What medication did Bob Rushwood use to cause Holly's death in the novel, The Whole Enchilada?

Loquin is an antibiotic that had been pulled off the market after it was discovered that it caused several severe side effects in some patients including terrible nightmares and hallucinations, which a number of the guests at Drew and Arch’s 17th birthday party suffer from later that night. Loquin is also known to causes heart attacks in people who have an irregular S-T interval in their heartbeat, a condition that Goldy discovers Holly suffered from, and the toxicology tests shows traces of the antibiotic in Holly’s blood. Bob Rushwood, who knew about Holly’s heart condition, had taken Loquin for a sinus infection shortly before it was pulled off the market. He kept some of the antibiotic after the sinus infection cleared up, and sprinkled enough of the ground-up tablets onto the chili relleno torta he knew Holly would eat at Drew and Arch’s party to kill her.