A Bristol Tennessee Veterinarian Office Has Donated Free Narcan Kits To Area Police K-9 Units. Dr. Mark Riehl Of The Animal Medical Clinic Said Several Police Departments Reached Out To Him Several Months Ago After They Began Coming Across More Dangerous Drugs. He’s Now Offering The Free Kits Valued At $200 Each To Any K-9 Unit In Our Region. The Drug Carfentanil Is 100 Times Stronger Than Street Heroin And Can Be Deadly For A Dog After Just One Sniff Or Touch.