

Adult↗

PubMed2003

Steady-state plasma and bronchopulmonary concentrations of intravenous levofloxacin and azithromycin in healthy adults.

The purpose of this study was to compare the concentrations of levofloxacin and azithromycin in steady-state plasma, epithelial lining fluid (ELF), and alveolar macrophage (AM) after intravenous administration. Thirty-six healthy, nonsmoking adult subjects were randomized to either intravenous levofloxacin (500 or 750 mg) or azithromycin (500 mg) once daily for five doses. Venipuncture and bronchoscopy with bronchoalveolar lavage were performed in each subject at either 4, 12, or 24 h after the start of the last antibiotic infusion. The mean concentrations of levofloxacin and azithromycin in plasma were similar to those previously published. The dosing regimens of levofloxacin achieved significantly (P < 0.05) higher concentrations in steady-state plasma than azithromycin during the 24 h after drug administration. The respective mean (+/- standard deviation) concentrations at 4, 12, and 24 h in ELF for 500 mg of levofloxacin were 11.01 +/- 4.52, 2.50 +/- 0.97, and 1.24 +/- 0.55 micro g/ml; those for 750 mg of levofloxacin were 12.94 +/- 1.21, 6.04 +/- 0.39, and 1.73 +/- 0.78 micro g/ml; and those for azithromycin were 1.70 +/- 0.74, 1.27 +/- 0.47, and 2.86 +/- 1.75 micro g/ml. The differences in concentrations in ELF among the two levofloxacin groups and azithromycin were significantly (P < 0.05) higher at the 4- and 12-h sampling times. The respective concentrations in AM for 500 mg of levofloxacin were 83.9 +/- 53.2, 18.3 +/- 6.7, and 5.6 +/- 3.2 micro g/ml; those for 750 mg of levofloxacin were 81.7 +/- 37.0, 78.2 +/- 55.4, and 13.3 +/- 6.5 micro g/ml; and those for azithromycin were 650 +/- 259, 669 +/- 311, and 734 +/- 770 micro g/ml. Azithromycin achieved significantly (P < 0.05) higher concentrations in AM than levofloxacin at all sampling times. The concentrations in ELF and AM following intravenous administration of levofloxacin and azithromycin were higher than concentrations in plasma. Further studies are needed to determine the clinical significance of such high intrapulmonary concentrations in patients with respiratory tract infections.

Adult↗

PubMed2003

Clarithromycin (Biaxin) extended-release tablet: a therapeutic review.

Clarithromycin (Biaxin) extended-release tablets, an advanced generation macrolide, were recently introduced into the USA for the treatment of acute exacerbations of chronic bronchitis, community-acquired pneumonia and acute maxillary sinusitis. The reformulation is intended to improve both patient compliance and tolerability. The extended-release tablets allow convenient once-daily dosing (1000 mg). The extended-release formulation has been shown to be equivalent to the immediate-release formulation concerning area under the plasma concentration time curve. In comparative clinical trials for acute exacerbations of chronic bronchitis, community-acquired pneumonia and acute maxillary sinusitis, clarithromycin extended-release tablets were equivalent to the immediate-release formulation concerning clinical efficacy and bacterial eradication, with improved gastrointestinal tolerability. Similar efficacy and gastrointestinal tolerability results were demonstrated in a recent comparative study of clarithromycin extended-release formulation and amoxicillin-clavulanate in patients with acute exacerbations of chronic bronchitis. Clarithromycin extended-release 1000 mg daily has also been shown to be equivalent to levofloxacin 500 mg daily for the treatment of community-acquired pneumonia in a recent study. The macrolide class of antimicrobials, including clarithromycin extended-release, continues to be a safe and efficacious choice for the out-patient management of community-acquired bacterial respiratory tract infections.

Anti-Bacterial Agents↗

PubMed2002

A controlled, double-blind, multicenter study comparing clarithromycin extended-release tablets and levofloxacin tablets in the treatment of community-acquired pneumonia.

BACKGROUND: Macrolides and fluoroquinolones are frequently used for the empiric treatment of community-acquired pneumonia (CAP). OBJECTIVE: The aim of the study was to compare the safety profile and efficacy of clarithromycin extended-release (ER) tablets with those of levofloxacin tablets for the treatment of CAP in ambulatory adult patients. METHODS: In a Phase III, double-blind, randomized, parallel-group, multicenter study, ambulatory adult patients (> or = 18 years) with signs and symptoms of CAP received a 7-day course of treatment with either clarithromycin ER (two 500-mg tablets once daily) or levofloxacin (two 250-mg tablets once daily). A diagnosis of CAP was confirmed by radiography of the chest and physical examination, and sputum samples were analyzed to identify etiologic pathogen(s). Tolerability was assessed through subjective reports of adverse events and through changes in physical findings, concomitant medications, and laboratory values. RESULTS: There were no statistically significant differences between treatment groups in terms of sex, age, race, or body weight. The mean age was 50 years (range, 18-91 years). Of 299 patients randomized and treated, 252 were clinically evaluable (128 clarithromycin ER, 124 levofloxacin). The 95% CI for the difference between cure rates demonstrated equivalence of the 2 treatments. Among clinically evaluable patients at the test-of-cure visit, clinical cure rates were 88% (113/128) and 86% (107/124), and radiographic success rates were 95% (117/123) and 88% (104/118) for clarithromycin ER and levofloxacin, respectively. Both treatment regimens were effective in resolving and improving clinical signs and symptoms of CAP. Among clinically and bacteriologically evaluable pa- tients, bacteriologic cure rates were 86% (80/93) and 88% (85/97) for clarithromycin ER and levofloxacin, respectively. No statistically significant differences were observed between the 2 treatment groups in the overall incidence of adverse events. CONCLUSIONS: Clarithromycin ER demonstrated equivalent efficacy and tolerability to the fluoroquinolone levofloxacin in a group of ambulatory adult patients with CAP. Clarithromycin ER also appeared to be safe in the population studied.

Adult↗