BACKGROUND: Krokodil is an informal term for a cheap injectable illicit drug 
domestically prepared from codeine-containing medication (CCM). The method of 
krokodil preparation may produce desomorphine as well as toxic reactants that 
cause extensive tissue necrosis. The first confirmed report of krokodil use in 
Russia took place in 2004. In 2012, reports of krokodil-related injection 
injuries began to appear beyond Russia in Western Europe and the United States.
OBJECTIVE: This exploratory study had two main objectives: (1) to determine if 
Internet search patterns could detect regularities in behavioral responses to 
Russian CCM policy at the population level, and (2) to determine if 
complementary data sources could explain the regularities we observed.
METHODS: First, we obtained krokodil-related search pattern data for each Russia 
subregion (oblast) between 2011 and 2012. Second, we analyzed several 
complementary data sources included krokodil-related court cases, and related 
search terms on both Google and Yandex to evaluate the characteristics of terms 
accompanying krokodil-related search queries.
RESULTS: In the 6 months preceding CCM sales restrictions, 21 of Russia's 83 
oblasts had search rates higher than the national average (mean) of 16.67 
searches per 100,000 population for terms associated with krokodil. In the 6 
months following restrictions, mean national searches dropped to 9.65 per 
100,000. Further, the number of oblasts recording a higher than average search 
rate dropped from 30 to 16. Second, we found krokodil-related court appearances 
were moderately positively correlated (Spearman correlation=.506, P≤.001) with 
behaviors consistent with an interest in the production and use of krokodil 
across Russia. Finally, Google Trends and Google and Yandex related terms 
suggested consistent public interest in the production and use of krokodil as 
well as for CCM as analgesic medication during the date range covered by this 
study.
CONCLUSIONS: Illicit drug use data are generally regarded as difficult to obtain 
through traditional survey methods. Our analysis suggests it is plausible that 
Yandex search behavior served as a proxy for patterns of krokodil production and 
use during the date range we investigated. More generally, this study 
demonstrates the application of novel methods recently used by policy makers to 
both monitor illicit drug use and influence drug policy decision making.