acrivastine molecule, structural chemical formula, ball-and-stick model, image h1-receptor antagonist antihistamine

acrivastine h1receptor antagonist antihistamine upper respiratory combinations molecule molecular structure chemical formula isolated model c22h24n2o2 atom illustration disease flu health care illness medication medicine oral prescription product seasonal treatment congestion sneeze tablets cold allergic rhinitis duact hay fever pollen allergy pseudo ephedrine agent bond carbon chemistry laboratory liquid oxygen ring science signs structural ball- -stick image h1-receptor ball- -stick antihistamine