[A multicenter randomized controlled study of the efficacy and safety of oseltamivir in the treatment of influenza in a high risk population].
ABSTRACT To evaluate the efficacy and safety of oseltamivir in the treatment of influenza in a high risk population.
A randomized, open, control trial was conducted from Nov. 2002 to Feb. 2003. Patients with chronic respiratory disease, such as chronic bronchitis, obstructive emphysema, bronchial asthma, bronchiectasis or chronic cardiac disease, and with symptoms of influenza were enrolled. They should satisfy the following criteria: Fever > or = 37.8 degrees C plus at least two of the following influenza symptoms: coryza/nasal congestion, sore throat, cough, myalgia/muscle aches and pain, fatigue, headache and chills/sweats. Within 48 h after the onset of the symptoms, the patients were randomly assigned to oseltamivir group (oseltamivir 75 mg, twice daily for 5 days) or control group (symptom relief medicine only).
Fifty-six of the 108 recruited patients were identified as influenza-infected through laboratory test. They were defined as intent-to-treat infected population (ITTI) (27 oseltamivir, 29 control). The duration of influenza symptom was 64 h shorter (36.7%) and AUC score of the influenza symptom was decreased by 618 (43.1%) in the oseltamivir group as compared with those in the control group. The fever duration was 46.8 h (45.0%) less in the oseltamivir group than that in the control group. It took 6 d for the oseltamivir group and 11 days for the control group to recover to the basic health status. Secondary complications such as bronchitis, sinusitis and pneumonia occurred 11% (3/27) in the oseltamivir group and 45% (13/29) in the control group. The treatment expense for influenza and its complication was 587.4 RMB in the oseltamivir group and 786.5 RMB in the control group, which showed no significant difference (P = 0.246).
It is suggested that oseltamivir is effective and well tolerated in patients with chronic respiratory or cardiac diseases. It can reduce the fever duration and severity of influenza symptom, and decrease the incidence of secondary complications and antibiotic use, while does not increase the total medical cost.
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ABSTRACT: Pharmacokinetic studies of oseltamivir in very elderly patients (> or = 80 y) have not previously been performed. To compare the pharmacokinetics of oseltamivir and the active carboxylate metabolite in healthy young and very elderly Japanese subjects. Young (20-35 y, fasting, n = 7) and very elderly subjects (> or = 80 y, fed, n = 5) were enrolled in single-center studies and received a single oral dose of oseltamivir 75 mg. Plasma and urine samples were collected (24 h) for pharmacokinetic analysis, and safety was assessed. The time to maximum plasma concentration (tmax) for oseltamivir was delayed in the very elderly compared with the young subjects (2.30 vs 0.71 h, respectively). Furthermore, oseltamivir maximum plasma concentration (Cmax) and AUC(inf) were 52% and 80% higher, respectively, in the very elderly compared with the young subjects. Oral clearance was 45% lower in elderly patients, possibly due to the effects of administration of oseltamivir with a meal. For the active metabolite, oseltamivir carboxylate, Cmax and AUC(inf) values were, respectively, 22% and 91% higher in the very elderly subjects than in the young subjects, while oral clearance was 50% lower in the elderly population. The increased exposure of the active metabolite is likely to correlate with an age-related decline in renal function. For both oseltamivir and the active metabolite, there was large interpatient variability in the Cmax values. The data reported here indicate that oseltamivir would be effective in both of these populations, as trough concentrations for the active metabolite at 12 and 24 hours exceeded the 50% inhibitory concentration against the neuraminidase of influenza A and B isolates by more than 50-fold. Oseltamivir was well tolerated in both groups. Exposures (AUC(inf)) to both the parent drug and active metabolite were increased by more than 80% in the small number of very elderly subjects presented here. However, oseltamivir was well tolerated by these subjects.Annals of Pharmacotherapy 10/2006; 40(10):1724-30. DOI:10.1345/aph.1H174 · 2.92 Impact Factor
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ABSTRACT: Influenza imposes an annual burden on individuals, society, and healthcare systems. This burden is increased by the development of complications that are often more severe than the primary infection. Here, we examine the main complications associated with influenza and review the effectiveness of antiviral therapy in reducing the incidence of such events. The content of this review is taken from the study of the authors' extensive collection of reference materials, examination of the bibliographical content of relevant papers, and the results of Medline searches. The most commonly encountered complications in adults are sinusitis, pharyngitis, bronchitis, and, particularly in the elderly, bacterial pneumonia. Such complications may exacerbate pulmonary complaints. Children are particularly prone to post-influenza croup and otitis media. Complications involving the central nervous system, heart, or skeletal muscle also occur in influenza patients. Influenza-associated complications impose sizeable healthcare costs in terms of outpatient contacts, hospitalizations, and antibiotic use. Vaccination is the primary prevention strategy for influenza and its complications, but has limitations. Neuraminidase inhibitors have demonstrated efficacy in reducing the incidence of influenza-associated complications in populations with different ages and risks. Influenza complications place a large burden on healthcare providers and society. Neuraminidase inhibitors can reduce the incidence of such complications, particularly in high-risk groups.Infection 07/2009; 37(3):186-96. DOI:10.1007/s15010-009-8241-1 · 2.86 Impact Factor
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ABSTRACT: Controversy has arisen regarding the effectiveness of neuraminidase inhibitors (NIs), especially against influenza-related complications. A literature search was performed to critically assess the evidence collected by the available systematic reviews (SRs) regarding the benefits and disadvantages of NIs (oseltamivir, zanamivir) compared to placebos in healthy and at-risk individuals of all ages for prophylaxis and treatment of seasonal influenza. A SR was done using the Cochrane Database of Systematic Reviews, Health Technology Assessment Database, Database of Abstracts of Reviews of Effects, and Medline (January 2006-July 2012). Two reviewers selected SRs based on randomized clinical trials, which were restricted to intention-to-treat results, and they assessed review (AMSTAR) and study quality indicators (GRADE). The SRs included (N = 9) were of high quality. The efficacy of NIs in prophylaxis ranged from 64% (16-85) to 92% (37-99); the absolute risk reduction ranged from 1.2% to 12.1% (GRADE moderate to low). Clinically relevant treatment benefits of NIs were small in healthy adults and children suffering from influenza-like illness (GRADE high to moderate). Oseltamivir reduced antibiotic usage in healthy adults according to one SR, but this was not confirmed by other reviews (GRADE low). Zanamivir showed a preventive effect on antibiotic usage in children (95% (77-99);GRADE moderate) and on the occurrence of bronchitis in at-risk individuals (59% (30-76);GRADE moderate). No evidence was available on the treatment benefits of NIs in elderly and at-risk groups and their effects on hospitalization and mortality. In oseltamivir trials, nausea, vomiting and diarrhea were significant side-effects. For zanamivir trials, no adverse effects have been reported. The combination of diagnostic uncertainty, the risk for virus strain resistance, possible side effects and financial cost outweigh the small benefits of oseltamivir or zanamivir for the prophylaxis and treatment of healthy individuals. No relevant benefits of these NIs on complications in at-risk individuals have been established.PLoS ONE 04/2013; 8(4):e60348. DOI:10.1371/journal.pone.0060348 · 3.53 Impact Factor