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Biomedical subjects

W W Yew

Publications and source records attributed to W W Yew.

At least 37 records · Page 2Linked to original sources
PubMed2001

Therapeutic drug monitoring in antituberculosis chemotherapy: clinical perspectives.

BACKGROUND: Therapeutic drug monitoring (TDM) represents an area where multidisciplinary service is rendered for optimization of clinical care, through enabling maximum drug therapeutic efficacy and minimum drug toxicity. This is a recently developed field for antituberculosis chemotherapy. The other goals of TDM principally include study and management of pharmacokinetic drug-drug and drug-disease interactions as well as the evaluation of new fixed-dose combinations (FDC) developed for treatment of tuberculosis. CONCLUSION: In the years to come, with the advancement in knowledge, technology and expertise, it is hoped that TDM, as a novel paradigm of care in tuberculosis, may gain expanding indications and reach a new horizon.

Antitubercular Agents↗
PubMed2001

Comparison of MB/BacT system and agar proportion method in drug susceptibility testing of Mycobacterium tuberculosis.

The drug susceptibilities of 105 isolates/strains of Mycobacterium tuberculosis (101 clinical isolates and four control strains from the American Type Culture Collection) were assessed by the MB/BacT system and conventional agar proportion method. The agreement rates between the two methods were 99.0% for streptomycin, 95.2% for isoniazid and 100% for rifampin. The mean times to detection for drug-resistant isolates were 4.7 days (range: 2.5-13.7 days) using the MB/BacT system and 14.8 days (range: 14-21 days) using the agar proportion method. For drug-susceptible isolates, the times to detection were 10.8 days (mean) and 21 days respectively. Thus, these data have demonstrated that the automated, non-radiometric MB/BacT system is an efficient, accurate and reliable method for assessing drug susceptibilities of M. tuberculosis compared with the conventional agar proportion method.

Antibiotics, Antitubercular↗
PubMed2001

Postantibiotic effects of antituberculosis agents alone and in combination.

The postantibiotic effects (PAEs) of seven antimycobacterial agents, tested at their respective peak concentrations in serum alone and in different combinations, against Mycobacterium tuberculosis ATCC 27294 were studied with a radiometric culture system in parallel with the viable count method. Rifampin gave the longest PAE (67.8 h) among the drugs used alone, and combinations of first-line drugs generally gave PAEs longer than 120 h. The data obtained might help provide a better understanding of the scientific basis of intermittently administered antituberculosis chemotherapy.

Antitubercular Agents↗
PubMed2001

Chronic necrotizing pulmonary aspergillosis. A report of 9 cases with analysis of clinical picture, risk factors and treatment for outcome correlation.

Nine patients with chronic necrotizing pulmonary aspergillosis (CNPA) were analyzed retrospectively. Eight cases had been treated with itraconazole. Four patients had received intravenous amphotericin B (AMB), three sequentially with itraconazole and one as monotherapy. Three patients died after 1, 2 and 24 weeks of therapy. Six responded to therapy and survived 3 to 58 months after treatment. Only the total number of risk factors was found to be statistically significant in relation to a fatal outcome. The mean number of risk factors was 5.33 for fatal cases compared to 2.83 for treatment responders. The presence of five or more risk factors and two individual risk factors, hypoalbuminemia less than 27 g/L and history of dual pulmonary mycobacterioses, were 100% predictive of mortality in our patients. The overall clinical picture of fatal CNPA cases resembles closely that of acute invasive pulmonary aspergillosis in severely immunocompromised subjects.

Aged↗
PubMed2000

Antituberculosis drug-related liver dysfunction in chronic hepatitis B infection.

Liver toxicity is a common side effect of antituberculosis (anti-TB) drugs. We studied the differences in liver dysfunction observed during anti-TB treatment between hepatitis B virus carriers (HBV) and noncarriers. Three hundred twenty-four patients on anti-TB drugs were recruited and followed up for 1 year. Forty-three patients with HBV and 276 non-HBV patients were included for analysis. Liver function tests and viral markers were monitored monthly. Liver biopsy was requested whenever the alanine transaminase (ALT) was persistently abnormal. Eighty-six HBV carriers who were not given anti-TB drugs were chosen as a second control and evaluated prospectively. The incidence of liver dysfunction was significantly higher in HBV carriers given anti-TB drugs (34.9%) when compared to noncarriers (9.4%, P <.001) and with HBV carriers not given anti-TB drugs (8.1%, P <.001). For patients given anti-TB drugs, HBV carriers who developed liver dysfunction were younger (P =.011) and had more severe liver injury compared with noncarriers (P =.008). By multiple logistic regression analysis, age (P =.002) and hepatitis B infection (P <.001) were the only 2 significant risk factors for hepatotoxicity related to anti-TB therapy.

Adult↗
PubMed2000

Outcomes of patients with multidrug-resistant pulmonary tuberculosis treated with ofloxacin/levofloxacin-containing regimens.

OBJECTIVE: To analyze outcomes of patients with multidrug-resistant tuberculosis (MDR-TB) treated with ofloxacin/levofloxacin-containing regimens. MATERIALS AND METHODS: From February 1990 through June 1997, 63 MDR-TB patients (with bacillary resistance to at least isoniazid and rifampin in vitro) were analyzed retrospectively. Twenty-two patients (34.9%) had had no previous antituberculosis chemotherapy. Each patient received either ofloxacin (53) or levofloxacin (10) even though 13 patients had bacilli resistant to ofloxacin in vitro. The other accompanying drugs mainly included aminoglycosides, cycloserine, ethionamide/prothionamide, and pyrazinamide. Sputum smear and culture examinations for acid-fast bacilli (AFB) were performed monthly for the initial 6 months and then at 2- to 3-month intervals until the end of treatment. Comparison was made between clinical successes and failures using univariate and multiple logistic regression analyses for the following variables: age, sex, presence of cavitation, extent of disease, sputum smear positivity, in vitro resistance to ofloxacin, in vitro resistance to streptomycin and/or ethambutol, treatment adherence, and the number of drugs per regimen. RESULTS: Fifty-one patients (81.0%) were cured, nine patients (14.3%) failed, and three patients (4.7%) died. For the entire group, the mean duration of treatment was 14.0 months, and the mean number of drugs was 4.7. Mean durations of chemotherapy in successful and failed patients were 14.5 and 14.2 months, respectively. Mean time for sputum smear and culture conversions were 1.7 and 2.1 months, respectively. Only cavitation, resistance to ofloxacin, and poor adherence were found to be variables independently associated with adverse outcomes (p < 0.05; odds ratios = 15.9, 13.5, 12.8, respectively). Negative sputum cultures after 2 and 3 months of therapy were 100% predictive of cure. Positive sputum cultures after 2 and 3 months were 52.3% and 84.6% predictive of failure, respectively. One patient (2.1%) relapsed after apparent cure. Twenty-five patients experienced adverse drug reactions, but only 12 of them needed drug modifications. CONCLUSION: Most MDR-TB patients can be treated effectively with ofloxacin/levofloxacin-containing regimens. Presence of cavitation, resistance to ofloxacin in vitro, and poor adherence to therapy portend treatment failure. Monitoring monthly sputum culture for AFB in the initial months of chemotherapy helps predict clinical outcomes.

Adult↗
PubMed1999

Improved recovery of Mycobacterium tuberculosis from pleural aspirates: bedside inoculation, heparinized containers and liquid culture media.

The effects of bedside inoculation, heparinized containers and liquid culture media on the recovery of Mycobacterium tuberculosis from pleural aspirates were evaluated in this study. Of 155 patients, 63 were diagnosed to have pleural effusion tuberculous in origin. The overall recovery of M. tuberculosis was 57.1%. Bedside inoculation of the specimens produced a significantly higher yield than laboratory inoculation using non-heparinized specimens. When the pleural aspirates were transported in heparinized containers, the recovery rate was comparable to that from bedside inoculation, but lower when non-heparinized containers were used. No significant difference was found in recovery rate between the two liquid media, but the rate was significantly higher with the use of liquid media than conventional solid media. Thus, bedside inoculation of pleural aspirates, use of heparinized containers for transport for delayed inoculation in the laboratory and use of liquid culture media are recommended.

Anticoagulants↗
PubMed1999

Directly observed therapy, short-course: the best way to prevent multidrug-resistant tuberculosis.

Adherence to therapy in patients with tuberculosis (TB) is a major determinant of their outcomes. Unfortunately, there are no currently known predictors of adherence, given that this phenomenon represents a complex, task-specific behavior. Notwithstanding criticisms from civil liberty advocates, directly observed therapy (DOT), facilitated by education, holistic care, enablers and incentives, is still the best strategy to ensure patient adherence to treatment. To enhance delivery of DOT, short-course chemotherapy (SCC) must be strongly advocated. Monitoring of patient progress, dependable drug supply, and adequate programme funding are other important elements of the entire strategy. Indeed, since the global resurgence of TB and associated rampant drug resistance in the 1990s, directly observed therapy, short-course (DOTS) has now become the WHO strategy for effective TB control. Data obtained so far in different continents worldwide have underscored the unrivalled efficacy of DOTS in ensuring treatment success and preventing development of acquired drug resistance. The recent WHO/International Union against Tuberculosis and Lung Disease (IUATLD) global project on anti-TB drug resistance surveillance has also revealed that countries in which >33-90% of the population has access to the WHO DOTS strategy have, as a group, lower levels of drug resistance: primary multidrug-resistant (MDR) (1.4%; median) and acquired MDR index (0. 6; median). The use of SCC was also inversely associated with the prevalence of combined resistance to any drug. Countries with MDR rates >2% reported using SCC in a median of 70% of their patients, compared with 100% in countries with MDR rates <2% (WHO/TB/97.229). Despite greater initial cost, DOTS is a more cost-effective strategy than self-administered therapy because it decreases the re-treatment costs associated with therapy failure and acquired drug resistance. Finally, in addition to harnessing the complementary roles of a national tuberculosis programme and community participation, DOTS might be further enhanced by the use of newly developed drugs with a long duration of action or more potent bactericidal and sterilizing activities.

Antitubercular Agents↗
PubMed1999

Report of eight cases of pulmonary actinomycosis and their treatment with imipenem-cilastatin.

Studies on the efficacy of antimicrobial agents against actinomycosis in vivo have been limited apart from those involving penicillin. A prospective ministudy on the efficacy of imipenem-cilastatin in the treatment of pulmonary actinomycosis was performed based on preliminary encouraging in vitro and in vivo data. Eight patients were diagnosed as having pulmonary actinomycosis using fibreoptic bronchoscopy (7) and percutaneous transthoracic needle biopsy (1) in the authors' unit between 1994 and 1996. Each patient received a 4-week course of imipenem-cilastatin that comprised 2 weeks of intravenously administered drug (500 mg at 8-hourly intervals) and 2 weeks of intramuscularly administered drug (500 mg at 12-hourly intervals). Seven patients showed a very good clinical and radiographic response as well as bronchoscopically-documented treatment success. Treatment failed in one patient. Amongst the former group, one patient was lost to follow-up, another relapsed 3 months after treatment cessation and the rest remained relapse-free when followed-up for 18-44 months (mean 30.2 months). Furthermore, all patients showed good clinical tolerance and no abnormal treatment-related laboratory findings. The favourable outcome for most patients in this mini-study suggest that a 4-week parenteral course of imipenem-cilastatin is an efficacious treatment for pulmonary actinomycosis. This antimicrobial regimen might be a promising alternative to the time-honoured long-course treatment with intravenous and oral penicillin.

Actinomycosis↗
PubMed1999

Is inhaled corticosteroid useful as adjunctive management in tuberculous pyrexia?

Systemic corticosteroid is currently the standard adjunctive therapy for tuberculous pyrexia. A preliminary prospective open study to examine the efficacy of inhaled budesonide at a dose of 2,400 micrograms daily in the management of this condition was performed. Out of nine non-HIV infected patients with tuberculous pyrexia studied, four patients succeeded to achieve defervescence at a mean of 3.25 days (range = 2 to 5 days), while the rest of the patients failed to do so within 7 days. None of the patients had unwanted side effects of systemic corticosteroid and patients' acceptance of such therapy was high. The potential usefulness of inhaled corticosteroid in some patients with tuberculous pyrexia might warrant further evaluation.

Administration, Inhalation↗