Theoretically, if the side effects could be properly balanced, the sleepiness caused by antihistamines could be cancelled by the stimulation of decongestants. For instance, one might take the antihistamine only at night and take the decongestant alone in the daytime. Alternatively, you could take them together, increasing the dosage of antihistamine at night (while decreasing the decongestant dose) and then doing the opposite for daytime use. Since no one reacts exactly the same as another to drug side effects, you may wish to adjust the time of day the medications are taken until you find the combination that works best.
Antihistamines/decongestants: Many pharmaceutical companies have combined antihistamines and decongestants together in one pill. Typical combinations include (brand names): Actifed®*, .®*, Chlor-Trimeton D®*, Claritin D®, Contac®*, CoPyronil 2®*, Deconamine®, Demazin®*, Dimetapp®*, Drixoral®*, Isoclor®*, Nolamine®, Novafed A®, Ornade®, Sudafed Plus®, Tavist D®*, Triaminic®*, and Trinalin®.
Mortuaire, G., de Gabory, L., François, M., Massé, G., Bloch, F., Brion, N., ... Serrano, E. Rebound congestion and rhinitis medicamentosa: Nasal decongestants in clinical practice. (2013, June 1). Critical review of the literature by a medical panel. European Annals of Otorhinolaryngology, Head and Neck Diseases , 130(3), 137-144. Retrieved from https:///#!/content/playContent/1--S1879729612001378?returnurl=http:%2F%%2Fretrieve%2Fpii%2FS1879729612001378%3Fshowall%3Dtrue&referrer=https:%2F%2F .
Saline solutions used in nasal irrigation reduce inflammation through osmosis. Swelling is a major factor in sinus dysfunction. Removal of mucus plays an important role in sinus health, and nasal irrigation facilitates this by flushing out thickened mucus that cannot be handled by the cilia .   improving mucociliary clearance and also removing infected material.  Damage to the mucociliary transport system is an important factor in the development of sinonasal diseases, leading to a stasis of mucus.  The numerous proteins found in nasal mucus include inflammatory mediators , defensins and many whose function is not understood.