(CNN)The Drug Enforcement Administration said Thursday it made 810 arrests and seized more than 1.8 million fake pills during a two-month sweep to stem the flow of counterfeit medications containing the synthetic opioid fentanyl. The lethal tablets are fueling a surge in US drug-overdose deaths in recent years, and largely are trafficked from Mexico, where drug cartels produce the tablets from precursor chemicals imported from China,... ...DEA Administrator Anne Milgram said the agency is working to shut wide distribution networks selling tablets that look like name-brand prescription medications such as Xanax and Percocet. "DEA laboratory testing reveals that today, four...