Andrew Boshier

Cardiovascular events in users of sildenafil: results from first phase of prescription event monitoring in England

Sildenafil is used to treat erectile dysfunction, and prescription on the NHS is restricted. We are conducting a study of prescription event monitoring for sildenafil in England, the first phase of which investigates possible short term effects in a cohort of about 5000 users. In view of the interest in myocardial infarction as a possible short term side effect1 we report on an analysis of selected cardiovascular events reported in the first phase. Prescription event monitoring has been described elsewhere.2 Patients were identified from NHS prescriptions in England. Simple questionnaires were posted to the prescribing general practitioners about five months after the first prescription. These forms requested reporting of events after the drug had been prescribed. An “event” was any new diagnosis, any reason for referral to a consultant or admission to hospital, unexpected deterioration (or improvement) in a …

Serious skin reactions and selective COX-2 inhibitors: a case series from prescription-event monitoring in England.

AbstractBackground: The erythema multiforme (EM) spectrum of bullous eruptions (toxic epidermal necrolysis [TEN] and Stevens-Johnson syndrome [SJS]) are rare and serious skin reactions that have been reported for cyclo-oxygenase (COX)-2 selective inhibitors. Our objectives were to identify and describe cases of serious skin reactions reported during postmarketing studies of COX-2 selective inhibitors. Methods: A retrospective review of information from reports of serious skin reactions reported during prescription-event monitoring (PEM) studies of rofecoxib, celecoxib, etoricoxib and valdecoxib conducted in England since 1999. Exposure data were derived from dispensed prescriptions written by primary care physicians for each study drug. Outcome data were derived from questionnaires posted to prescribers at least 9 months after the date of the first prescription for each patient (valdecoxib data collection ongoing at the time of this study). Reports of EM, exfoliative dermatitis, SJS, TEN and symptoms associated with EM (EM syndrome) were identified from the PEM database. Additional data on diagnosis, relevant risk factors and management were requested for each case from the prescriber. A causality assessment was undertaken by a Drug Safety Research Unit research fellow and referred for expert review to a consultant dermatologist. Results: Nine cases of serious skin reactions and two cases of symptoms associated with EM (EM syndrome) were identified. No reports of TEN were recorded. Six skin reaction questionnaires were returned. Of the nine cases of serious skin reactions, four cases (all SJS; one for each COX-2 selective inhibitor studied) were assessed as possibly related to use of the study drug (for combined cohorts: incidence risk 0.008%, 4 of 52 644 patients; rate 0.019 per 1000 patient-months of treatment). These four cases (two male, two female; age range 54–64 years) occurred within 2 weeks of starting treatment; the patient prescribed rofecoxib had reported risk factors (history of allergy, adverse reaction [asthma] to ibuprofen). The two cases from the EM syndrome search (one female, 35 years; one male, 80 years) occurred within 2 weeks of starting treatment; both were assessed as possibly related to use of celecoxib but considered suggestive of angio-oedema/urticaria and hypersensitivity reactions. Conclusions: This case series provides useful and complementary information to other published studies about serious skin reactions reported during treatment with COX-2 selective inhibitors. The crude incidence of cases of SJS possibly related to the use of a COX-2 selective inhibitor in this case series is very low (0.008% for all four cohorts combined). Prescribers and patients should be aware of the severe and life-threatening risk of EM potentially associated with NSAIDs, including COX-2 selective inhibitors.

Evaluation of the safety of sildenafil for male erectile dysfunction: experience gained in general practice use in England in 1999.

To examine the safety of sildenafil, the first of the phosphodiesterase type 5 inhibitors licensed for the treatment of male erectile dysfunction (ED), as used in general medical practice in England, quantifying the incidence of a range of events in patients treated with sildenafil, and identifying any previously unrecognized adverse drug reactions.

Comparison of the risk of drowsiness and sedation between Levocetirizine and Desloratadine: a prescription-event monitoring study in England

AbstractBackground and objectives: Desloratadine and levocetirizine are histamine H1 receptor antagonists (antihistamines) that were launched in the UK in 2001. Our objective was to compare the frequency with which drowsiness and sedation were reported for desloratadine and levocetirizine within the first 30 days of observation, as monitored using the observational cohort technique of prescription-event monitoring (PEM). Methods: Exposure data were derived from dispensed prescriptions written by primary care physicians and outcome data were derived from questionnaires that were posted to prescribers at least 6 months after the date of the first prescription for each patient. The odds ratio (OR) was calculated using unconditional logistic regression modelling. The effect of age, sex, reported prescribing indication (allergic rhinitis with asthma/wheezing, allergic rhinitis without asthma/wheezing, ‘other’), pattern of use and reported previous antihistamine use on the OR was examined. A time-to-event analysis was performed. Results: The cohorts comprised >24 000 patients in total. Cohort demographics were similar (both cohorts: median age 37 years; 60% women); the most frequently reported prescribing indication for both drugs was allergic rhinitis without asthma/wheezing (54%). The incidence of first reports of drowsiness/sedation for levocetirizine or desloratadine was low (46 [0.37%] and 9 [0.08%], respectively) and statistically different (p < 0.0001). These events tended to occur earlier for desloratadine than levocetirizine (50% at 7 or 14 days of observation, respectively; p = 0.6487), but the cumulative time to event differed, with more events observed for levocetirizine than expected (p < 0.0001; 46 vs 28.09). The final estimates of risk were the sex-adjusted ORs for each prescribing indication category: allergic rhinitis with asthma/wheezing (3.51; 95% CI 0.71, 17.43; n = 3357), allergic rhinitis without asthma/wheezing (6.75; 95% CI 2.37, 19.22; n = 12 627) and ‘other’ (3.11; 95% CI 0.86, 11.31; n = 6725). Discussion: Although the reporting rates of drowsiness and sedation are low for both drugs, patients prescribed levocetirizine are more likely to experience drowsiness and sedation in the first month of observation (after starting treatment) than patients prescribed desloratadine. For patients with allergic rhinitis without asthma/wheezing, the sex-adjusted odds of drowsiness/sedation were over six times greater in patients using levocetirizine than desloratadine in the first month of observation, with the OR being statistically significant. For the other two indication categories, allergic rhinitis with asthma/wheezing and ‘other’, the OR was not statistically significant. Conclusions: Although the risk of drowsiness/sedation is low, conditions such as allergic rhinitis are common, which makes any impact on patient cognitive function important. Doctors should be aware of this when prescribing these products to patients where daytime sedation is undesirable. However, essential components of the comparative benefit-risk evaluation of these two products include assessment of efficacy and patient preference (neither of which forms part of this study).

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

To examine the safety and use of apomorphine as prescribed in general medical practice in England as a treatment for erectile dysfunction (ED).

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

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).