A decongestant is a medication that relieve the stuffy-nose feeling caused by an illness, most commonly the flu, a cold or allergies.In other words decongestant shrinks the swollen membranes in the nose and makes it easier to breath.
Decongestants can be taken orally or by nasal spray. Decongestant nasal sprays should not be used for more than five days without the doctor's advice.Decongestants should not be used by patients with high blood pressure(hypertension) unless under doctor's supervision.
The vast majority of decongestants act via enhancing nor epinephrine or epinephrine or adrenergic activity by stimulating alpha adrenergic receptors.This includes vasoconstriction of blood vessels in the nose, throat,and para nasal sinuses,which results in reduced inflammation (swelling) and mucous formation in these areas.
The active ingredients in most ingested decongestants are Psuedoepedrine or phenylephrine.Pseudoephedrine acts indirectly on the adrenergic receptor system, whereas phenylephrine is a direct agonist.Usage of Pseudoephedrine is banned in diffrent countries including India.