TEWKSBURY, Mass. — A Massachusetts district attorney and police chief are hosting a free training on how to administer the drug overdose antidote naloxone.District Attorney Marian Ryan and Tewksbury Police Chief Timothy Sheehan will host the training on Monday at the Tewksbury Public Library. Doses of naloxone will be handed out to participants.Naloxone, which is often referred to by the brand name Narcan, can restore a person's breathing after it is injected or sprayed in the nostrils, quickly reviving overdose victims.