A change in the trend in dosulepin usage following the introduction of a prescribing indicator but not after two national safety warnings

The cardiovascular safety of tricyclic antidepressants in overdose and in clinical use

Tricyclic antidepressants (TCAs) remain widely prescribed for depression and many other conditions. There may be important differences between individual TCA in regard to their overdose toxicity and their cardiac toxicity in clinical use. We conducted a systematic review to compare the toxicity of individual TCA in overdose and the risk of serious adverse cardiac events occurring with therapeutic doses. We used the fatal toxicity index (FTI) and case fatality ratio as markers of fatality in overdose, and hazard ratios or odds ratios for the risk of cardiovascular adverse events during normal clinical use. In all, 30 reports of mortality in overdose and 14 observational studies assessing the risk of cardiovascular adverse events in clinical use were included. FTI values were of the same order of magnitude (101-102) for all TCAs except lofepramine. Desipramine appears to be somewhat more likely than other TCAs to lead to death in overdose. Amitriptyline, clomipramine, dothiepin/dosulepin, doxepin, trimipramine and imipramine showed broadly similar toxicity and were usually reported to be less toxic than desipramine. Data on nortriptyline were contradictory. Lofepramine had the lowest risk of death in overdose. The rank order of overdose toxicity was broadly consistent between different FTI definitions and between markers used. With respect to the risk of cardiovascular events at clinically relevant exposure, amitriptyline, nortriptyline and lofepramine were associated with a greater risk of in-use cardiotoxicity. All measures of overdose toxicity were subject to external influences and confounding. The continued use of TCAs in depression and other conditions should be minimized when considering their undoubted toxicity in overdose and possible toxicity in normal clinical use.

Antidepressant prescribing patterns and adverse events following introduction of a National Prescribing Indicator to monitor dosulepin usage in Wales

AIMS

Limiting use of the antidepressant dosulepin has been encouraged due to associated risks of toxicity. In April 2011, the All Wales Medicines Strategy Group introduced a National Prescribing Indicator (NPI) to monitor dosulepin usage. The aim of this study was to investigate antidepressant prescribing patterns, and selected adverse events in patients prescribed dosulepin following introduction of the NPI.

METHODS

An e-cohort study was conducted. Adult patients receiving regular dosulepin prescriptions between October 2010 and March 2011 were included. Characteristics of patients who were continued on dosulepin, were switched to an alternative antidepressant or whose dosulepin was discontinued following introduction of the NPI were compared.

RESULTS

In total, 4121 patients were included. Of these, 1947 (47%) continued dosulepin, 1487 (36%) were switched and 692 (17%) discontinued. Of the 692 who discontinued, 92% did not receive a prescription for another antidepressant during the follow-up period. Patients whose dosulepin was discontinued were older and were less commonly coprescribed benzodiazepines. During follow-up, recorded incidence of selected adverse events was low across all groups and no significant difference was observed.

CONCLUSION

Over half of patients had discontinued dosulepin at the end of the period when the NPI was in place. Further interventions may have been required to have a greater impact on prescribing. This study provides some reassurance that dosulepin discontinuation can be a successful strategy, and that the risk of the adverse events investigated was unlikely to have been greater in those who had dosulepin discontinued than in those in whom dosulepin had been continued.

The All Wales Medicines Strategy Group: 18 years' experience of a national medicines optimisation committee

AIMS

To review the medicines optimisation activities of the All Wales Medicines Strategy Group (AWMSG), a committee established in 2002 to advise the Welsh Government on "all matters related to prescribing". Although AWMSG conducts other activities (e.g., health technology appraisal for medicines), we focus here on its role in advising on medicines optimisation.

METHODS

Prescribing indicators have been used in Wales to measure change, together with data on volumes and costs of medicines dispensed. A range of improvement strategies have been categorised under the "four Es", namely educational initiatives, economic incentives, "engineering" and "enforcement".

RESULTS

AWMSG has helped health professionals in NHS Wales to reduce harm and waste, and to reduce inappropriate local or regional duplication and variation. Specific initiatives include the achievement of major cost savings by supporting increased generic prescribing and an "invest to save" approach related to prescribing of hypnotics and tranquillisers, non-steroidal anti-inflammatory drugs (NSAIDs) and proton pump inhibitors. AWMSG also successfully commissioned the introduction of a single national in-patient medication chart for Wales in 2004. Ongoing priorities include a focus on reducing prescribing of certain medicines deemed "low value for prescribing" and on optimising the use of biosimilar medicines.

CONCLUSIONS

Since 2002, AWMSG has acted as a national medicines optimisation committee in Wales. From the outset, pharmacists and clinical pharmacologists have collaborated closely and shared their complementary expertise to make a much greater contribution to the safe, effective and cost-effective use of medicines than either group could have achieved by working separately.

Use of prescribing indicators as a means of identifying variation in the prevalence of valproate prescribing between health communities: a cross-sectional study

Objective

To determine the appropriateness of valproate prescribing indicators in England and Wales as a means of identifying variation in the prevalence of valproate use among women and girls of childbearing potential between health communities.

Methods and analysis

Cross-sectional study using an ecological design using routinely published, publicly available valproate prescribing data for the period January to March 2019 and 2018 mid-year population estimates.

Results

In England and Wales, 87.7 people in every 1000 people prescribed valproate were women or girls aged 14–45 years (range 60.4–133.2). The prevalence of valproate use among all women and girls of childbearing age was 1.49 cases per 1000 women and girls aged 14–45 years (range 0.47–3.13). Considerable variation in prevalence was observed depending on which of two measures was used. The relative risk of exposure between health communities increased from 2.2 to 6.6 depending on the measure used, leading to the identification of different health communities being a priority for action. Wide variation was observed in the prevalence of valproate use among individuals other than women and girls aged 14–45 years (mean prevalence 3.89 cases per 1000 population, range 2.42–7.78). The prevalence of valproate use in all Clinical Commissioning Groups and Local Health Boards was lower in the at-risk population than in the rest of the population (p=0.046) with a strong positive correlation observed between the prevalence of valproate use in these two groups (p<0.001).

Conclusion

Current indicators may lead to a failure to systematically review women and girls of childbearing age prescribed valproate. Urgent consideration should be given to changing the indicators used in England and Wales.

Impact of medicines regulatory risk communications in the UK on prescribing and clinical outcomes: Systematic review, time series analysis and meta-analysis

AIMS

Regulatory risk communications are important to ensure medication safety, but their impact is poorly understood. The aim was to quantify the impact of UK risk communications on medication use and other outcomes.

METHODS

We conducted a systematic review of studies reporting prescribing/health outcome data relevant to UK regulatory risk communication. Data were reanalysed using interrupted time series regression 12 months after each regulatory intervention. Mean changes were pooled using random-effects generic inverse variance examining the following subgroups: drug withdrawals; restrictions/changes in indications; be aware messages without specific recommendations for action; communication via direct healthcare practitioner communications; communication via drug bulletins.

RESULTS

Of 11 466 articles screened, 40 studies examining 25 UK regulatory risk communications were included. Product withdrawals, restriction in indications and be aware communications were associated with relative mean changes of -78% (95% confidence interval [CI] -60 to -96%), -34% (95% confidence interval [CI] -12 to -55%) and -11% (95%CI -8 to -15%) in targeted drug prescribing respectively. Direct healthcare professional communications were associated with relative mean changes of -47% (95%CI -27 to -68%) compared to -13% (95%CI -6 to -20%) for drug bulletins. Of 7 studies examining unique health outcomes related to the safety concern, risk communications were associated with a mean -10% (95%CI -3 to -16%) decrease in intended and a 7% (95%CI 4 to 10%) increase in unintended health outcomes.

DISCUSSION

UK regulatory risk communications were associated with significant changes in targeted prescribing and potential changes in clinical outcomes. Further research is needed to systematically study the impact of regulatory interventions.

Measuring the impact of medicines regulatory interventions - Systematic review and methodological considerations

AIMS

Evaluating the public health impact of regulatory interventions is important but there is currently no common methodological approach to guide this evaluation. This systematic review provides a descriptive overview of the analytical methods for impact research.

METHODS

We searched MEDLINE and EMBASE for articles with an empirical analysis evaluating the impact of European Union or non-European Union regulatory actions to safeguard public health published until March 2017. References from systematic reviews and articles from other known sources were added. Regulatory interventions, data sources, outcomes of interest, methodology and key findings were extracted.

RESULTS

From 1246 screened articles, 229 were eligible for full-text review and 153 articles in English language were included in the descriptive analysis. Over a third of articles studied analgesics and antidepressants. Interventions most frequently evaluated are regulatory safety communications (28.8%), black box warnings (23.5%) and direct healthcare professional communications (10.5%); 55% of studies measured changes in drug utilization patterns, 27% evaluated health outcomes, and 18% targeted knowledge, behaviour or changes in clinical practice. Unintended consequences like switching therapies or spill-over effects were rarely evaluated. Two-thirds used before-after time series and 15.7% before-after cross-sectional study designs. Various analytical approaches were applied including interrupted time series regression (31.4%), simple descriptive analysis (28.8%) and descriptive analysis with significance tests (23.5%).

CONCLUSION

Whilst impact evaluation of pharmacovigilance and product-specific regulatory interventions is increasing, the marked heterogeneity in study conduct and reporting highlights the need for scientific guidance to ensure robust methodologies are applied and systematic dissemination of results occurs.