Tequila mystery.

jcjms_  -  August 10, 2022

Felix and Jonathan went to a bar. Both ordered tequila to drink. Felix had a doctors appointment later, just a general health check. So he finished his tequila quickly, ordered and drank another one in the time that it took Jonathan to finish just one. Soon after this, Jonathan dropped dead to the floor, but Felix was totally unharmed. The police ruled it a murder, because they found out, that both the tequilas were poisoned.

How did Felix survive?