Topical Nasal Decongestants

The nasal mucosa is sensitive to changes in atmospheric temperature and humidity and these alone may cause slight nasal congestion. The nose and nasal sinuses produce a litre of mucus in 24 hours and much of this finds its way silently into the stomach via the nasopharynx. Slight changes in the nasal airway, accompanied by an awareness of mucus passing along the nasopharynx causes some patients to be inaccurately diagnosed as suffering from chronic sinusitis. These symptoms are particularly noticeable in the later stages of the common cold.

• Assess the patient for an underlying cause e.g. polyps.
• Clarify what over the counter preparations the patient has already used.
• Be sure the patient is not on a monoamine oxidase inhibitor.
• Inhalation of warm moist air is useful in the treatment of symptoms of acute infective conditions. The addition of volatile substances such as menthol and eucalyptus may encourage the use of warm moist air.

• Topical nasal decongestants:
  • Sodium chloride 0.9% given as nasal drops may relieve nasal congestion by helping to liquefy mucous secretions. It is very safe, but the efficacy over placebo is unproven.¹
  • Corticosteroid nasal drops are used to shrink nasal polyps. Intranasal steroid therapy improves allergic rhinitis symptoms and is particularly effective in relieving congestion, by attenuating nasal hyperresponsiveness.²
  • Decongestants contain sympathomimetics, which exert their effect by vasoconstriction of the mucosal blood vessels. This reduces oedema of the nasal mucosa. Ephedrine nasal drops are the safest sympathomimetic preparation and can give relief for several hours. The more potent sympathomimetic drugs oxymetazoline and xylometazoline are more likely to cause a rebound effect.
  • Antihistamine-decongestant combinations
• Antihistamines reduce rhinorrhoea and sneezing but are usually less effective for nasal congestion.
• Systemic decongestants may not be as effective as preparations for local application but they do not give rise to rebound nasal congestion on withdrawal. Pseudoephedrine is available over-the-counter and it has few sympathomimetic effects.

Symptoms of nasal congestion associated with vasomotor rhinitis and the common cold can be relieved by the short-term use (usually not longer than 7 days) of decongestant nasal drops and sprays.

They all contain sympathomimetic drugs. They are of limited value because they can give rise to a rebound congestion - rhinitis medicamentosa - on withdrawal. This is due to a secondary vasodilation, with a subsequent temporary worsening of symptoms. This may lead to further use and a negative spiral of events.

Topical versus systemic sympathomimetics³

One study objectively measured the decongestive capacity of topical xylometazoline and oral pseudoephedrine in normal subjects and patients with chronic sinusitis:

• The topical preparation showed a 37.3% reduction in nasal airway resistance of healthy subjects for 8 hours, unlike the systemic preparation which showed no clear and long-lasting beneficial effect.
• Interestingly, neither showed any decongestive effect on the sinus mucosa.

Topical versus systemic decongestants⁴

Long-acting oral cetirizine and pseudoephedrine were compared to aqueous nasal spray budesonide:

• Cetirizine/pseudoephedrine efficacy was statistically superior to budesonide in the immediate (post-exposure to allergen) management of nasal congestion.
• However, the efficacy of cetirizine/pseudoephedrine was similar to that of budesonide from the end of day 1 up to day 4, when individuals had returned home.

Antihistamine-decongestant combinations⁵

• These have been found to be significantly more effective than placebo.

Topical nasal antihistamines have superior effects to oral antihistamines for rhinitis symptoms but do not reduce symptoms at other sites e.g. eyes.⁶ They are fast acting (less than 15 minutes) so are a useful 'rescue'.

General principles are the same as for adults.

• In the baby or very young child, do not attempt to inhale steam from boiling water. Suggest sitting in a steamy bathroom.
• When nasal congestion interferes with suckling, 1-2 drops of normal saline instilled (via syringe if infant very small) in each nostril prior to feeding is helpful.
• Aromatic inhalations should not be used in infants less than three months old. Use with care in older babies and young children. A single drop on a tissue in the room is sufficient.
• Epinephrine nasal drops are the least likely to cause rebound congestion.
• Two studies showed no difference between antihistamine-decongestant combinations and placebo.⁵ Antihistamines have been shown to be no more effective than placebo for children.

• Sympathomimetic preparations may cause a hypertensive crisis if used during treatment with a monoamine-oxidase inhibitor, including moclobemide.
• Systemic decongestants should be used with caution in:
  • Diabetes
  • Hypertension
  • Hyperthyroidism
  • Raised intra-ocular pressure
  • Prostatic hypertrophy
  • Hepatic impairment
  • Renal impairment
  • Ischaemic heart disease

Other cautions

• Systemic compound preparations containing pseudoephedrine are available over the counter. Many preparations also contain antihistamines, which may cause drowsiness and affect the ability to drive or operate machinery.
• Pregnancy; interventions are often not used in pregnancy because of alarming information in drug labels:
  • Low-risk therapies include intranasal sodium cromoglycate, beclometasone, budesonide and first-generation antihistamines.
  • A meta-analysis of the safety of first-generation antihistamines in pregnancy showed 200,000 first trimester exposures had no increased teratogenic risk.
  • Decongestants have not been shown to affect the fetus and can be used for short-term relief when no other alternatives are available.
  • Intranasal corticosteroids have not been associated with an increase in congenital malformations in humans. There are, however, very few studies in humans.⁷

• Antihistamines differ in their duration of action and incidence of drowsiness and antimuscarinic effects. Many older antihistamines are relatively short acting but some (e.g. promethazine) act for up to 12 hours, while most of the newer non-sedating antihistamines are long acting.