Clarithromycin-associated digoxin toxicity in the elderly.
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Age Factors↗
Biomedical subjects
D E Griffith
Publications and source records attributed to D E Griffith.
Relationship of adverse events to serum drug levels in patients receiving high-dose azithromycin for mycobacterial lung disease.
We treated 39 elderly human immunodeficiency virus-noninfected patients with Mycobacterium avium complex and/or Mycobacterium abscessus lung disease with azithromycin (600 mg daily), given initially as monotherapy. Adverse events occurred in 33 of 39 patients (85%) receiving azithromycin alone, most commonly gastrointestinal (GI) symptoms (32 of 39, or 82%) and hearing impairment (10 of 39, or 26%). Twenty-four of 39 patients (62%) required a lower dose or withdrawal of the drug. The mean serum level in patients who required a dose reduction because of hearing impairment was 0.8 +/- 0.4 microg/mL, and that in patients whose reduction was necessitated by GI symptoms was 0.7 +/- 0.4 microg/mL; in comparison, the mean serum level was 0.3 +/- 0.16 microg/mL in patients with no adverse events (P = .004 and .003, respectively). Decreasing the daily dose to 300 mg resulted in resolution of most adverse events. Serum levels with monotherapy were comparable to levels after the addition of other antituberculous drugs that included rifampin or rifabutin. Thus, a 300-mg rather than 600-mg daily dose of azithromycin is better tolerated by elderly patients, and serum levels appear unaffected by other antituberculous agents, including rifampin.
Adult↗
Mycobacterium chelonae vs. abscessus.
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Humans↗
Nontuberculous mycobacteria.
The nontuberculous mycobacteria (NTM), especially Mycobacterium avium complex, are being recognized with increasing frequency as clinical pathogens, not only as a cause of disseminated disease in patients with AIDS but also as a cause of chronic lung disease in patients without AIDS. These infections have traditionally been difficult and frustrating to treat; however, the introduction of new agents, such as clarithromycin, azithromycin, and rifabutin, has significantly improved outcome for patients with some NTM infections. The new therapeutic regimens can be associated with severe toxicities and drug interactions that dictate the need for careful monitoring of patients undergoing treatment for M. avium complex disease. Clinicians will be called on with increasing frequency to determine the significance of NTM isolated from their patients. This determination will require knowledge about the pathogenicity and the appropriate therapy of a variety of NTM species.
AIDS-Related Opportunistic Infections↗
Tuberculosis: disease of the past, disease of the present.
Once thought to be under control, tuberculosis is now the number one cause of infection-related death worldwide and the sixth most significant cause of death overall. Transmission occurs by inhalation of airborne droplet nuclei that can be viable for days, and is facilitated by substance abuse, poverty, overcrowding, malnutrition, and, most importantly coinfection with human immunodeficiency virus. This article describes the history and current status of tuberculosis as a growing global health problem, transmission of the disease, risk factors for the general public and health care workers, and prevention of the disease.
Health Personnel↗
Azithromycin activity against Mycobacterium avium complex lung disease in patients who were not infected with human immunodeficiency virus.
We initiated a prospective trial of an azithromycin-containing regimen for the treatment of human immunodeficiency virus-negative patients with Mycobacterium avium complex (MAC) lung disease; the initial 4 months of therapy were with azithromycin (600 mg/d) alone. The primary study endpoint was microbiological response measured at 4 and 6 months of therapy. Of 29 patients enrolled in the study, 23 completed therapy. Fifty-two percent of these 23 patients were male, and 65% were smokers. All 23 patients were older than 45 years of age; 83% had bilateral disease, and 48% had fibrocavitary disease. Macrolide (clarithromycin)-susceptible MAC isolates were recovered from these 23 patients before treatment. Cultures of sputum from 38% of these patients became negative, and the positivity of cultures of sputum from 76% of these patients was significantly reduced. Sixty-eight percent of sputum cultures were strongly positive (> 200 colonies) before therapy, while only 27% were strongly positive after therapy. Although most patients continued to receive 600 mg of azithromycin/d, the high incidence of gastrointestinal side effects (76%) and altered hearing (41%) suggests the need for lower or less frequent dosing. Macrolide (clarithromycin) resistance did not develop in any MAC isolates during monotherapy. These results, which demonstrate that azithromycin is active against MAC pulmonary disease, provide a rationale to include this drug in the initial multidrug regimens recommended for the treatment of this disease.
Aged↗
Varying dosages of rifabutin affect white blood cell and platelet counts in human immunodeficiency virus--negative patients who are receiving multidrug regimens for pulmonary Mycobacterium avium complex disease.
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Azithromycin↗
Differential effects of salmeterol on lung endothelial and epithelial leakage in sheep.
Salmeterol has been shown to prevent the influx of proteins into the air spaces of lungs of guinea pigs given intravenous histamine. To determine whether the salmeterol acts to stabilize the epithelial or endothelial barrier, we ventilated anesthetized sheep with aerosolized salmeterol before infusing histamine intravenously at a rate of 4 micrograms.kg-1.min-1 for 3 h. Changes in endothelial permeability were assessed by measuring the flow of lymph and proteins from the lungs. The influx of proteins into the air spaces was detected by performing single-cycle lavages to measure the concentration of circulating 125I-albumin in the epithelial lining fluid. Intravenous histamine increased the lymph flow to 13.2 +/- 6.8 ml/h compared with the control value of 5.6 +/- 2.8 ml/h (P < 0.05). Histamine also increased the concentration of 125I-albumin in the epithelial lining fluid from 1.8 +/- 0.9 to 8.5 +/- 2.5% of the plasma concentration (P < 0.01) and the postmortem lung water volume from 3.5 +/- 0.5 to 5.0 +/- 0.8 mg/g dry lung wt (P < 0.05). Pretreatment with 2.5 mg of aerosolized salmeterol prevented the influx of proteins into the air spaces and the increase in the postmortem lung water volume but it also increased the lung lymph flow even further to 20.0 +/- 5.6 ml/h (P < 0.05), increased the lymph-to-plasma protein ratio from 0.77 to 0.91, and tripled the increase in alveolar-arterial oxygen gradient caused by histamine alone. Pretreatment with 2.5 mg of intravenous salmeterol had essentially the same effect as salmeterol administered by aerosol. We conclude that salmeterol decreases lung epithelial permeability but increases lung endothelial permeability due to intravenous histamine in sheep.
Albuterol↗
Clarithromycin regimens for pulmonary Mycobacterium avium complex. The first 50 patients.
Intermediate results of the first 50 patients treated with clarithromycin (CLARI) regimens for Mycobacterium avium-intracellulare (MAI) lung disease were evaluated. Patients were HIV negative, and pretreatment isolates were susceptible to CLARI. Patients received CLARI 500 mg twice daily, ethambutol, rifampin (RMP), or rifabutin (RBT) and initial streptomycin, and they were treated until culture-negative 1 yr. Eleven of 50 patients (22%) were dropped in the first 3 mo. Of the remaining 39 patients, 36 (92%) converted their sputa to negative, and 32 (82%) remain culture negative to date. This includes 11 of 16 (69%) with prior drug therapy and 21 of 23 (91%) with no prior therapy. One or more companion drugs were discontinued in 16 of 39 (41%) of patients because of adverse events. Isolates from six of 39 patients (15%) became CLARI-resistant. Of 23 patients who are alive and were culture-negative a mean of 12.0 mo while receiving therapy, all remain culture-negative without therapy a mean of 19.1 mo. Despite reduced CLARI serum levels in patients also receiving RMP, 10 of 13 patients (77%) receiving this regimen were successfully treated. Although not directly compared with previous regimens, the success of this regimen strongly suggests it is superior to previous non-CLARI-containing regimens.
Adolescent↗
New developments in the treatment of nontuberculous mycobacterial (NTM) disease.
Until recently, therapy for most Nontuberculous Mycobacterial (NTM) disease, especially disease caused by Mycobacterium avium-complex (MAC), has been difficult and frustrating. The introduction of the newer macrolides (clarithromycin and azithromycin) has significantly added to the efficacy of regimens for both disseminated and pulmonary MAC disease. Clinical activity of these agents is lost when a MAC isolate develops in-vitro resistance that is facilitated by use of the macrolides as single agents. These valuable drugs should, therefore, never be used as single agents for the treatment of disseminated or pulmonary MAC disease. The newer macrolides also show promise for the treatment of other NTM infections such as those caused by M. abscessus, M. fortuitum, M. chelonae, M. xenopi, M. marinum, M. haemophilum, and M. genavense. Rifabutin, a derivative of rifamycin S, is an effective agent for prophylaxis against disseminated MAC and may have utility for treatment of pulmonary and disseminated MAC disease. Interactions between clarithromycin and rifamycin may alter efficacy of the macrolide and enhance toxicity of rifabutin. Although therapy of many NTM infections remains difficult with somewhat unpredictable results, the introduction of newer drugs, particularly the macrolides, has appreciably improved a previously dismal outlook for successful therapy.
Anti-Bacterial Agents↗
Clarithromycin-induced hepatotoxicity.
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Chemical and Drug Induced Liver Injury↗
Adverse events associated with high-dose rifabutin in macrolide-containing regimens for the treatment of Mycobacterium avium complex lung disease.
We initiated a multidrug trial that included high-dose rifabutin for the treatment of pulmonary Mycobacterium avium complex (MAC) disease. Twenty-six patients received rifabutin (600 mg/d) in combination with ethambutol, streptomycin, and either clarithromycin (500 mg b.i.d.; 15 patients) or azithromycin (600 mg/d; 11 patients). Rifabutin-related adverse events occurred in 77% of patients. Fifty-eight percent of patients required a dosage adjustment or discontinuance of rifabutin therapy. The most common adverse event was a reduction in the mean total white blood cell (WBC) count, which decreased from 8,600 +/- 2,800/mm3 before treatment to 4,500 +/- 2,100/mm3 during treatment (P = .0001). Although all patients had some decrease in WBC count, only three patients (12%) required a dosage adjustment for this reason. Other common adverse events included gastrointestinal symptoms (nausea, vomiting, or diarrhea; 42%) and abnormal liver enzyme levels (12%). Eight of 11 patients (73%) with gastrointestinal symptoms, including one patient with abnormal liver enzyme levels, required a rifabutin-dosage adjustment. The most severe adverse events, always requiring an adjustment of therapy, were a diffuse polyarthralgia syndrome (19%) and anterior uveitis (8%). The latter toxicity has previously been reported to occur only in patients with AIDS and was seen only in patients who also were receiving clarithromycin. On the basis of the current findings, we recommend that rifabutin be used at a dose of 300 mg/d in multidrug regimens that include a macrolide for treatment of MAC lung disease.
Adult↗
Reduced serum levels of clarithromycin in patients treated with multidrug regimens including rifampin or rifabutin for Mycobacterium avium-M. intracellulare infection.
The newer macrolides and rifamycins (rifabutin) are major advances for treatment or prophylaxis of disease due to Mycobacterium avium complex. Although rifampin and rifabutin are known to induce the hepatic cytochrome P-450 system, their impact on the metabolism of clarithromycin is unknown. Clarithromycin and its major metabolite, 14-OH clarithromycin, were measured in the sera of patients receiving 500 mg twice a day before and after the addition of antituberculous drugs, including 600 mg/day of rifampin or rifabutin. Mean serum levels of clarithromycin given as a single agent were 5.4 +/- 2.1 micrograms/mL. These decreased to 0.7 +/- 0.6 micrograms/mL in patients receiving rifampin and 2.0 +/- 1.5 micrograms/mL in those receiving rifabutin. Mean serum levels of 14-OH clarithromycin were similar in the 3 groups (1.8-1.9 micrograms/mL). Rifampin and (to a lesser degree) rifabutin appear to induce the metabolism of clarithromycin.
Clarithromycin↗
Tuberculosis outbreak among healthcare workers in a community hospital.
Twenty-nine healthcare workers (HCW) were exposed to an active case of unrecognized drug-susceptible pulmonary tuberculosis in a community hospital for as long as 2 h in the emergency room and 10 h in a medical intensive care unit. Twelve of the 29 exposed HCW could not be evaluated for tuberculosis infection because 10 of them had a previously positive tuberculin skin test and two were lost to follow-up. Of the remaining 17 tuberculin skin test negative HCW, 13 (76%) either converted their skin test to positive (10 HCW) or developed active disease (three HCW) after exposure to the index case. The Mycobacterium tuberculosis isolates from the three HCW had identical DNA restriction fragment length polymorphism (RFLP) patterns when studied by pulsed field gel electrophoresis. This case of drug-susceptible tuberculosis was associated with unusually high rates of tuberculosis infection and disease in HCW. Prevention of similar occurrences in HCW may be difficult because of the short exposure time required for transmission of tuberculosis and the absence of consensus on optimal respiratory protective measures.
Adult↗
Growth factors for human pleural mesothelial cells in soluble products from formed clots.
Fibrin deposition within the pleural space may influence repair following pleural injury. Although the mesothelial surface can organize fibrin, the contribution of pleural mesothelial cells to pleural repair is unknown. During coagulation thrombin cleaves Fibrinopeptide A (FPA, A alpha 1-16) and fibrinopeptide B (FPB) from the A alpha and B beta chains of fibrinogen to generate fibrin monomer. Since these peptides are mitogenic for human fibroblasts, we considered that they might stimulate replication of human pleural mesothelial cells (HPMC). Application of fluid expressed from fibrin clots significantly increased cell number and stimulated uptake of 3H-thymidine by HPMC compared with untreated cells. The mitogenic response of subconfluent HPMC to dilutions of clot fluid (30-150 micrograms/ml protein) was comparable to that of 0.1 nM TGF-beta. Fibrinopeptide A (7.5-30 microM) stimulated 3H-thymidine uptake in HPMC, but FPB had only a slight effect at 30 microM. Antibody to FPA antibody significantly attenuated the mitogenic effect of clot fluid, indicating that a major component is FPA. Our study suggests that fibrinopeptides released during fibrin formation in vivo may stimulate local mesothelial regeneration following pleural injury.
Catalysis↗
Initial clarithromycin monotherapy for Mycobacterium avium-intracellulare complex lung disease.
Sputum conversion rates in Mycobacterium avium-intracellulare (MAI) complex lung disease have ranged from only 50 to 80% despite the use of three to five antituberculosis agents. We initiated a prospective, open, noncomparative trial of initial clarithromycin monotherapy at 500 mg twice a day for 4 months in HIV-negative patients with MAI lung disease. The primary study end point was microbiologic improvement. Of 30 patients enrolled, 20 completed therapy. This latter group was predominantly male (60%), smokers (70%), older than 45 yr of age (90%), infected with Mycobacterium intracellulare (70%) and with bilateral disease (85%). Of 19 patients with pretreatment minimum inhibitory concentrations (MIC) for clarithromycin < 16 micrograms/ml, 58% became sputum-negative, and 21% showed significant reductions in sputum positivity. Heavily positive sputum cultures (> 200 colonies) were reduced from 30 to 47 samples pretherapy (64%) to three of 54 (6%) post-therapy (p < 0.0001); 18 of 19 patients (95%) showed an improvement in sputum cultures, chest radiographs, or both. Only two patients (7%) discontinued the drug because of adverse events. Only three (16%) of 19 isolates developed clarithromycin resistance (MIC > 32 micrograms/ml). Clarithromycin-susceptible and -resistant MAI isolates from the same patient had identical DNA large-restriction fragment patterns. Clarithromycin is the first single agent to be shown efficacious in the treatment of MAI lung disease.
Adult↗
Interleukin-1-mediated release of interleukin-8 by asbestos-stimulated human pleural mesothelial cells.
The pleuropulmonary response to inhaled asbestos frequently involves inflammation and release of various cytokines from lung cells. Among these, interleukin-8 (IL-8) released from the mesothelium could augment inflammation of the pleura by attracting neutrophils to the pleural space. We used cultures of human pleural mesothelial cells (HPMC) to examine the mechanism of IL-8 production by asbestos and cytokines. Suspensions of amosite, chrysotile, or crocidolite asbestos in concentrations as low as 5 micrograms/ml enhanced release of IL-8 from HPMC during 6 h of incubation at 37 degrees C. Electron microscopy of asbestos-treated HPMC showed that the cells avidly engulfed each of the different types of asbestos fibers. Two proinflammatory cytokines, interleukin-1 alpha (IL-1 alpha) and tumor necrosis factor-alpha, enhanced IL-8 release within 2 h and had an even greater effect after 6 h. Release of IL-8 was measured by an enzyme-linked immunosorbent assay, and functional activity of the cytokine was assessed by chemotaxis of human neutrophils. Identity of IL-8 in HPMC supernatants was established by absorption with an antibody to IL-8. Preincubation of HPMC with IL-1 receptor antagonist (IL-1ra) significantly decreased release of IL-8 after stimulation with amosite or crocidolite asbestos. We conclude that HPMC release IL-8 in response to asbestos stimulation and that the response is, in part, mediated by IL-1, mainly in the form of IL-1 alpha.
Antibodies, Monoclonal↗
Occupational chronic bronchitis: does it mean anything?
A good deal of ambiguity exists surrounding the term chronic obstructive pulmonary disease. Although much information has been uncovered concerning cellular epithelial mechanisms, the inflammatory response, and airflow obstruction, considerable research still needs to be conducted to offer better diagnostic categorization and definition of the role of occupational and environmental agents in the development of obstructive lung disease. This article will review these ambiguities of definition, as well as difficulties in estimating disease prevalence. The pathology of occupational bronchitis as well as occupational etiologic factors, including coal dust, will be reviewed. The significance of airways obstruction as a prognostic factor for future morbidity and its relevance for prevention are discussed.
Bronchitis↗