Nasal congestion refers to increased blood flow to the nose and the adjoining paranasal sinuses. It is in response to an inflammatory condition (an infection) or allergic congestion. It generally results in a blocked nose or a stuffy nose due to nasal obstruction. Nasal decongestants are used to relieve these symptoms. Some of the common conditions causing nasal congestion include:
- Allergies like hay fever, pollen
- Common cold or influenza
- Deviated nasal septum
- Infected nasal polyps
Nasal decongestants directly act on the blood vessels and cause vasoconstriction. A vast majority of them are sympathomimetics. They induce vasoconstriction and thus decrease vascular permeability and the resultant inflammation.
Histamine is a local molecule that is implicated in local allergic reactions.
Some nasal decongestants block the action of histamine as well and thus, limit the congestive symptoms. It is particularly helpful in patients of seasonal allergy.
Some nasal decongestants reduce the host response to the allergen/foreign agent. This provides symptomatic relief to patients. Corticosteroids are thus widely used for this purpose. However, they have a doubtful efficacy in the treatment of congestive symptoms.
They are widely available as topical nasal drops, in the form of oral preparations and also as inhalers.
Different Drug Classes:
Indirectly acting sympathomimetics:
- Ephedrine – Indirectly increases the release of norepinephrine to cause vasoconstriction. It is non-selective and low efficacy.
- Levomethamphetamine- (Vicks)
- Pseudoephedrine (Sudafed) – can be given orally.
α-Adrenergic receptor agonists:
- Naphazoline- It is marketed as Privine
- Oxymetazoline-It is marketed as Nasivion and Sinarest
- Xylometazoline- It is marketed as Otrivin
- Beclomethasone dipropionate- (Beconase, QNASL)
- Budesonide- It is marketed as Rhinocort.
Side-Effects and Extra-Nasal Action:
Inhalers are generally preferred over topical preparations since they are easy to self-administer, have a wide surface area of activity and thus have a rapid onset of action. However, there may be initial tingling or burning sensation (especially with drugs like naphazoline). It is mild and transient.
Sustained use may predispose to atrophic rhinitis (due to vascular contraction) and will lead to anosmia (lack of perception of smell).
Long term use of nasal decongestants is not advised as it can lead to desensitization and tachyphylaxis. Thus, the blood vessels no longer contract and there is no significant relief. Besides, prolonged usage of adrenergic agonists may lead to paradoxical nasal congestion. They should not be used for more than 3 days in a row. This condition is called rhinitis medicamentosa. It is more pronounced with sympathetic drugs and corticosteroids. This precludes long-term usage.
Long term corticosteroids may also lead to immunosuppression and lead to opportunistic fungal infections including candidiasis and aspergillosis. They may induce diabetes as well. Hence, they are not the first-line drugs and are only used for severe cases.
Caffeine in coffee can increase the side effects of these medications. Theophylline (used in bronchial asthma), theobromine (in chocolates) can also supplement the activity of the above drugs. Thus, large doses should be avoided.
In patients with systemic hypertension, vasoconstriction can further increase blood pressure. They may face serious side-effects such as throbbing headache, micro-vascular hemorrhages, dizziness, retinal bleed, etc.
Many nasal decongestants should not be taken by individuals who are also taking MAO inhibitors (selegiline and rasagiline). MAO-inhibitors inhibit the degradation of epinephrine and norepinephrine. Along with sympathomimetics, they may precipitate a hypertensive crisis. In patients with an enlarged prostate, it may aggravate the symptoms and cause urinary incontinence.
The CNS effects of the nasal decongestants are variable. They include excitability, restlessness, and insomnia. Thus, they are combined with an anti-histaminic which has a sedative property. However, many fixed dosed combinations are under review by the FDA with respect to actual efficac