If there’s a possibility you might have a work-related drug test when you return home from Peru, be careful with any form of coca consumption while on holiday.
Chewing coca leaves and drinking coca tea is common in Peru, especially in the Andes. It is also legal and is frequently recommended as a means to prevent altitude sickness (although its effectiveness is unproven).
The problem, however, is the coca alkaloid content of coca, which may cause a drug test to show positive for cocaine.
In 1995, the Forensic Science International published a study by Jenkins, Llosa, Montoya and Cone that warned of the potential risks of positive drug tests after consuming coca tea:
This study has shown that consumption of one cup of coca tea results in detectable concentrations of cocaine metabolites in the urine for at least 20 h. Therefore, coca tea drinkers may test positive in a urine drug test for cocaine. (“Identification and quantitation of alkaloids in coca tea”; Jenkins et al; 1995)
According to Amitava Dasgupta in Beating Drug Tests and Defending Positive Results: A Toxicologist’s Perspective, residual cocaine “may still be present after “de-cocainization” of coca leaves.” Even coca teas that are supposedly free of cocaine may result in a positive drug test.
Dasgupta recommends greater caution regarding coca teas and drug tests: “Because of the possibility of testing positive for cocaine following drinking coca tea, it is advisable to avoid any herbal tea originating from South America at least for a few weeks prior to any workplace drug testing.”
Less research seems to exist about the precise risks of chewing coca leaves (rather than drinking them in a tea) prior to a drug test. If a workplace drug test is a possibility, however, you should certainly avoid chewing coca leaves in the weeks leading up to the potential test.
- “Identification and quantitation of alkaloids in coca tea” -- Forensic Science International; Jenkins et al; 1995
- Beating Drug Tests and Defending Positive Results: A Toxicologist’s Perspective -- Amitava Dasgupta; Humana Press; 2010