Study of natural health product–drug adverse reactions (S.O.N.A.R.) in patients seeking mental health services

Abstract

Background: Natural health products (N.H.P.s) are frequently used by mental health patients, who are also more likely to be given prescription medications. Few patients report use of N.H.P.s to their health care providers, increasing the challenges of safe N.H.P. use.Objective: To determine: (1) the proportion of patients seeking mental health services taking prescription drugs only, N.H.P.s only, prescription drug–N.H.P.s concurrently and neither, (2) which prescription drugs and N.H.P.s are most commonly used by these patients, either alone or in combination, (3) what proportion of patients in each of the above groups report an adverse event (A.E.) using active surveillance, and (4) what type of A.E.s are reported in these patient groups.Method: Employing active surveillance, participating clinicians from six mental health clinics in Edmonton, Alberta asked individuals seeking mental health services about (i) prescription drug use, ii) N.H.P. use, and iii) experiences of A.E.s.Results: Of 1466 patients with complete screening data available, 672 (45.8%) patients took prescription drugs only, 79 (5.4%) took N.H.P.s only, 279 (19.0%) took N.H.P.s and drugs concurrently and 436 (29.7%) took neither. In total, 147 patients reported an A.E., representing 10.7%, 2.5%, 25.5% and 0.5% of each population, respectively. Compared with prescription drug use, patients reporting concurrent N.H.P.–drug use were 2.8 times more likely to experience an A.E. (95% C.I.: 2.0–4.1; p < 0.001). A key limitation of the study is the lack of causality assessment of A.E.s reported; additionally, the patient population reflects a population that phones a provincial mental health phone line with or without referral from a mental health professional.Conclusion: Nearly one-fifth of patients seeking mental health services take N.H.P.s and prescription drugs concurrently; these patients are also at a greater risk of experiencing an A.E. Active surveillance provides a valuable means of detecting such A.E.s and can be incorporated into the medical histories obtained by clinicians.