Side effects
People with high blood pressure, diabetes and cardiovascular disease should use decongestants sparingly, if at all. Decongestants can constrict veins and reduce the effectiveness of blood pressure medications. Furthermore, decongestants may cause convulsions by stimulating the central nervous system. People older than 60 are particularly prone to convulsions as well as hallucinations. Pregnant women should also avoid decongestants since safety guidelines for them have not been established.
Even young, healthy people can get very jittery and shaky while taking these products. Try avoiding coffee or other forms of caffeine when taking a decongestant. If these symptoms persist, it would be wise to consult an allergist or other sinus specialists, such as an otolaryngologist (ear, nose and throat doctor).
Use of topical decongestants such as phenylephrine (Afrin, Neo-Synephrine, Vicks Sinex) or oxymetazoline (Afrin Original Nasal Spray, Neo-Synephrine 12 hour) for more than three to four days may cause a rebound effect that can be worse than the initial symptoms. Prolonged use may additionally make it more difficult to stop using these medications. When people abuse these topical decongestants, they may irreversibly damage the nasal mucous membranes.
Post-Nasal Drip: This symptom is very difficult to treat. The causes can be an allergy, infection or a nasal structural abnormality. Antihistamine-decongestant products are the OTC treatment of choice. If the drip is particularly bad, one can add an OTC antihistamine to help dry the drip further. I would especially recommend this at night when being sleepy is not as big of an issue. I would also recommend, however, seeing an allergy or sinus specialist for a more specific diagnosis in order to start the best treatment.
