Abstract
Aims: Daily broad-spectrum micronutrients are being used by the general public and formulations are receiving research interest in mental health settings. Despite concerns about combining medicines and broad-spectrum micronutrients in mental health care, there have not been any formal evaluations of potential interactions. Our objective was to evaluate a broad-spectrum micronutrient formula as a potential precipitant of pharmacokinetic drug-drug interactions through inhibition or induction of cytochrome P450 (CYP) enzymes.
Methods: This was a single-centre pharmacokinetic study. Twelve healthy participants received broad-spectrum micronutrients for 14 days (Days 1-14). Participants were administered a 'cocktail' of selective CYP probes midazolam 2 mg (CYP3A), dextromethorphan 30 mg (CYP2D6), losartan 25 mg (CYP2C9), omeprazole 20 mg (CYP2CI9) and caffeine 100 mg (CYP1A2) on Day 0 and Day 14, before taking and while taking broad-spectrum micronutrients. Plasma drug concentrations were measured at baseline and for 8 h following cocktail administration. AUC, Cmax and Tmax were compared before and after broad spectrum micronutrient administration using paired t-tests.
Results: Pre- and post-micronutrient geometric means (SD) for AUC0-8h (μg*h/L) were: midazolam 25 (13) and 26 (14), P = 0.60; dextromethorphan 25 (99) and 19 (110), P = 0.46; losartan 219 (105) and 205 (76), P = 0.20; omeprazole 474 (394) and 402 (342), P = 016; and caffeine 13 800 (5400) and 12 800 (3500), P = 0.79. There were no statistically significant changes in geometric means of probe Cmax, or Tmax for any of the study drugs.
Conclusions: Broad-spectrum micronutrients are unlikely to be a major precipitant of pharmacokinetic drug-drug interactions.