Decongestants are medicines that relieve congestion by reducing swelling, inflammation and mucus formation within the nasal passages or the eye. They have no other effect on symptoms such as a runny nose or sneezing.
Decongestants may be taken orally to help relieve congestion that is affecting the nose, sinuses, and eyes or sprayed directly in the nose or instilled in the eye for a more local effect.
The inside of the nose is lined with small blood vessels. Blood flow is increased to these blood vessels when our immune system detects the presence of an allergen (such as a virus or pollen). This causes swelling within the blood vessels which can block the nasal passageway, making nasal inhalation difficult. In addition, mucous glands within the nose secrete more mucus to trap the allergen which also contributes to nasal congestion and creates a sensation of “stuffiness”.
Most decongestants work by activating alpha-adrenergic receptors either by binding directly to them ...