FIGURE 1.

Kratom-related publications (A), opioid prescribing rates (B) and number of opioid overdose deaths (C) for years 2000–2019. The number of Kratom-related publications (Figure 1A) was obtained from a search of the United States National Library of Medicine’s PubMed database, using the search term “kratom” on april 26, 2021. The solid black line shows the total number of publications for each year, whereas the broken line shows the number of publications in which at least one author was based in the United States. The data for opioid prescribing rates for the years 2000–2006 were obtained from (Kenan et al., 2012); data for the years 2006–2019 were obtained from the CDC database at https://www.cdc.gov/drugoverdose/maps/rxrate-maps.html. Each point represents the number of prescriptions per 100 people for each year. Please note that only 10–20% of people received any prescriptions which indicates that people received multiple prescriptions within the same year. Data for the number of opioid-related overdose deaths by drug type were obtained from both the CDC and NIDA data bases at https://www.cdc.gov/nchs/data/databriefs/db394-tables-508.pdf#page=3 and http://www.drugabuse.gov/drug-topics/trends-statistics/overdose-death-rates. All of these databases are in the public domain. The data that were extracted and used for these analyses are included as a supplemental table.