Credit: CFSRE
Scientists from the Center for Forensic Science Research & Education (CFSRE) identified the adulterant quinine in up to 57% of seized drug cases in the U.S., however, positivity varied greatly by state and rapidly declined in early 2022.
For example, no quinine was detected in seized drugs in California and only two in Texas. Meanwhile, in Vermont, quinine was present in 140 of 244 samples (57%), while 49 of 91 samples (54%) tested positive in Washington, D.C. The rest of the states—Florida, Pennsylvania, New Hampshire, Ohio, Illinois and Kentucky—ranged from 7% to 21% positivity.
Quinine has been reported as an adulterant in the illicit drug supply, including heroin, fentanyl, methamphetamine and cocaine, for many decades. It is generally added to increase total drug volume for distribution and to dilute the drug being cut.
In postmortem toxicology samples, however, CFSRE scientists did record a decreased in quinine presence over the past four years.
In Q1 of 2018, 22% of postmortem samples contained quinine. Positivity peaked in Q3 of 2018 with 38% of the samples testing positive for the adulterant. In Q1 of 2022, only 14% of samples were found to contain quinine—but the forensic scientists found an increase in other adulterants such as xylazine and levamisole.
According to CFSRE, acute quinine poisoning can lead to cinchonism, which includes symptoms such as hearing loss, tinnitus, dizziness, flushing, blurred vision and headache. Consumption of larger doses can result in nausea, vomiting and visual disturbances. In cases of severe overdose, quinine can result in cardia and platelet disorders, including arrythmia, chest pain and thrombocytopenia. If an overdose is not treated in a timely manner, patients may experience long-term vision loss.
Most hospital-based clinical laboratories no long offer quinine testing, making it especially important for clinicals to be familiar with the signs and symptoms of quinine toxicity.
The CFSRE is recommending forensic laboratories include quinine in their routine scope of testing, if they do not do so already.
Quinine and its naturally occurring stereoisomer quinidine are found in the bark of the cinchona tree, originally from South America. They are individually synthesized for pharmaceutical and medical purposes, with both being effective antimalarial drugs. Quinidine is also prescribed as an antiarrhythmic medication, and can be found in bitter food and beverages like teas, lemon and tonic water. Laboratory tests may not distinguish between quinine and quinidine, and their presence may be reported non-specifically as undifferentiated quinine/quinidine.