Safety profile of orlistat: results of a prescription-event monitoring study.

INTRODUCTION: Orlistat, the first of a new class of drugs for the treatment of obesity, was launched in the UK in December 1998. The prescribing information recommends that treatment with orlistat should be discontinued after 12 weeks if the patient has not achieved a specified loss of weight. OBJECTIVE: To monitor the safety of orlistat prescribed in the primary care setting in England using prescription-event monitoring (PEM). METHODS: A postmarketing surveillance study using the observational cohort technique of PEM. Patients were identified from dispensed prescriptions issued by primary care physicians for orlistat between December 1998 and November 1999. The outcome data were event reports obtained by sending questionnaires (green forms) to the prescribing doctor at least 6 months after the first prescription for an individual patient. Incidence densities, expressed as number of first reports of an event/1000 patient-months of exposure, were calculated. Significant differences between incidence densities (IDs) for events reported in the 1st month (ID(1)) and months 2 and 3 (ID(2-3)) of exposure were regarded as potential signals. Reasons for stopping orlistat were analysed. Follow-up information was requested for selected events and used to assess the causal association with orlistat. RESULTS: Green forms containing clinically useful information on 16 021 patients (median age 45 years (interquartile range 35-54); 80.1% females) were received. The events reported most frequently during the 1st month of treatment were 'not effective' (639; 4.0% of cohort), diarrhoea (371; 2.3%) and weight loss (230; 1.4%). Twelve clinical adverse events were identified for which ID(1) was significantly greater than ID(2-3). These included non-specific events (e.g. intolerance, malaise/lassitude, unspecified side effects), weight loss and vaginitis/vulvitis. The remaining events were gastrointestinal in nature and included diarrhoea, pain abdomen, flatulence, nausea/vomiting, rectal discharge, faecal incontinence and 'gastrointestinal unspecified' events. A similar pattern of predominately gastrointestinal events was seen for reasons for stopping and suspected adverse drug reactions. Review of selected events for causality revealed 45 events which were assessed as possibly or probably related to orlistat. CONCLUSIONS: This study shows that orlistat is fairly well tolerated. The safety profile of orlistat was similar to the prescribing information and experience reported in the literature.

Observational cohort study to monitor the use and safety of carvedilol in the treatment of heart failure in clinical practice in England--1st interim report.

AIMS: This is an interim report of a prospective observational cohort study to monitor the safety and tolerability of carvedilol in clinical practice when prescribed for heart failure in England. The utilization of carvedilol, management of adverse events in the community and the symptomatic progression of heart failure were examined. It is a non-interventional, observational cohort surveillance study using questionnaires sent to the patients' general practitioners. METHODS: The general practitioners (GPs) of the patients identified by the Prescription Pricing Authority were sent an eligibility questionnaire if the patient had been newly prescribed carvedilol between September 1999 and July 2001. Further questionnaires requesting baseline clinical information about eligible patients (carvedilol indicated for cardiac failure) and subsequent event data were sent to consenting GPs at 12 months. The questionnaires also requested specific information about initiation and supervision of treatment, including severity of heart failure and treatment withdrawal. The data were analyzed by using descriptive statistics. In addition, the incidence densities (ID) of each event (per 1000 person-months of treatment) were calculated, ranked and the difference between the ID of each event in the first (ID1) and subsequent 5 months of exposure (ID2) was tested by constructing 99% confidence intervals (CI). Selected events of clinical interest would be followed-up for further information to enable causal association with carvedilol to be assessed. RESULTS: In this interim report we have data on a cohort of 847 eligible patients for whom we have received information from the first follow-up questionnaire. The treatment of carvedilol was initiated in a majority of cases by hospital specialists (87%, n = 735), however, for most of them, further supervision of treatment was done under shared care between GPs and hospitals (70%, n = 595). More than 90% of the patients were started on carvedilol in the recommended dose range for the management of cardiac failure. Amongst the patients where NYHA grade of cardiac failure was expressed, the majority of patients treated with carvedilol had NYHA II (37%, n = 281) and III (40%, n = 297) symptoms at the start of carvedilol treatment. On treatment with carvedilol, improvement in NYHA status was reported for 43% (n = 364) of this cohort, whilst less than 2.5% (n = 20) of the patients deteriorated. The events reported with the highest ID1 were malaise/lassitude (14.6), dizziness (12.2), cardiac failure (9.7), dyspnea (9.7) and hypotension (8.5). The most common events reported as reasons for stopping carvedilol were "drug not effective", "dyspnea", "dizziness" and "lassitude". No events were identified as new signals (according to the ID1-ID2 statistic) of adverse events associated with carvedilol. There have been no events identified in this cohort that have required specific follow-up at the time of writing this paper. CONCLUSIONS: In summary, the interim results show that there is effective cooperation between hospital specialists and GPs in the use of carvedilol in the management of patients with heart failure. It also shows that carvedilol was well-tolerated and that patients with mild and moderate heart failure benefit symptomatically when treated with carvedilol in routine clinical practice.

Evaluation of the safety of fexofenadine from experience gained in general practice use in England in 1997.

BACKGROUND: Fexofenadine is the active metabolite of the non-sedating anti-histamine terfenadine. Pre-licensing clinical trials in over 6000 patients suggested it was effective and well tolerated. OBJECTIVE: To assess the tolerability and safety of fexofenadine immediately after its availability on the UK market in March 1997. METHODS: Post-marketing non-interventional observational cohort study using the methodology of prescription-event monitoring. Exposure data derived from dispensed prescription details supplied in confidence by the Prescription Pricing Authority. Outcome data derived from questionnaires returned by general practitioners (GPs) in England between March and August 1997. RESULTS: Of the 35,817 questionnaires sent, 18,238 (50.9%) were returned, of which 16,638 contained useful data. These included 40% male (mean age 36+/-19 years) and 59% female (mean age 39+/-19 years). Most common indications were allergic rhinitis (55%), not specified (28%), urticaria, pruritus or rash (10%) and other indications (7%). There were 40 reports of adverse drug reactions in 27 patients. Less than 2% of patients stopped the drug because of side effects. Events reported after exposure to fexofenadine were uncommon and already reported in clinical trials. There were eight reports of possible cardiac side effects (palpitations, three; chest pain, three; arrhythmia, one; and chest tightness, one). None was felt to be serious. There were no drug interactions reported. None of the 30 deaths was related to fexofenadine. None of the three adverse outcomes from the 47 pregnancies reported was related to fexofenadine. CONCLUSION: Within the limitations for an observational cohort study, fexofenadine was found to be well tolerated and safe in 16,638 users in general practice in England.