Clinical toxicology and drug regulation: a United Kingdom perspective

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.

Natural products and their derivatives as cyclooxygenase-2 inhibitors

From ancient times, natural products have been continuously used as therapeutic agents in the treatment of various ailments. Many drugs from the natural origin are available in the market as potent medicines. Over expression of cyclooxygenase-2 (COX-2) enzyme is associated with various physical disorders like various types of inflammations associated with cardiovascular diseases or malignancies. The COX-2 inhibitory activity of many active constituents derived from plants is well established in the literature. These include coumarins, alkaloids, flavonoids, cinnamates, stilbenes and xanthines. In the present review, an attempt has been made to summarize applications of compounds since 2000 obtained from natural sources as COX-2 inhibitors. A brief synthetic methodology to access these natural product derivatives has been highlighted along with the Structure Activity Relationship (SAR).

A study on drug-drug interactions through prescription analysis in a South Indian teaching hospital

OBJECTIVE

The objective of this study was to assess the drug-drug interactions (DDIs) through prescription analysis among the inpatients of a South Indian teaching hospital.

METHODS

The study was a prospective observational prescription analysis conducted for a period of 6 months, from October 2010 to March 2011. The prescriptions having two or more drugs and where a DDI was suspected were selected by the physician in charge of the ward. The drugs in the prescription were then entered into the drug interaction checker software. The DDIs were classified based on the mechanism of interactions, severity of interactions, relation to the number of drugs prescribed, and disease conditions were also determined.

RESULTS

A total of 204 prescriptions were analyzed, of which 186 prescriptions had 856 DDIs. Most of the DDIs were pharmacokinetic drug interactions (42%) followed by unknown mechanisms (34%) and pharmacodynamic mechanisms (24%). The study findings showed that the prescriptions for cardiovascular with respiratory disease conditions had the greatest number of drug interactions on average. A severity assessment showed that majority of the DDIs were moderate (70%) followed by minor (28%). The study results showed that as the number of drugs increases in a prescription, the number of DDIs also increases. The interventions determined showed that dosage adjustment (12%) was to be followed in most of the DDIs.

CONCLUSION

This study assists in understanding the factors associated with DDIs that can help in safe and effective use of drugs in the future.

Dissemination and uptake of a new treatment pathway for paracetamol poisoning in the UK: a survey of healthcare professionals

AIMS

On 3 September 2012, the UK Medicines and Healthcare Products Regulatory Agency (MHRA) notified healthcare professionals of immediate changes to the intravenous acetylcysteine license terms, altering the treatment pathway for paracetamol poisoning. We sought to evaluate awareness of this amongst healthcare professionals.

METHODS

We surveyed doctors, nurses and pharmacists in the 1-12 week period following the implementation date.

RESULTS

Forty-four individuals completed the survey in paper form (response rate 86%) and 220 in electronic form (response rate unknown). The resulting sample of 264 individuals was drawn from 41 institutions, and included 143 doctors, 58 pharmacists and 50 nurses. Of these individuals, 157 (59%) were aware of the changes, and 133 (50%) had adopted them in practice. Awareness differed between healthcare professions (P = 0.001) and specialties (P = 0.002). For respondents aware of the changes, the main sources of information were alerts issued internally (reported by 57%), from the MHRA (25%) and from other professional bodies (24%). The proportion of individuals who reported receiving practical implementation instructions (e.g. a protocol) was higher among respondents who had changed their practice than for those who had not (86 vs. 25%, respectively; P < 0.001).

CONCLUSIONS

Less than two-thirds of healthcare professionals in specialties managing patients with paracetamol poisoning were aware of important changes to its treatment pathway in the 12 weeks after they took effect, and only half had adopted them in practice. Alternative communication strategies should be explored to improve dissemination of similar information from the MHRA and other medicines regulators in the future.

Effects of MHRA drug safety advice on time trends in prescribing volume and indices of clinical toxicity for quinine

AIMS

To ascertain the effects of the Medicines and Healthcare products Regulatory Agency's (MHRA) safety update in June 2010 on the volume of prescribing of quinine and on indices of quinine toxicity.

METHODS

We analysed quarterly primary care total and quinine prescribing data for England and quinine prescribing volume for individual Primary Care Trusts in the North East of England from 2007/8 to 2011/12 obtained from the ePACT.net database. We also analysed quinine toxicity enquiries to the National Poisons Information Service (NPIS) via Toxbase(®) and by telephone between 2004/5 and 2011/12. Joinpoint regression and Pearson's correlation tests were used to ascertain changes in trends in prescribing and indices of toxicity and associations between prescribing and indices of toxicity, respectively.

RESULTS

Total prescribing continued to increase, but annual growth in quinine prescribing in England declined from 6.0 to -0.6% following the MHRA update [difference -0.04 (95% confidence interval -0.07 to -0.01) quinine prescriptions per 100 patients per quarter, P = 0.0111]. Much larger reductions were observed in Primary Care Trusts that introduced comprehensive prescribing reviews. The previously increasing trend in Toxbase(®) quinine searches was reversed [difference -19.76 (95% confidence interval -39.28 to -9.20) user sessions per quarter, P = 0.0575]. Telephone enquiries to NPIS for quinine have declined, with stabilization of the proportion of moderate to severe cases of quinine poisoning since the update.

CONCLUSIONS

The MHRA advice was followed by limited reductions in the growth in quinine prescribing and in indicators of quinine overdose and toxicity. Quinine prescribing, however, remains common, and further efforts are needed to reduce availability and use.

Impact of amending the acetylcysteine marketing authorisation on treatment of paracetamol overdose

In September 2012, the Medicines and Healthcare products Regulatory Agency (MHRA) substantially amended the Marketing Authorisation for acetylcysteine following an extensive review. The present study examined the impact of this license change on patterns of acetylcysteine use in patients presenting to hospital after paracetamol (acetaminophen) overdose. Between September 2011 and April 2013, 785 consecutive patients presented to York Hospital due to paracetamol overdose, and a before-after analysis was used to compare outcomes. There were 483 patients before and 302 patients after the license amendment, and age, gender, acute or staggered overdose pattern, and dose were similar in both groups. In the patients with paracetamol concentrations between the "100-line" and "200-line," a significantly higher proportion received acetylcysteine treatment (51% before versus 98% after, P = 0.0029), as expected. A modest increase was also observed in relation to late or staggered overdose or cases where the time of ingestion was uncertain (53% versus 74%, P = 0.0430). The median duration of hospital stay increased across the entire study population, from 15 to 24 hours (P = 0.0159) due to the increased proportion of patients requiring acetylcysteine treatment. The findings indicate that the MHRA amendment is a financially costly intervention, and further studies are needed to examine clinical outcomes so that its cost effectiveness might be addressed.

The role of Periodic Safety Update Reports in the safety management of biopharmaceuticals

PURPOSE

To describe and assess the outcomes of Periodic Safety Update Report (PSUR) evaluations of biopharmaceuticals.

METHODS

A cross-sectional analysis was performed of follow-up requirements of PSURs submitted for centrally approved biopharmaceuticals in the European Union between 1 July 2008 and 30 June 2010. A follow-up analysis on a subset of products that submitted multiple PSURs within the study period was also performed.

RESULTS

The cross-sectional analysis included 70 PSURs. Potential safety concerns occurred in 57 (83 %) of all PSURs, and 26 (37 %) concluded a need to change the Summary of Product Characteristics (SPC). In comparison to newer products, products authorized for more than 10 years contained significantly fewer potential safety concerns (60 vs. 92 %; p < 0.01) and required fewer SPC changes (15 vs. 46 %; p = 0.03). For 45 products, multiple PSURs were submitted that could be included in a follow-up analysis. For this subset of products, of the 106 newly identified safety potential safety issues, 7 (7%) resulted in requirements for label changes in the following PSUR.

CONCLUSIONS

PSURs facilitate communication between regulators and marketing authorization holders. Potential safety concerns occur for the majority of biopharmaceuticals and throughout their lifecycle, but for established products PSUR evaluations rarely lead to regulatory actions.

Comparative drug dose and drug combinations in patients that present to hospital due to self-poisoning

Self-poisoning is a common reason for acute presentation to hospital. Commonly involved drugs have been reported, but few data exist concerning the different combinations of agents or comparative doses ingested. The present study sought to better characterise the typical patterns of drug overdose that may present via the emergency department. Consecutive adults ≥16 years of age that presented to York Hospital owing to self-poisoning were studied for 2010-2011 inclusive. The primary outcome measure was reported dose, expressed as a multiple of the defined daily dose (DDD) to allow comparison between different agents. There were 1024 patients, including 622 women (60.7%), and median age was 32 years (range, 16 to 92 years). Overdose in men was associated with a higher overall quantity of drugs: arithmetic mean of 20 DDD multiples (95% CI, 15-26) versus 13 (11-15), p = 0.001. Overdose involved a single agent only in 538 patients (52.5%). The mean paracetamol dose was 4.0 (95% CI, 3.7-4.3) DDD multiples; the doses of antidepressants (19.4, 17.0-21.7, p < 0.0001) and benzodiazepines (18.0, 12.8-23.2, p < 0.0001) were comparatively higher. The types of agents involved in self-poisoning and common combinations of agents are characterised. Psychotropic medications were ingested in comparatively larger quantities than analgesic agents and had worse clinical outcome. Further work is required to understand the factors that determine the quantity of drug ingested in patients at risk of drug overdose so as to minimise the risk of significant toxicity.