PARSIPPANY, N.J. — Reckitt Benckiser recently line-extended its Mucinex franchise into the year-round allergy sector with Mucinex Allergy. “More than 75% of Mucinex users also take an allergy treatment,” said Heather Allen, Reckitt Benckiser EVP category development. Mucinex Allergy is formulated with fexofenadine hydrochloride, the generic equivalent to Allegra, a $200 million brand.