AimsLittle is known about the frequency with which suspected adverse drug reactions are seen by general practitioners after the prescription of newly marketed drugs. We investigated age and sex specific incidence rates of suspected adverse drug reactions recorded by general practitioners in England after the prescription of selected newly marketed drugs. Methods Information was collected from 48 national cohort studies of newly marketed drugs studied by prescription-event monitoring. Questionnaires were sent to prescribers asking for details of events and suspected adverse drug reactions recorded in the patients' notes occurring after the drugs were prescribed. Results During the 48 cohort studies, a total of 513 608 patients were investigated, of which 221 781 (43.2%) were males and 285 862 (55.7%) were females. The overall incidence of suspected adverse drug reactions in males was 12.9 per 10 000 patientmonths of exposure (95% confidence limits 12.3 to 13.5), and in females was 20.6 per 10 000 patient-months of exposure (95% confidence limits 19.9 to 21.3). The overall age-standardised relative risk of an adverse drug reaction in females compared with males was 1.6 (1.5-1.7). This sex difference was significant in all age groups above 19 years of age, and was relatively consistent across all age groups (x 2 test for heterogeneity= 9.2, P=0.3). The highest rate of recording in males was in the 50-59 year age group, and in females was in the 30-39 year age group. Conclusions In general practice in England, suspected adverse drug reactions to newly marketed drugs are recorded more often in adults aged between 30 and 59 years of age and are 60% more common in women than in men. The sex difference occurs in all age groups over 19 years of age.

Summary:Purpose: To examine the safety of lamotrigine (LTG) used in general practice to treat epilepsy.Methods: Information was collected on 11,316 patients who were included in a noninterventional observational cohort study conducted by means of Prescription-Event Monitoring (PEM). A follow-up study provided information on the first 3,994 patients who had taken LTG for 3 6 months. Incidence density (ID) measurements were used to rank the frequency of the reported events.Results: Rash was the most frequently reported nonepileptiform event (ID, 19.7/1,000 patient-months) in the first month of treatment and resulted in LTG being stopped in 2% of the 11,316 patients. Rash was reported more frequently among children aged 2-12 years (ID, 29.4/1,000 patient-months) than adults. Other events associated with the use of LTG included headache, drowsiness, nausea, vomiting, malaise, and lassitude.Rare serious events possibly associated with LTG included 12 cases reported as Stevens-Johnson syndrome, four cases of neutropenia, three cases of thrombocytopenia, and two cases of disseminated intravascular coagulation. There were also individual cases of leucopenia, a meningitic reaction, acute renal failure, hepatotoxicity, and a "lupus-like'' reaction possibly associated with the drug. No foetal abnormalities were specifically associated with the use of the drug in pregnancy. No death was attributed to LTG.Conclusions: Patients had severe epilepsy, inadequately controlled by other antiepileptic agents. The results of these two studies suggest that LTG is acceptably safe when used for the treatment of refractory epilepsy. Key Words: LamotrigineEpilepsy-Drug safety-Prescription-Event MonitoringRash.Lamotrigine (LTG) is a relatively new antiepileptic agent (AED) initially licensed as add-on therapy for seizures inadequately controlled by other drugs. LTG is therefore usually prescribed for patients with chronic, severe epilepsy, already being treated by other agents. The safety of LTG in these patients is of importance to both neurologists and general practitioners (GPs).A study was conducted by Prescription-Event Monitoring (PEM) to establish the safety of LTG. PEM identified events over an observation period of -6 months. As LTG is routinely intended for long-term use, a follow-up study was carried out to identify long-latency events in those patients who took the drug for >6 months.We report the results of the PEM study and the follow-up study.

Aims To estimate the rates of common adverse events in patients treated with the proton pump inhibitors omeprazole, lansoprazole and pantoprazole in general practice in England. Methods In prescription‐event monitoring cohort studies, data on dispensed prescriptions prescribed by general practitioners in England soon after each drug was launched were linked to subsequent clinical events recorded by the prescriber. 16 205 patients prescribed omeprazole between June 1989 and June 1990, 17 329 patients prescribed lansoprazole between May and November 1994, and 11 541 patients prescribed pantoprazole between December 1996 and June 1997 were studied. Results The commonest adverse events in the omeprazole, lansoprazole and pantoprazole cohorts were diarrhoea (incidence: 0.18, 0.39 and 0.23 per 1000 days of exposure, respectively); nausea/vomiting (incidence: 0.16, 0.22 and 0.18 per 1000 days of exposure, respectively); abdominal pain (incidence: 0.17, 0.21 and 0.17 per 1000 days of exposure, respectively); and headache (incidence rates: 0.10, 0.17 and 0.15 per 1000 days of exposure, respectively). The remaining adverse events occurred at rates of less than 0.11 per 1000 days of exposure. There were little absolute differences in the rates of most events between the three proton pump inhibitors. However, diarrhoea was more commonly associated with lansoprazole compared with omeprazole (rate difference: 0.21 per 1000 days of exposure; 95% CI 0.17, 0.25; rate ratio: 2.11; 1.78, 2.51), and there was a clear age‐response relationship. Conclusions Adverse events occurred relatively infrequently in all three cohorts. There were only small absolute differences in event rates between the three drugs, although these data suggest the hypothesis that lansoprazole is associated with more frequent occurrence of diarrhoea, particularly in the elderly.

Olanzapine is an 'atypical' antipsychotic indicated for the treatment of schizophrenia. We analysed adverse events (AEs) reported in primary practice in England. Dispensed prescriptions issued between December 1996 and May 1998 provided exposure data. Questionnaires sent to general practitioners provided outcomes. Frequently reported AEs were: drowsiness/sedation (n = 19), extrapyramidal disorder (n = 13) and unspecified side-effects (n = 33). Events with highest incidence density in first month and reason for stopping were: drowsiness/sedation [n = 153, incidence density (ID)1 18.9], weight gain (n = 117, ID1 8.9) and malaise/lassitude (n = 65, ID1 5.2). Extrapyramidal disorders were more common in elderly population (> 70 years, ID1 3.6, risk 26.0 per 1,000 patients) compared to < 70 years (ID1 1.1, risk 8.4 per 1,000 patients). Serious suspected adverse reactions were neuroleptic malignant syndrome (n = 1) and angioneurotic ooedema (n = 2). There were eight reports of diabetes mellitus assessed as possibly due to olanzapine. Diabetes mellitus was an unlabelled AE and possible signal generated by prescription-event monitoring.

Background-The long term safety of agonists, particularly in patients with heart disease, has not been fully established. Rates and relative risks of non-fatal cardiac failure and ischaemic heart disease were calculated, comparing bambuterol and salmeterol with the reference drug nedocromil. Results-The age and sex adjusted relative risk of non-fatal cardiac failure associated with bambuterol was 3.41 (95% confidence limits (CL) 1.99 to 5.86) when compared with nedocromil. When salmeterol was compared with nedocromil the adjusted relative risk of non-fatal cardiac failure was 1.10 (95% CL 0.63 to 1.91). The adjusted relative risk of non-fatal ischaemic heart disease was 1.23 (95% CL 0.73 to 2.08) and 1.07 (95% CL 0.69 to 1.66) for bambuterol and salmeterol, compared with nedocromil, respectively. However, in the first month of exposure the adjusted relative risk of non-fatal ischaemic heart disease was 3.95 (95% CL 1.38 to 11.31) when bambuterol was compared with nedocromil. Conclusions-Caution should be exercised when prescribing long acting oral agonists to patients at risk of cardiac failure. More definitive evidence would come from prospective randomised trials. (Thorax 1998;53:558-562) Methods-This