Study of Natural Health Product Adverse Reactions (SONAR): Active Surveillance of Adverse Events Following Concurrent Natural Health Product and Prescription Drug Use in Community Pharmacies

Abstract

BackgroundMany consumers use natural health products (NHPs) concurrently with prescription medications. As NHP-related harms are under-reported through passive surveillance, the safety of concurrent NHP-drug use remains unknown. To conduct active surveillance in participating community pharmacies to identify adverse events related to concurrent NHP-prescription drug use.Methodology/Principal FindingsParticipating pharmacists asked individuals collecting prescription medications about (i) concurrent NHP/drug use in the previous three months and (ii) experiences of adverse events. If an adverse event was identified and if the patient provided written consent, a research pharmacist conducted a guided telephone interview to gather additional information after obtaining additional verbal consent and documenting so within the interview form. Over a total of 112 pharmacy weeks, 2615 patients were screened, of which 1037 (39.7%; 95% CI: 37.8% to 41.5%) reported concurrent NHP and prescription medication use. A total of 77 patients reported a possible AE (2.94%; 95% CI: 2.4% to 3.7%), which represents 7.4% of those using NHPs and prescription medications concurrently (95%CI: 6.0% to 9.2%). Of 15 patients available for an interview, 4 (26.7%: 95% CI: 4.3% to 49.0%) reported an AE that was determined to be “probably” due to NHP use.Conclusions/SignificanceActive surveillance markedly improves identification and reporting of adverse events associated with concurrent NHP-drug use. Although not without challenges, active surveillance is feasible and can generate adverse event data of sufficient quality to allow for meaningful adjudication to assess potential harms.

Pharmacy study of natural health product adverse reactions (SONAR): a cross-sectional study using active surveillance in community pharmacies to detect adverse events associated with natural health products and assess causality

“…By improving the rates of AE identification and reporting, possible harms can be detected sooner, and even prevented. Our study screening questions are brief, taking approximately 15 seconds per patient to administer 19. Health professional prompting will increase the discussion around NHPs with their patients as well as improve awareness of the therapies their patients are engaged in so as to improve safety and health outcomes.…”

“…Typically, NHPs are considered by users to be safe since they are ‘natural’13; however, studies demonstrate some serious toxicities and many possible adverse reactions (ARs) with the use of these products 3 11–15. Further, NHP use is higher among patients with chronic medical conditions,16 17 where prescription drug use is likely: 58% of cardiovascular patients taking narrow therapeutic index drugs used NHPs and prescription drugs concurrently,18 compared with 39.7% of community pharmacy patients screened in Ontario (ON) 19. In patients over 50 years old, 87.4% of those taking NHPs did so in combination with drugs 20.…”

Melatonin Interaction Resulting in Severe Sedation

“…Detailed methods have been presented previously (9,10) In brief, adverse events were identified in a community pharmacy where participating pharmacists and pharmacy staff were systematically asking patients collecting prescriptions for conventional medicines whether they had recently been taking NHPs such as herbal medicines, vitamins, minerals or other supplements together with prescription medications and whether they had experienced an unwanted or unexpected effect. Where adverse events were identified, the study team then obtained informed written consent from the patient prior to an in-depth guided telephone interview.…”

“…A formidable challenge for pharmacovigilance of NHPs is the under-reporting of suspected adverse drug reactions associated with these products (7,8). The Pharmacy Study Of Natural health product Adverse Reactions (SONAR) is a multi-centre study assessing the feasibility of a community pharmacy-based active surveillance system to identify adverse reactions related to NHPs (9,10). The study identified a patient who presented with severe sedation after intake of melatonin with two antidepressants (citalopram and nortriptyline) and one opioid analgesic (oxycodone).…”

The use of natural health products by paediatric patients in respite care

“…Despite the frequent use and popularity of alternative remedies, the potential benefits and risks of their use are not always clear. This uncertainty is due to several factors: use of alternative medicine is unconventional; preparations rarely meet the required standards of consistency in composition and biological activity; there is a lack of reporting of adverse events and drug interactions (6) due to a lack of professional surveillance; and specific data on organ toxicity are not readily available (7). Furthermore, many complementary health products and practices are not tested for safety or effectiveness in children, and many patients assume NHPs are safe because they are 'natural' and are unaware of any risks associated with their use.…”