Palmira Acosta-Mares
All Authors:P. Acosta-Mares1, Z. P. Espinosa-Riquer1, T. Browne Jr.2, S. L. Cruz1. 1Department of Pharmacobiology, Cinvestav, Mexico; 2Colombo Plan Secretariat, Drug Advisory Program, Sri Lanka
Background
Pharmacologically active adulterants are added to commonly misused drugs to mimic, alter, or potentiate their effects. This practice represents a public health risk due to unexpected side effects. Caffeine is a widely consumed psychostimulant generally devoid of adverse effects at the doses used in commercial products. In addition, caffeine is a commonly used adulterant of other psychostimulants like methamphetamine (METH). Although caffeine can mimic, to a certain extent, METH’s stimulant actions, the pharmacological effects of this particular combination have not been well studied. This work analyzes the lethal and locomotor effects of METH plus caffeine.
Methods
We used Swiss Webster male mice (6-8 weeks of age) to test the locomotor effects of low METH and caffeine doses (0.3 mg/kg and 177 mg/kg, i.p., respectively), alone or in combination, in the open-field test. We also calculated the lethal dose at 10% (LD10) of each drug and tested them in combination.
Results
Both methamphetamine and caffeine increased locomotor activity by themselves and produced additive effects in combination. Coadministration of the LD10 of methamphetamine (5.6 mg/kg) and the LD10 of caffeine (177 mg/kg) produced the death of 70% of the population, showing that potentiation occurred.
Conclusions
The effects of combining caffeine with METH depend on the doses of each compound and the effect under study. Our results suggest that consuming methamphetamine adulterated with caffeine may increase the risk of fatal overdose.