Pain
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There is evidence of greater opioid prescription to individuals in the United States with mental health conditions. Whether these associations generalize beyond the US prescription environment and to familial mental health and socioeconomic status (SES) has not been examined comprehensively. This study estimated associations of diverse preexisting mental health diagnoses, parental mental health history, and SES in childhood with opioid analgesic prescription patterns nationwide in Sweden. ⋯ All mental health conditions were associated with greater LTOT rates (hazard ratios from 1.66 [1.56-1.77] for bipolar disorder to 3.82 [3.51-4.15] for opioid use disorder) and were similarly associated with concurrent benzodiazepine-opioid therapy. Among 1,482,462 adolescents and young adults, initiation and LTOT rates were greater for those with parental mental health history or lower childhood SES. Efforts to understand and ameliorate potential adverse effects of opioid analgesics must account for these patterns.
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Randomized Controlled Trial
A randomised, double blind, placebo-controlled crossover trial of the influence of the HCN channel blocker ivabradine in a healthy volunteer pain model: an enriched population trial.
Preclinical studies suggest that type 2 hyperpolarization-activated cyclic nucleotide gated ion channels (HCN2) are necessary for neuropathic pain. This trial assessed the influence of ivabradine, a nonselective HCN channel blocker, on capsaicin-induced hyperalgesia and pain in healthy human subjects. An enriched population comprising subjects who developed >20 cm of punctate hyperalgesia from topical capsaicin (0.5% cream applied onto 9 cm area) was identified. ⋯ However, ivabradine caused a slowing of heart rate (difference of 10.10 beats per minute [95% confidence interval -6.48 to -13.73; P-value <0.0001]). We conclude that ivabradine lacks analgesic effects in the capsaicin pain model at a dose that caused appreciable slowing of heart rate and, hence, is unlikely to prove a useful analgesic in humans. More selective drugs are required to establish a role of HCN2 for pain in humans.