BOTANICAL MUSEUM LEAFLETS VoL. 26, No. 5 
May 30, 1978 
COCAINE IN BLOOD OF COCA CHEWERS 
seo 
AND T. PLOWMAN*** 
Although the non-medical use of cocaine, either by sniffing 
or injection, is considered harmful by many medical authori- 
ties, there still is controversy as to whether the chewing of coca 
leaves, as practised by South American Indians, is detrimental 
or not. Experimental evidence on coca chewing gathered sci- 
entifically in the field has not previously been substantiated by 
measurements of blood levels of cocaine. 
During Phase VII of the Alpha-Helix Amazon Expedition 
1976-1977, we had occasion to study two methods of adminis- 
tration of coca leaves and to determine the amount of cocaine 
in blood versus time by an unequivocal method of analysis. 
Whole coca leaves (Erythroxylum Coca Lam.) were obtained 
from Pisac, Department of Cuzco, Peru. Coca powder (pul- 
verized leaves of E. Coca mixed with Cecropia leaf ash) was 
prepared by Witoto Indians of the Rio Ampiyacu, Department 
of Loreto, Peru, according to the custom of the region. 
Coca leaves and powder (5-10 g.) were taken orally by 
human subjects in the same way that South American natives 
do. The cocaine, as measured by mass fragmentography, per- 
sisted in the plasma for more than seven hours and reached 
concentrations from 10 to 150 ng/ml at 0.38 to 1.95 hours. 
Half-lives of the elimination of cocaine have been calculated 
ranging from 1.0 to 1.9 hours. The absorption half-lives ranged 
from 0.2 to 0.6 hours (see Table 1). 
The stimulating effect obtained seems to be well correlated 
*Department of Toxicology, Swedish Medical Research Council, Karolinska Institu- 
tet, S-104 01, Stockholm, Sweden. 
**Institute of Plant Biology and Physiology, University of Lausanne, CH-1005 Laus- 
anne, Switzerland. 
*** Atkins Research Fellow in Economic Botany, Botanical Museum of Harvard 
University. 
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