The DEA seized 5,000 counterfeit pills containing carfentanil, which is an elephant tranquilizer and “not for humans,” the agency said on social media. According to the DEA, it is 10,000 times more potent than morphine. Due to its strength, a “nearly microscopic” amount of it can induce powerful effects, the DEA said. Most concerning is that emergency antidotes for overdoses such as naloxone may not work for Carfentanil users. “Multiple, high doses of naloxone may be required, and even then, effective reversal of an overdose is not guaranteed,” said the DEA.