Non-response in a pharmacy and patient-based intensive monitoring system: a quantitative study on non-response bias and reasons for non-response.

OBJECTIVE: Worldwide pharmacists play an increasingly important role in pharmacovigilance. Lareb Intensive Monitoring (LIM) in the Netherlands is a new form of active pharmacovigilance where pharmacists play a key role. Patients using drugs which are monitored are identified in the pharmacy and invited to participate in the active monitoring. Not all invited patients participate. This study aimed to investigate non-response bias in LIM, as well as reasons for non-response in order to identify barriers to participation. METHODS: The study population consisted of patients who received a first dispensation of an antidiabetic drug monitored with LIM between 1 July 2010 and 28 February 2011. Possible non-response bias was investigated by comparing age, gender and the number of drugs used as co-medication. Reasons for non-response were investigated using a postal questionnaire. KEY FINDINGS: Respondents were on average 4.5 years younger than non-respondents and used less co-medication. There were no differences regarding gender. The main reason for non-response was that information in the pharmacy was lacking. CONCLUSION: Differences between respondents and non-respondents should be taken into account when analysing and generalising data collected through LIM, as this might contribute to non-response bias. The relatively high response to the postal questionnaire, together with the answers about reasons for non-response, show that patients are willing to participate in a web-based intensive monitoring system, when they are informed and invited in the pharmacy.

Neuropsychiatric adverse events of varenicline: a systematic review of published reports.

INTRODUCTION: Over the past years, the impact of varenicline in patients with mental illness has been debated as serious neuropsychiatric adverse events (AEs) have been reported with varenicline use. AIM: To identify and summarize published case reports of neuropsychiatric AEs ascribed to varenicline and to determine potential risk factors for these AEs. METHODS: A literature search of MEDLINE, the Cochrane Library, EMBASE, and PsychInfo database was conducted for case reports concerning the neuropsychiatric AEs of varenicline published in English from 2006 (approval year by the US Food and Drug Administration and the Dutch Medicines Evaluation Board) to January 1, 2012. RESULTS: We identified 25 published cases. In most reports, patients had been admitted to psychiatric hospitals with serious neuropsychiatric AEs due to varenicline. The average patient age was 46.4 years, and 56% were men; 68% of patients had a psychiatric history. The onset of symptoms started 2 days to 3 months after the initiation of varenicline. One report described completed suicide in a man with no psychiatric history. In most cases (84%), the neuropsychiatric symptoms resolved after the discontinuation of varenicline. Analysis of all reports using the Naranjo causality scale, a method for estimating the probability of adverse drug reactions, indicated probable causality in 76% of the cases and definite causality in 12% of cases. CONCLUSION: Varenicline is associated with an increased risk of serious neuropsychiatric AEs, especially in patients with a psychiatric illness. It is strongly recommended that varenicline be administered only to mentally stable patients and under close monitoring.