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Bedaquiline, an antimycobacterial agent approved for drug-resistant tuberculosis, is metabolized by CYP3A4, an hepatic enzyme strongly induced by rifampin, an essential part of drug-sensitive tuberculosis treatment. We examined the pharmacokinetic interactions of bedaquiline plus either rifampin or rifabutin in 33 healthy volunteers. This sub-study of that trial examined the mycobactericidal activity of these drugs against intracellular Mycobacterium tuberculosis using ex vivo whole blood culture. Subjects were randomly assigned to receive two single 400 mg doses of bedaquiline, alone, and, after a 4 week washout period, in combination with steady-state daily dosing of either rifabutin 300 mg or rifampin 600 mg. Blood samples were collected prior to dosing and at multiple time points subsequently, to measure plasma drug concentrations and bactericidal activity in ex vivo M tuberculosis-infected whole blood cultures (WBA). Single oral doses of bedaquiline produced readily detectable WBA ex vivo, reaching a maximal effect of -0.28 log/day, with negative values indicating bacterial killing. Plasma concentrations of 355 ng/ml were sufficient for intracellular mycobacteriostasis. Combined dosing with rifampin or rifabutin produced maximal effects of -0.91 and -0.79 log/d, respectively. However, the activity of the rifabutin combination was sustained throughout the dosing interval, thereby producing a greater cumulative or total effect. At low drug concentrations, rifabutin plus bedaquiline yielded greater mycobactericidal activity than the sum of their separate effects. Neither drug metabolites nor cellular drug accumulation could account for this observation. The combination of rifabutin plus bedaquiline produces sustained intracellular mycobactericidal activity that is greater than the sum of their individual effects. Further studies of the treatment-shortening potential of this combination are warranted.

Allogeneic hematopoietic stem-cell transplant recipients often receive fluconazole or an amphotericin B preparation for antifungal prophylaxis. Because of concerns about fungal resistance with fluconazole and toxicity with amphotericin B, alternative prophylactic regimens have become necessary. To compare the efficacy and safety of intravenous and oral itraconazole with the efficacy and safety of intravenous and oral fluconazole for long-term prophylaxis of fungal infections. Open-label, multicenter, randomized trial. Five transplantation centers in the United States. 140 patients undergoing allogeneic hematopoietic stem-cell transplantation. Itraconazole (200 mg intravenously every 12 hours for 2 days followed by 200 mg intravenously every 24 hours or a 200-mg oral solution every 12 hours) or fluconazole (400 mg intravenously or orally every 24 hours) from day 1 until day 100 after transplantation. Proven invasive or superficial fungal infection, drug-related side effects, mortality from fungal infection, and overall mortality. Proven invasive fungal infections occurred in 6 of 71 itraconazole recipients (9%) and in 17 of 67 fluconazole recipients (25%) during the first 180 days after transplantation (difference, -16 percentage points [95% CI, -29.2 to -4.7 percentage points]; P = 0.01). Superficial fungal infections occurred in 3 of 71 itraconazole recipients (4%) and in 2 of 67 fluconazole recipients (3%). In a multivariable analysis using factors known to affect the risk for invasive fungal infection after hematopoietic stem-cell transplantation, prophylaxis with itraconazole was still associated with fewer invasive fungal infections (odds ratio, 0.300 [CI, 0.111 to 0.814]; P = 0.02) caused by either yeasts or molds. More fungal pathogens were found to be resistant to fluconazole than to itraconazole. Except for more frequent gastrointestinal side effects (nausea, vomiting, diarrhea, or abdominal pain) in patients given itraconazole (24% vs. 9%; difference, 15 percentage points [CI, 2.9 to 27.0 percentage points]; P = 0.02), both itraconazole and fluconazole were well tolerated. The overall mortality rate was similar in each group (32 of 71 patients in the itraconazole group [45%] vs. 28 of 67 patients in the fluconazole group [42%]; difference, 3 percentage points [CI, -13.2 to 19.8 percentage points]; P > 0.2), but fewer deaths were related to fungal infection in patients given itraconazole (6 of 71 [9%]) than in patients given fluconazole (12 of 67 [18%]) (difference, 9 percentage points [CI, -20.6 to 1.8 percentage points]; P = 0.13). Itraconazole is more effective than fluconazole for long-term prophylaxis of invasive fungal infections after allogeneic hematopoietic stem-cell transplantation. Except for gastrointestinal side effects, itraconazole is well tolerated.

Background Cystic Fibrosis (CF) is a life-shortening genetic disease in which ~80% of deaths result from loss of lung function linked to inflammation due to chronic bacterial infection (principally Pseudomonas aeruginosa ). Pulmonary exacerbations (intermittent episodes during which symptoms of lung infection increase and lung function decreases) can cause substantial resource utilization, morbidity, and irreversible loss of lung function. Intravenous antibiotic treatment to reduce exacerbation symptoms is standard management practice. However, no prospective studies have identified an optimal antibiotic treatment duration and this lack of objective data has been identified as an area of concern and interest. Methods We have retrospectively analyzed pulmonary function response data (as forced expiratory volume in one second; FEV 1 ) from a previous blinded controlled CF exacerbation management study of intravenous ceftazidime/tobramycin and meropenem/tobramycin in which spirometry was conducted daily to assess the time course of pulmonary function response. Results Ninety-five patients in the study received antibiotics for at least 4 days and were included in our analyses. Patients received antibiotics for an average of 12.6 days (median = 13, SD = 3.2 days), with a range of 4 to 27 days. No significant differences were observed in mean or median treatment durations as functions of either treatment group or baseline lung disease stage. Average time from initiation of antibiotic treatment to highest observed FEV 1 was 8.7 days (median = 10, SD = 4.0 days), with a range of zero to 19 days. Patients were treated an average of 3.9 days beyond the day of peak FEV 1 (median = 3, SD = 3.8 days), with 89 patients (93.7%) experiencing their peak FEV 1 improvement within 13 days. There were no differences in mean or median times to peak FEV 1 as a function of treatment group, although the magnitude of FEV 1 improvement differed between groups. Conclusions Our results suggest that antibiotic response to exacerbation as assessed by pulmonary function is essentially complete within 2 weeks of treatment initiation and relatively independent of the magnitude of pulmonary function response observed.

Despite its use for decades, pharmacokinetic (PK) and safety studies on colistin are limited. We conducted a phase l, open-label trial to evaluate the safety and PK of multiple doses of intravenous (IV) and aerosolized colistimethate sodium (CMS) administered separately and in combination. In total, 31 healthy adults were enrolled into three cohorts of 9, 10, and 12 participants, respectively. Each cohort received increasing doses of CMS over three dosing periods as follows: Period 1 (IV only), 2.5 mg/kg every 12 h (q12h) to 3.3 mg/kg every 8 h (q8h); Period 2 (aerosolized only), 75 mg 2–4 doses, and Period 3 (combined IV aerosolized), in which was Periods 1 and 2 combined. Safety assessments, serum and lung concentrations of colistin analytes (colistin A, colistin B, CMS A, and CMS B), and kidney biomarkers were measured at specified time points. Increasing the CMS dose from 2.5 mg/kg q12h to q8h resulted in a 33% increase in serum colistin A concentrations from 3.9 μg/mL to 5.3 μg/mL—well above the accepted target of 2 μg/mL for 6 h after dosing, without evidence of nephrotoxicity. However, there was an increase in neurotoxicity, primarily perioral and lingual paresthesias, and self-limited ataxia. IV administration did not increase the lung concentrations of colistin.

When introduced in the 1950s, benzathine penicillin G (BPG) was shown to be effective in eradicating group A beta-hemolytic streptococcus (GAS) for at least 3 weeks after administration. Several studies since the 1990s suggest that at 3-4 weeks serum penicillin G levels are less than adequate (below MIC(90) of 0.016 µg/ml). We studied these levels for 4 weeks after the recommended dose of BPG in military recruits, for whom it is used as prophylaxis against GAS. The 329 subjects (mean age 20 years) each received 1.2 million units BPG IM and gave sera 1 day post injection and twice more at staggered time points over 4 weeks. Serum penicillin G levels were measured by liquid chromatography/tandem mass spectometry. The half-life of serum penicillin G was 4.1 days. By day 11, mean levels were <0.02 µg/ml, and by day 15<0.01 µg/ml. Levels in more than 50% of the subjects were below 0.02 µg/ml on day 9, and <.01 µg/ml on day 16. There was no demonstrable effect of subject body-surface area nor of the four different lots of BPG used. These data indicate that in healthy young adults serum penicillin G levels become less than protective <2½ weeks after injection of 1.2 million units of BPG. The findings require serious consideration in future medical and public health recommendations for treatment and prophylaxis of GAS upper respiratory tract infections.

Cystic fibrosis (CF) is characterized by chronic pulmonary infection with acute pulmonary exacerbations (APEs) requiring IV antibiotic treatment. We report on a blinded comparative trial of IV meropenem (40 mg/kg to 2 g q8h) or ceftazidime (5 mg/kg to 2 g q8h), each of which was administered with IV tobramycin (at a serum peak of ≥ 8 μg/mL and a trough of < 2 μg/mL), as treatment for CF patients with APEs. Patients who were ≥ 5 years of age who were infected with ceftazidime-susceptible Pseudomonas aeruginosa were stratified by lung function and randomized to treatment with meropenem/tobramycin or ceftazidime/tobramycin. Patients infected with Burkholderia cepacia complex or ceftazidime-resistant P aeruginosa were assigned to receive open-label meropenem/tobramycin. Clinical response was assessed by spirometry to determine the change in percent predicted FEV1 and by a clinical acute change score (ACS). One hundred two patients were randomized to meropenem/tobramycin (n = 50) or ceftazidime/tobramycin (n = 52). Nineteen patients received open-label meropenem/tobramycin. FEV1 was improved at the end of treatment (EOT) with meropenem/tobramycin (mean [± SD] increase, 38.8 ± 52.3%) and with ceftazidime/tobramycin (mean increase, 29.4 ± 35.1%; p < 0.0001 vs baseline values). The proportion of patients with ≥ 15% relative increase from baseline FEV1 (satisfactory response) at day 7 was 62% for the meropenem/tobramycin group and 44% for the ceftazidime/tobramycin group (p = 0.04). The median time to FEV1 response was 4 days for meropenem/tobramycin therapy vs 6 days for ceftazidime/tobramycin therapy. Similarly, FEV1 improved in the open-label group (mean increase, 12.5 ± 25.7%; p = 0.05). ACS improved in all three groups at EOT (p < 0.0001 vs baseline values). Therapy with both meropenem/tobramycin and ceftazidime/tobramycin improved pulmonary and clinical status and reduced sputum bacterial burden in CF patients with APEs. A larger proportion of patients receiving meropenem/tobramycin therapy demonstrated a satisfactory FEV1 response at day 7. Resistant P aeruginosa emerged infrequently during treatment with both regimens.

BACKGROUNDThere are no fully oral recommended treatment regimens for gonorrhea. Inadequately treated pharyngeal gonococcal infections are a likely reservoir for transmission and development of antimicrobial resistance. We sought to determine an oral cefixime dosing regimen that would theoretically treat pharyngeal infections by gonococci with minimum inhibitory concentrations 0.5 μg/mL. METHODSWe conducted an open-label, nonrandomized, phase I pharmacokinetic and safety study of cefixime in 25 healthy male and female volunteers divided into 4 dosing cohorts (cohort A, 400 mg; cohort B, 800 mg; cohort C, 1200 mg; and cohort D, 800 mg every 8 hours × 3 doses [total dose 2400 mg]) with a target serum concentration of at least 2.0 μg/mL for more than 20 hours. Cefixime concentrations from serum and pharyngeal fluid were determined with use of a validated liquid chromatography–tandem mass spectrometry assay. Safety measures included laboratories, physical examinations, and symptom diaries. RESULTSNone of the single-dose regimens attained the target concentration; however, 50% of subjects in cohort D attained the target concentration. Variation in absorption and protein binding contributed to differences in concentrations. Pharyngeal fluid concentrations were negligible. The single-dose regimens were well tolerated; the multidose regimen resulted in mild to moderate gastrointestinal symptoms in 43% of subjects. CONCLUSIONSNone of the dosing regimens achieved the target concentration. However, the proposed theoretical target was extrapolated from penicillin data; there are no empirically derived pharmacokinetic/pharmacodynamic criteria for pharyngeal gonorrhea. Under alternative cephalosporin-specific therapeutic goals, the multidose regimen may be effective, although the absence of cefixime in pharyngeal fluid is concerning. A clinical trial evaluating efficacy and defining pharmacokinetic/pharmacodynamic outcomes may be warranted.

In a double-blind, multicenter trial, 541 febrile granulocytopenic patients were randomized to receive either intravenous (iv) clinafloxacin (200 mg every 12 h) or iv imipenem (500 mg every 6 h) as empirical monotherapy. More baseline pathogens were susceptible to clinafloxacin (259 [99%] of 262 organisms) than to imipenem (253 [95%] of 265; P = .03). Initial favorable clinical response rates for clinafloxacin (88 [32%] of 272 patients) and imipenem (89 [33%] of 269) were similar. After addition of other antimicrobial agents, overall response rates were 259 (95%) of 272 for clinafloxacin and 251 (93%) of 269 for imipenem. During the study, only 13 clinafloxacin (5%) and 18 imipenem (7%) recipients died. Both drugs were generally well tolerated. Drug-related skin rash occurred more often with clinafloxacin (11% vs. 6%; P = .07), whereas nausea (2% vs. 5%; P = .16), Clostridium-difficile-associated diarrhea (3% vs. 8%; P = .02), and seizures (0% vs. 2%; P = .06) occurred more often with imipenem. These results suggest that clinafloxacin and imipenem have similar efficacy as empirical monotherapy in febrile granulocytopenic patients.

Objective: The aim of this study was to examine the effectiveness of quetiapine in adolescents suffering from autistic disorder (AD). Methods: This was a 12-week, open-label study, for which medically healthy patients with AD between the ages of 10 and 17 years were eligible. Quetiapine treatment was gradually increased over the first 6 weeks of the study, to a total daily dose of 300 mg/day. Doses could then be increased to a maximum daily dose of 750 mg/day. Outcome measures included the Children's Psychiatric Rating Scale (CPRS) and the Clinical Global Impressions (CGI) scale. Results: Nine (9) males were enrolled. Six (6) patients had previously been treated with other psychotropic agents. Although improvements in several symptom domains were observed on quetiapine, only 2 patients met a priori criteria for response (\"much\" or \"very much improved\" on the Clinical Global Impressions—Improvement Scale). In addition, only these same 2 patients' parents/guardians chose to continue quetiapine pharmacotherapy after study participation. Conclusions: These data suggest that quetiapine may not be a particularly effective agent in the treatment of adolescent patients with AD. However, should future studies be performed, it seems reasonable that they be conducted with more rigor, less treatment-resistant cohorts, and, possibly, a different dosing strategy.

The pharmacokinetic (PK) parameters of lisinopril were obtained in 46 children aged 6 months to 15 years. A lisinopril suspension (0.15 mg/kg per day) was administered to patients <6 years of age; the remaining children received lisinopril tablets, the daily dose being adjusted according to body weight, i.e., 2.5 mg if <25 kg, 5 mg if 25-45 kg, and 10 mg if >45 kg. Blood was drawn predose and on eight occasions postdose in children aged 4-15 years, and on five occasions in those aged <4 years. PK data are reported for the 46 children in terms of age groups: Group I (n=9), aged 6-23 months; Group II (n=8), aged 2-5 years; Group III (n=12), aged 6-11 years; Group IV (n=17), aged 12-15 years. The dose of lisinopril ranged from 3.07 mg/m(2) per day in Group I to 4.78 mg/m(2) per day in Group IV. C(max) of lisinopril, which occurred 5-6 h postdose, varied from 22 ng/ml in Groups I and II to 44 ng/ml in Groups III and IV; AUC(0-24 h) ranged from 301-311 ng.h/ml in Groups I and II to 550-570 ng.h/ml in Groups III and IV. No serious adverse events related to lisinopril were reported.