A 32-year-old woman has had hives (uicaria) for 8 weeks. She has not staed any new medications. Her hives are not painful and do not leave behind any pigmentation or other marks when individual resolve (within 24 hours). She has not had respiratory symptoms or lip or tongue swelling. She is frustrated with the amount of pruritis, but does not want to take any medications that make her "sleepy." Which of the following medications would you recommend?