Decongestants

Antihistamines are used for their drying effect. The older one such as chlorphenamine can cause drowsiness so caution is required if operating machinary.
Adrenergic agents such as ephedrine, pseuodephedrine, oxymetazoline and xylometazoline are used for their decongestive properties.
Topical preparation such as nasal sprays cannot be used for longer periods as they tend to cause rebound congestion. These products may not be suitable for people with high blood pressure, hyperthyoidism, coronary heart disease, diabetes, glaucoma, enlarged prostate and on MAOI therapy.