Use and risk management of carvedilol for the treatment of heart failure in the community in England: results from a modified prescription-event monitoring study.

BACKGROUND: In the UK, the licence for carvedilol was extended in 1998 to include symptomatic heart failure (New York Heart Association [NYHA] class II and III heart failure) with the recommendation that initiation and up-titration should be under the supervision of a hospital physician. A post-marketing surveillance study was conducted to address the UK regulatory authority's request for monitoring the use and safety of carvedilol prescribed for heart failure in clinical practice. AIM: To investigate adherence to risk management recommendations for the use of carvedilol for heart failure, monitor how patients' subsequent care was managed and collect event data to evaluate the safety profile of carvedilol used for the treatment of heart failure. METHODS: An observational cohort study using a modified prescription-event monitoring technique identified patients from dispensed primary care prescriptions in England (August 1999 to June 2001). An eligibility questionnaire was used to identify patients who had been prescribed carvedilol for heart failure for the first time after 31 July 1999. Up to three follow-up questionnaires were sent to the prescribers of eligible patients, requesting demographic information, dosage, supervision of treatment, status of cardiac failure and event information. RESULTS: 2311 patients met the eligibility criteria. For 1666 patients, one or more valid follow-up questionnaires were returned: 68.5% were male; male median age 66 years; female median age 72 years; the observation period was up to 3 years. Hospital physicians supervised initiation of treatment and first up-titration in 85.6% and 61.4% of patients, respectively. 49.2% of patients were prescribed the recommended starting dosage of carvedilol (6.25 mg/day). Approximately 25% of patients started on a lower dose than recommended, and the same proportion were prescribed a higher dose. NYHA status of cardiac failure between starting treatment and the third questionnaire improved for 39.5% of patients, deteriorated for 10.9%, and 11.7% of those for whom NYHA status was given died. Adverse drug reactions (ADRs) were reported for 2.4% of patients; the most commonly reported ADR was malaise/lassitude. Overall, 27.1% of patients stopped taking carvedilol. None of the 163 deaths were attributed to carvedilol. CONCLUSIONS: Regulatory guidelines for the use and risk management of carvedilol in heart failure were mostly followed, and most patients appeared to benefit from treatment with carvedilol for heart failure. Malaise/lassitude was the main reason for discontinuing treatment. Further investigations may be warranted to examine the prescribing of carvedilol at lower than recommended doses.

Safety and drug utilization profile of varenicline as used in general practice in England: interim results from a prescription-event monitoring study.

BACKGROUND: Varenicline tartrate (Champix), a new smoking cessation medicine, was launched in the UK in December 2006. Varenicline is a highly selective partial agonist of the alpha(4)beta(2) nicotinic acetylcholine receptor (alpha(4)beta(2) receptor). The partial agonistic binding leads to alleviation of symptoms of craving and withdrawal, and simultaneously prevents nicotine from binding to the alpha(4)beta(2) receptor thereby causing reduction in the rewarding and reinforcing effects of smoking. Regulatory concerns have arisen about psychiatric events associated with varenicline, including depression, suicidal ideation and changes in behaviour/emotion. AIM: To present the interim results of an ongoing study by the Drug Safety Research Unit (DSRU) monitoring the safety of varenicline. METHODS: The observational cohort study is being conducted to study the postmarketing safety of varenicline, using modified prescription-event monitoring (PEM) methodology. Patients are identified from dispensed prescriptions issued by general practitioners (GPs) from December 2006. Demographic, clinical event (during the course and 1 month after stopping varenicline, reasons for discontinuing and suspected adverse drug reactions [ADRs] to varenicline) and drug utilization data are collected from detailed study-specific questionnaires posted to GPs at least 4 months after the date of first prescription for each patient. Event incidence densities (IDs; number of first reports of an event/1000 patient-months of exposure) are calculated. RESULTS: The interim cohort comprises 2,682 patients: median age 47 years (interquartile range [IQR] 38-56), 60.7% females (n = 1627). Nausea/vomiting was the most frequent clinical reason for stopping varenicline (n = 91; 35.3% of clinical reasons) and the most frequently reported suspected ADR to varenicline (n = 60, 50.9% of patients for whom an ADR was reported). The most frequently reported psychiatric events (causality not implied) during treatment included (n; % of cohort): sleep disorder (43; 1.6%), anxiety (33; 1.2%), depression (29; 1.1%), abnormal dreams (26; 1.0%) and mood change (17; 0.6%). Two cases of attempted suicide were reported during treatment with varenicline (one patient took an overdose of a benzodiazepine with alcohol, the other slashed their wrist). Both these patients had previous history of psychiatric illness and precipitating factors for the event. CONCLUSION: This study reflects 'real life' use of varenicline. Nausea/vomiting - the event most frequently reported as an ADR and as reason for stopping treatment - is listed in the UK Summary of Product Characteristics (SPC). The most frequently reported psychiatric events are listed in the UK SPC. All patients with suicidal events either had a past medical history of psychiatric illness prior to starting varenicline and/or a precipitating factor for the event. Clinicians should closely monitor patients with pre-existing psychiatric illness who are taking varenicline. Further evaluation of events of interest including psychiatric events is ongoing. Results presented are expected to change as the cohort size increases. Results of this study should be taken into account together with other clinical and pharmacoepidemiological studies.

The safety profile of tadalafil as prescribed in general practice in England: results from a prescription-event monitoring study involving 16 129 patients.

OBJECTIVES: To examine the safety of tadalafil as used in general practice in England, and to compare the mortality rate due to ischaemic heart disease (IHD) in tadalafil users with that in the male population in England. PATIENTS AND METHODS: Patients in this observational cohort study were identified from dispensed prescriptions for tadalafil issued by general practitioners (GPs) from February 2003 to November 2004. Demographic and outcome data (clinical events) were requested from patients' GPs using a postal questionnaire. A standardized mortality ratio (SMR) was calculated using indirect standardization for deaths from IHD in the cohort (where age was known) over a 1-year observation period compared to that in the English male population (2003). A sensitivity analysis was carried out to investigate the effects of missing data for age and cause of death. RESULTS: Clinical information was obtained for 16 129 patients (median age 60 years, interquartile range 52-67); the age was not specified for 3212 (19.9%) patients. At least a third of the patients had diabetes mellitus and 29% had hypertension. Comparison of the mortality rate due to IHD for the patients of known age with that in the English male population provided an SMR of 0.57 (95% confidence interval 0.38-0.83) indicating fewer observed deaths in the cohort than expected. The results of the sensitivity analyses investigating the effect of missing data for age and cause of death produced similar SMR estimates. One confirmed case of non-arteritic anterior ischaemic optic neuropathy (NAION) was reported during tadalafil therapy in a patient with other risk factors for this condition. CONCLUSION: The results from this prescription-event monitoring study suggest that tadalafil is generally well tolerated when used in general practice in England. The most frequently reported adverse clinical events were in keeping with clinical trial data and include headache, dyspepsia and back pain. There was no evidence of a greater mortality rate due to IHD in the tadalafil cohort than in the general male population. However, these results are limited by the use of an external comparator group and might be explained by a 'healthy cohort effect'. One event of NAION was reported, and although a causal relationship was not established it indicates that NAION occurs rarely in patients prescribed tadalafil.

Safety profile of esomeprazole: results of a prescription-event monitoring study of 11 595 patients in England.

OBJECTIVE: Esomeprazole, the S-isomer of omeprazole, was launched in the UK in September 2000. The first proton pump inhibitor, omeprazole, has been marketed in the UK for over 10 years. However, the adverse event database of newly marketed drugs is limited, and it is only after widespread clinical use that the adverse effect profile of a drug is ascertained more comprehensively. This study aims to monitor the safety of esomeprazole 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 for esomeprazole issued by general practitioners between September 2000 and April 2001. Questionnaires ('green forms') requesting clinical event data on these patients were sent to prescribers approximately 6 months after the date of the first dispensed prescription for each individual patient. Incidence densities (IDs), expressed as the number of first reports of an event/1000 patient-months of exposure (PME), were calculated. Significant differences between IDs for events reported in the first month (ID1) and the following 5 months (ID2-6) of exposure were regarded as potential signals. Other methods for signal detection such as medical evaluation of selected events and evaluation of reasons for stopping were also applied. RESULTS: Green forms containing clinically useful information for 11 595 patients (median age 56 years; 53.2% female) were received. Diarrhoea was the event with the highest ID1 in month 1 (8.0 per 1000 patient months of exposure). Adverse events that occurred significantly more often in the first month of treatment with esomeprazole compared with months 2-6 included diarrhoea, nausea/vomiting, abdominal pain, dyspepsia, headache/migraine, intolerance, malaise/lassitude, pruritus, unspecified adverse effects and abnormal sensation. CONCLUSIONS: The safety profile of esomeprazole was consistent with the prescribing information and experience reported in the literature.

Monitoring the safety of pioglitazone : results of a prescription-event monitoring study of 12,772 patients in England.

BACKGROUND: Pioglitazone is an antidiabetic drug that targets insulin resistance in patients with type 2 diabetes mellitus by stimulating the peroxisome proliferator-activated receptor (PPAR)-gamma. Pioglitazone belongs to a class of drugs called thiazolidinediones (TZDs) and was launched in the UK in November 2000. OBJECTIVE: To monitor, using prescription-event monitoring, the post-marketing safety of pioglitazone, which is prescribed in primary care in England. METHODS: An observational cohort study in which patients were identified from dispensed prescriptions issued by primary-care physicians/general practitioners (GPs) between November 2000 and June 2001. Information on demographics, the use of pioglitazone, clinical event data, events suspected as adverse drug reactions, reasons for stopping the drug and cause of death (if appropriate) were collected using questionnaires posted to GPs at least 8 months after the date of first prescription for each patient. Event incidence densities (IDs) [number of first reports of an event/1000 patient-months of exposure] were calculated. RESULTS: The cohort comprised 12 772 patients (median age 62 years); 53.1% were males. The most frequent starting daily dose of pioglitazone was either 15 mg or 30 mg (n = 10 298). Pioglitazone/metformin was the most frequently used combination reported (n = 4029). Of the 3690 patients who stopped treatment, 1143 stopped due to reasons related to poor glycaemic control. 'Oedema/fluid retention' (n = 121) and 'weight gain' (n = 118) also appeared high on the list of reasons for discontinuing. 'Malaise/lassitude' and 'nausea/vomiting' were the most frequently reported suspected adverse drug reactions (ADRs) associated with pioglitazone. Specific clinical events considered as early onset events with pioglitazone were: 'malaise/lassitude', 'nausea/vomiting', 'dizziness', 'headache/migraine', 'diarrhoea', 'weight gain' and 'abnormal liver function test'. CONCLUSION: Pioglitazone was considered to be a reasonably well tolerated drug, with the main reasons for discontinuing being related to the drug not being effective. The frequency of individual ADRs reported in this study did not exceed the frequency in the summary of product characteristics (SPC) for pioglitazone. However, amongst the frequently reported suspected ADRs, 'nausea/vomiting' and 'diarrhoea' are not listed in the SPC. Further research is required to assess whether the risk of myocardial infarction and deaths due to cardiovascular causes is a class effect of the thiazolidinediones. Results from this study should be taken into account with other clinical and pharmacoepidemiological studies.

A modified prescription-event monitoring study to assess the introduction of Seretide Evohaler in England: an example of studying risk monitoring in pharmacovigilance.

INTRODUCTION: Monitoring was required for the introduction of non-chlorofluorocarbon (CFC) propellants in metered dose inhalers (MDIs) to ensure that there were no unexpected adverse events due to the new products. A postmarketing surveillance study has been conducted to evaluate the introduction of the MDI Seretide Evohaler (hydrofluoroalkane-134a inhaler containing salmeterol and fluticasone propionate). OBJECTIVES: To summarise the modified prescription-event monitoring (PEM) study conducted to evaluate the introduction of Seretide Evohaler and discuss the relevance of this type of study towards pharmacovigilance risk-management planning. METHODS: Modified PEM methodology was used to examine the introduction of Seretide Evohaler into general practice in England. Patients were identified from the first National Health Service prescriptions dispensed in England for Seretide Evohaler. One postal questionnaire was sent to the prescribing doctor, requesting demographic information, severity of the indication, concomitant medication for this condition, smoking history, event data 3 months prior to and 3 months after the first prescription for Seretide Evohaler and also reason for stopping if it had been stopped. Pregnancies, deaths and selected events were followed up. Incidence density ratios were calculated to compare event rates 3 months prior to and 3 months after the introduction of Seretide Evohaler. A matched cohort analysis examined oral corticosteroid use and hospital admissions between the pre- and post-exposure periods. RESULTS: The cohort comprised 13,464 patients prescribed Seretide Evohaler, with a response rate of 62%. There was no significant difference in the length of courses of oral corticosteroid use when the pre- and post-exposure periods were compared. A matched cohort analysis showed there was no increase in the use of oral corticosteroids (relative risk [RR] 0.95; 95% CI 0.90, 0.99) or hospital admissions in the post-exposure period (RR 0.87; 95% CI 0.73, 1.04). When the number of patients with events were compared for the periods 3 months before and 3 months after exposure, fewer events were reported in the post-exposure period. There were 64 patients who experienced adverse events within an hour of using Seretide Evohaler, including one report of paradoxical bronchospasm and one of myocardial infarction with fatal outcome that were both assessed as possibly related to treatment. DISCUSSION: The results of the study suggest that the introduction of Seretide Evohaler was generally well tolerated. The modified methodology has allowed a comparison of the event rates before and after the introduction of this CFC-free inhaler into general practice.

Safety of zafirlukast: results of a postmarketing surveillance study on 7976 patients in England.

OBJECTIVES: A prescription event monitoring (PEM) postmarketing surveillance study was carried out to examine the safety of zafirlukast as used in general practice in England. METHODS: Exposure data were obtained from the first National Health Service (NHS) prescription dispensed for patients whose prescription details were processed by the Prescription Pricing Authority between August 1998 and December 2000. Outcome data were obtained from 'green form' questionnaires sent to general practitioners (GPs) at least 6 months following the first prescription issued. Incidence densities (IDs) were calculated for events reported per 1000 months of patient exposure and ID differences between the first month of treatment and months 2-6 combined were analysed. Events of medical interest were followed up by postal questionnaire sent to GPs. RESULTS: 21 557 green forms were sent to 8051 doctors, of which 9124 (42.3%) were returned. Useful clinical data was obtained for 7976 patients of which 4664 (58.5%) were female and 3265 (40.9%) were male. The patient's sex was not specified in 47 (0.6%) forms. The median age of the cohort was 53 years (interquartile range 38-66 years). The most frequently reported primary indication was the licensed indication of asthma, but for a small proportion of the cohort it was prescribed 'off label'.A total of 152 events in 120 (1.5%) patients were reported as adverse drug reactions (ADRs) by GPs on the green forms. ADRs with the highest reported frequency were headache and nausea. There were 3514 reasons for stopping zafirlukast in 3148 (39.5%) patients, the most frequently reported of which was that the drug was 'ineffective' (2008 patients; 25.2%). The most frequently reported specified clinical reason for stopping was headache (82 patients; 1.0%). There were 28 pregnancies reported in this cohort, 20 of which were reported to have exposure to zafirlukast during the first trimester. Nine live births with no recorded congenital abnormalities were reported for pregnancies with exposure in the first trimester. There were 151 deaths reported during the study period (1.9%). The most frequently reported causes of death were related to the respiratory system (57; 37.7%), including chronic obstructive pulmonary disease, asthma and bronchopneumonia. CONCLUSION: This study showed that zafirlukast, as used in general practice in England, is a generally well tolerated drug with few associated adverse events.

Safety profile of rosuvastatin: results of a prescription-event monitoring study of 11,680 patients.

BACKGROUND AND OBJECTIVE: Rosuvastatin is a lipid-lowering drug, the newest of a class of drugs called HMG-CoA reductase inhibitors, or 'statins', launched in the UK in March 2003. Our objective was to monitor the post-marketing safety of this drug, prescribed in primary care in England, using prescription-event monitoring. METHODS: An observational cohort study in which patients were identified from dispensed prescriptions issued by primary care physicians/general practitioners (GPs) between August and December 2003. Demographic and clinical-event data were collected from questionnaires posted to GPs at least 6 months after the date of first prescription for each patient. Stratified analysis of specific events by starting dose of rosuvastatin was conducted. Follow-up and causality assessment of medically significant events was undertaken. RESULTS: The cohort comprised 11,680 patients (median age 64 years); 50.3% were males (5880 of 11,680). The median period of treatment was 9.8 months. Of these patients, 72.7% (n = 8494) were started on rosuvastatin 10 mg/day. A total of 17.5% (n = 2047) of the patients were reported to have stopped treatment with rosuvastatin. Myalgia was the most frequent reason for stopping rosuvastatin and the most frequently reported clinical event. A 2.5-fold increase in the rate of abnormal liver-function tests (LFTs) was observed for patients started on rosuvastatin 40 mg/day compared with those started on 10 mg/day (2.71; 95% CI 1.53, 4.53). No case of rhabdomyolysis was reported in this cohort. CONCLUSION: Rosuvastatin was considered to be a reasonably well tolerated drug. In the majority of patients, rosuvastatin was prescribed in line with recommendations. Abnormality of LFTs was found to be more frequent with the 40 mg/day dosage of rosuvastatin. Results from this study should be taken into account together with those of other clinical and pharmacoepidemiological studies of rosuvastatin.

The safety of quetiapine: results of a post-marketing surveillance study on 1728 patients in England.

The safety of the atypical antipsychotic quetiapine as used in general practice in England was examined by prescription-event monitoring (PEM). Patients were identified from dispensed National Health Service (NHS) prescriptions issued by general practitioners (GPs) for quetiapine between October 1997 and July 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. Green forms with clinically useful information on 1728 patients (median age 39 years (IQR 30-56); 53% female) were received. The most frequently reported event during the first month of treatment was 'drowsiness/sedation' (47; 3% cohort). This was also the most frequently reported specified adverse drug reaction (ADR) to quetiapine (7; 11% of 65 reported ADRs) and the highest reported clinical reason for stopping quetiapine (51; 6% of the 734 reported reasons for stopping). There was a low incidence of extrapyramidal disease (21 during treatment, 1% of cohort) and hyperprolactinaemia (three during treatment, 0.2%) in this study. Three cases of diabetes mellitus in this cohort were reported to be a new diagnosis. Six pregnancies were reported during treatment with quetiapine, five of which were exposed during the first trimester only. There were four Live births with no reported congenital abnormaLities. Fifty-six deaths were reported during this study (3% cohort). The most frequently reported causes of death reLated to the cardiovascular (18) and respiratory (15) systems. The results of this post-marketing surveillance study demonstrated that quetiapine is generally well-tolerated when used in general practice.

Comparison of incidence rates of cerebrovascular accidents and transient ischaemic attacks in observational cohort studies of patients prescribed risperidone, quetiapine or olanzapine in general practice in England including patients with dementia.

Following changes in the safety information on the use of risperidone and olanzapine in elderly patients with dementia, data from prescription-event monitoring (PEM) studies of risperidone, quetiapine and olanzapine were examined. The aim was to compare incidence rates for events reported as cerebrovascular accident (CVA) and transient ischaemic attack (TIA) during the first 180 days of treatment in patients prescribed atypical antipsychotics for dementia or other indications, because of the possible association between dementia and stroke in users of atypical antipsychotics. A retrospective analysis of data from the three observational studies was conducted using Poisson regression modelling and survival analysis. Within the risperidone, quetiapine and olanzapine cohorts, 23 (0.30%), 6 (0.35%) and 10 (0.11%) patients respectively, were reported to have had a CVA/TIA event. Age, sex and indication (dementia or other) were identified as important confounding variables; age being the most important. The crude rate ratios (RRs) for CVA/TIA for risperidone or quetiapine vs. olanzapine indicated an approximate threefold relative difference in rate during the first six months but after adjustment for age, sex and indication, the RRs were non-significant (1.2 (95% CI 0.5,3.0) and 2.1 (95% CI 0.6,7.7), respectively). For risperidone vs. quetiapine, crude and adjusted RRs were not significantly different. Of the three drugs, the time to event was shortest for risperidone and also shortest for risperidone or quetiapine users where the indication was dementia. The age and sex adjusted RR of CVA/TIA in patients prescribed risperidone for dementia vs. other indications was 6.7 (95% CI 2.4,18.9). The adjusted RRs for quetiapine, according to indication, could not be calculated due to missing information on age and sex. There were no cases of CVA/TIA with dementia for olanzapine, thus the RRs and time to event curves according to indication could not be examined. This study revealed no significant difference in the adjusted RR of CVA/TIA events in the first 180 days of treatment in patients prescribed risperidone or quetiapine when compared with olanzapine. However, dementia appears to be an important risk factor. These results should be considered alongside other pharmacoepidemiological studies on this topic.

A post-marketing surveillance study of formoterol (Foradil): its use in general practice in England.

OBJECTIVE: At the time of marketing, experience of long-term use of prescription medicines in general clinical practice is limited. Postmarketing surveillance is particularly important at this time when medicines may be prescribed to large numbers of patients of all ages, for long-term use. Following marketing of formoterol (Foradil) in the UK in 1996 we undertook a postmarketing surveillance study of formoterol use in general practice. DESIGN: A non-interventional observational cohort study was conducted using the technique of prescription-event monitoring. Exposure data were obtained from prescription details; outcome data from questionnaires sent to general practitioners approximately 12 months after the first prescription was dispensed for individual patients. Incidence rates were calculated for reported events, reasons for stopping treatment and outcomes of pregnancy were determined. RESULTS: Data were collected for 5777 patients aged 3 to 96 years, 65% of whom continued treatment for >12 months. Formoterol was prescribed 'off label', to 258 children, (4.5%) of the cohort. The most commonly reported events excluding those related to respiratory disease, were headache, tremor, palpitation, cramp and nausea/vomiting. These events were also among the more common reasons for stopping treatment and reported as suspected adverse drug reactions. 33 patients took formoterol during pregnancy. The cause of death was established for 186 of the 190 deaths (3% of cohort). CONCLUSIONS: Formoterol appears to have been well tolerated by the majority of patients in this study. The most frequently reported adverse events were those known to be associated with beta(2)-agonists, although the frequency of nausea/ vomiting was greater than given in Summary of Product Characteristics.

The pharmacovigilance of pantoprazole: the results of postmarketing surveillance on 11 541 patients in England.

OBJECTIVE: To conduct a postmarketing surveillance study involving patients treated with pantoprazole in general practice in the 6-month period following the launch of this drug in November 1996. Prescription-event monitoring (PEM) provides data on a large cohort of patients in 'real life' settings. The aim was to monitor the safety of pantoprazole as used in general practice. It was the third proton pump inhibitor launched in the UK. METHODS: Patients were identified by data from dispensed prescriptions (FP10s) written by general practitioners (GPs) in England for pantoprazole. Green forms were posted to GPs approximately 6 months following the first prescription identified. GPs were asked to list events that occurred during and after treatment. The incidence density of each event was calculated, ranked and the difference between the incidence of each event in the first and subsequent months of exposure was tested by constructing confidence intervals. RESULTS: Data were collected for 11 541 patients. The major indications for treatment were oesophageal reflux (22.7%) and dyspepsia (16.9%). Of GPs expressing an opinion, 81.9% reported pantoprazole to be effective. GPs reported 107 events as adverse drug reactions. The most frequent reason given for stopping was diarrhoea (106 patients), which corresponded with the adverse event with the highest incidence density. CONCLUSION: This PEM study has defined the reported safety profile of pantoprazole as used in general practice in England. The commonest adverse events found in this study have already been reported in the Summary of Product Characteristics.

Automated signal generation in prescription-event monitoring.

Signal generation is a method of highlighting potential safety issues in a drug that then need to be investigated further. Previously automated signal generation has mainly been applied to spontaneous reporting systems. The Drug Safety Research Unit (DSRU) performs observational postmarketing studies on selected newly marketed medicines in England using a method known as prescription-event monitoring (PEM). The DSRU has investigated automated procedures for the generation of signals using the event data from PEM studies. Proportional reporting ratios (PRRs) and incidence rate ratios (IRRs) were studied as possible tools for signal generation in PEM data. The PEM database contains 78 completed studies of drugs prescribed in primary care from a variety of therapeutic classes. Retrospective studies were carried out to identify the implications of changing the comparator group of drugs, along with analysing the results at different levels in the DSRU's hierarchical dictionary and performing signal generation after 30 and 180 days of observation since starting the drug. Automated signal generation is a useful hypothesis generating method that is likely to prove to be useful both in clinical trials and postmarketing studies. PRRs are simple to apply and do not require a denominator. IRRs take into account the time subjects were exposed to the drug prior to the event of interest, and offers a useful, and more in depth look into the data. However, with both methods it is important to perform signal generation at multiple levels in the dictionary and with careful selection of the comparator group.

The pharmacovigilance of mirtazapine: results of a prescription event monitoring study on 13554 patients in England.

Mirtazpine is the first noradrenaline and serotonin specific antidepressant. We monitored the safety of mirtazapine as reported in primary practice in England. The exposure data were provided by monitoring the dispensed prescriptions issued between September 1997 and February 1999. Questionnaires sent to GPs provided outcome data. Drowsiness/sedation and malaise/lassitude were the most frequent ADRs (116, 71 respectively) and had the highest incidence density (per 1000 patient-months) in the first month of treatment (58.1, 27.8 respectively). Agitation (73), aggression (70), rash (20), hallucinations (13) and abnormal dreams (31 were unlabelled AES while abnormal liver function tests (12), syncope (8), abnormal behaviour (4) and visual disturbance (3) were labelled AES possibly due to mirtazapine use. Serious suspected ADRs reported were facial oedema (5), allergy (3), bone marrow toxicity (2) and myelodysplasia (1).

A modified prescription-event monitoring study to assess the introduction of Flixotide Evohaler into general practice in England: an example of pharmacovigilance planning and risk monitoring.

INTRODUCTION: A modified prescription-event monitoring (PEM) study was conducted to examine the safety of the introduction of the metered dose inhaler (MDI) Flixotide Evohaler (fluticasone with the propellant HFA 134a). METHODS: Patients were identified from the first NHS prescriptions dispensed in England for Flixotide Evohaler. Postal questionnaires were sent to the prescribing doctor, requesting information including: demographic characteristics, severity of indication, concomitant medication, event data 3 months prior to and 3 months after the first prescription, and any reasons for stopping Flixotide. Pregnancies, deaths and selected events were followed up. Incidence density ratios (IDRs) were calculated to compare event rates 3 months before and 3 months after the introduction of Flixotide Evohaler. RESULTS: The cohort comprised 13 413 patients that were prescribed Flixotide Evohaler. The response rate was 64.0%. When the pre- and post-exposure periods were compared fewer patients had events in the post-exposure period, and there was no significant difference in the length of courses of oral steroid use. Eighteen patients experienced an event within 1 hour of using Flixotide Evohaler; these were minor with the exception of one case of angioneurotic facial oedema. Six of these events were assessed as possibly related to Flixotide Evohaler. During the study period there were an additional 13 patients with events assessed as possibly related to Flixotide Evohaler, including two reports of allergic reactions. DISCUSSION: The results suggest that the transition to Flixotide Evohaler was generally well tolerated. The modified methodology has contributed to the risk management of the introduction of this product.

The safety profiles of orlistat and sibutramine: results of prescription-event monitoring studies in England.

INTRODUCTION: Observational cohort studies were conducted using prescription-event monitoring (PEM) to examine the safety profiles of the anti-obesity agents orlistat and sibutramine. Adverse events reported as case reports were also evaluated to determine whether these events were also identified by PEM. RESEARCH METHODS AND PROCEDURES: Patients were identified from dispensed prescriptions written by general practitioners (GPs) in England for orlistat or sibutramine. Patient demographic and clinical event information, including reasons for stopping and adverse drug reactions, were requested on questionnaires posted to GPs at least 6 months after the first prescription for individual patients. Event incidence densities (IDs) (number of first reports of event/1000 patient-months treatment) were calculated for month 1 (ID(1)) and months 2-3 (ID(2-3)). Published case reports were identified by searching Medline and Embase. RESULTS: The cohorts comprised 16,021 and 12,336 patients prescribed orlistat and sibutramine, respectively. Both cohorts had a median age of 45 years, and approximately 80% were female. The most common reason for stopping orlistat within 3 months was diarrhea (332 patients; 2.1% cohort), and for stopping sibutramine it was hypertension (203 patients; 1.6%). Clinical events significantly associated with taking orlistat were mainly gastrointestinal and those for sibutramine included central nervous system effects, nausea/vomiting, palpitation, and sweating. We identified 8 published case reports for orlistat and 10 for sibutramine that had equivalent or similar events assessed as causally related in the PEM studies. CONCLUSIONS: The PEM studies highlighted different adverse event profiles for orlistat and sibutramine that were consistent with their distinct pharmacological mechanisms and other published information.

An observational cohort study investigating the cardiovascular safety of tadalafil when prescribed in primary care in England: mortality due to ischaemic heart disease.

OBJECTIVE: To examine the cardiovascular safety of tadalafil, a phosphodiesterase type-5 inhibitor used for treating erectile dysfunction in patients prescribed this drug by general practitioners (GPs) in England in 2003, focusing on mortality due to ischaemic heart disease (IHD). PATIENTS AND METHODS: Patients in this observational cohort study were identified from dispensed prescriptions for tadalafil issued by GPs from February to November 2003. Demographic and outcome data were requested from patients' GPs using a postal questionnaire. A standardized mortality ratio (SMR) was calculated using indirect standardization for all deaths from IHD or myocardial infarction (MI) in male patients who were prescribed tadalafil, regardless of whether they were taking tadalafil at the time, compared to those in the English male population (2002). RESULTS: Clinical information was obtained for 6266 patients; patient sex could not be confirmed for 37 but in the remaining 6229 the median age was 61 years (interquartile range 53-68). The age was not specified for 2361 (37.7%) of the patients. Excluding patients not taking tadalafil at the time of the event, cardiovascular events included chest pain in 20, angina in 18, MI in 15 (including six fatal) and IHD in 11 (including five fatal). There were also six deaths where the cause was not ascertained; five of these patients were known to be male. Comparison of mortality due to IHD or MI for men with those in the English male population (2002) provided an SMR of 0.91 (95% confidence interval 0.50-1.48). CONCLUSIONS: The results from this study suggest a similar incidence of death due to IHD or MI in men prescribed tadalafil to that in the male English population. However, due to possible under-reporting and the limitations of using an external comparator, these results should be interpreted in context with other studies on the cardiovascular effects and safety of tadalafil.

Examination of the safety and use of apomorphine prescribed in general practice in England as a treatment for erectile dysfunction.

OBJECTIVE: To examine the safety and use of apomorphine as prescribed in general medical practice in England as a treatment for erectile dysfunction (ED). PATIENTS AND METHODS: Apomorphine hydrochloride (marketed as Uprima, Abbott Laboratories Ltd, UK) is licensed in the UK as a sublingual therapy for ED. It is the first treatment for ED with a central mode of action. This postmarketing observational cohort study was conducted using prescription-event monitoring (PEM) methods. Exposure information was obtained from dispensed prescription data for patients first prescribed apomorphine between October 2001 and December 2002. Outcome data were derived from Green-Form questionnaires posted to prescribing physicians > or = 6 months after the date of the first apomorphine prescription for each patient. The study cohort comprised 11 185 patients, 99.3% (11,111) of whom were men, with a median (interquartile range) age of 61 (54-68) years. RESULTS: The most frequently reported prescribing indication was ED and the most frequently reported reason for stopping apomorphine was that it was 'not effective'. In addition, the percentage of patients for whom apomorphine was reported to have been effective was relatively low. Headache was the most commonly reported adverse drug reaction, and the most frequently reported clinical condition occurring in the first month of observation. A small number of events (24) were reported that were not listed in the current Summary of Product Characteristics (SPC) and were considered by the prescribing general practitioner (GP) to be associated with apomorphine use. CONCLUSION: The proportion of patients for whom apomorphine was reported to be effective was low. Also, 'not effective' was the most frequently reported event and a high percentage of patients stopped apomorphine because it was 'not effective'. The most frequently reported clinical adverse events (headache and nausea) were those listed in the SPC. A small number of reports for unlabelled events were thought by prescribers to be related to apomorphine use. The confounding factors of patient age and coexisting disease should be considered when assessing data from this study.

Deep vein thrombosis and pulmonary embolism reported in the Prescription Event Monitoring Study of Yasmin.

AIM: To evaluate cases of deep vein thrombosis (DVT) and pulmonary embolism (PE) reported in a prescription event monitoring study of Yasmin, an oral contraceptive. METHODS: Reports of DVT/PE and events suggestive of DVT/PE were followed up by questionnaire. RESULTS: Thirteen cases (DVT five; PE eight), each with possible risk factor(s), were identified in 15 645 females using Yasmin. Applying complete case analysis, the crude incidence rate was 13.7 cases per 10 000 woman-years (95% confidence interval 7.3, 23.4). CONCLUSIONS: Yasmin is associated with venous thromboembolism. An incidence rate has been calculated, but this may be subject to bias and should be interpreted with caution.

Safety profile of raloxifene as used in general practice in England: results of a prescription-event monitoring study.

Raloxifene, a selective estrogen receptor modulator (SERM) licensed for the prevention of non-traumatic vertebral fractures in postmenopausal women at increased risk of osteoporosis, was launched in the UK in August 1998. The aim of the study was to monitor the safety of raloxifene prescribed in the primary care setting in England using prescription-event monitoring (PEM). Patients were identified by means of prescription data supplied by the Prescription Pricing Authority between September 1998 and November 2000. Demographic and clinical event data were collected from questionnaires posted to primary care physicians (GPs) at least 6 months after the date of the first prescription for each patient. Information on medical events, suspected adverse drug reactions (ADRs), reasons for stopping treatment, pregnancies, and causes of death was requested. Event rates [Incidence Densities (IDs): no. first reports /1000 patient-months of treatment] were calculated. Differences between IDs for events reported in month one (ID(1)) and months 2-6 (ID(2-6)) of treatment were examined. The cohort comprised 13,987 patients [median age 62 years (IQR 55,69); 99.8% female]. The major indication was osteoporosis (40.9%, n=5725). Flushing was the event with the highest ID in month 1 (22.8), reported most frequently by GPs as an ADR to raloxifene (67/461 reports) and as the reason for stopping (700/4592 reports). Events associated with starting treatment included flushing, malaise/lassitude, headache/migraine, nausea/vomiting, sweating, cramp, pain abdomen, dizziness, diarrhea, mastalgia and vaginal hemorrhage. Less common events reported during treatment included deep vein thrombosis (n=13), pulmonary embolism (n=13), thrombophlebitis (n=31) and visual disturbance (n=29). In this study, there were 122 (0.9%) confirmed deaths, of which 32 causes of death were unknown. This study shows that raloxifene is generally well tolerated when used in general practice in England. Potential signals of unrecognised ADRs requiring further evaluation included gastrointestinal adverse symptoms and vaginal hemorrhage. There were also a small number of reports of events associated with venous thromboembolism and visual disorders that require further investigation.