Pharmacology/Decongestants

Mechanism of Action

Decongestants stimulate the alpha-adrenergic receptors to constrict dilated arteries within the nasal mucosa. This decreases the amount of swelling and formation of mucus in the nose from the common cold, sinusitis, and upper respiratory allergies.

Examples

Afrin is the brand name of oxymetazoline. It is administered nasally and is available in the form of nasal drops, spray or mist.

Neo-Synephrine, Neo-Synephrine II is the brand name for phenylephrine. It is administered nasally in the form of nasal drops and spray or intravenously.

Sudafed is the brand name for pseudoephedrine. It is administered orally in a capsule, tablet, or oral solution.

Zyrtec-D is the brand name for cetirizine-pseudoephedrine. It is administered orally in the form of a tablet.

Allegra-D is the brand name for fexofenadine-pseudoephedrine. It is administered orally in the form of a tablet.

Claritin-D is the brand name for loratadine-pseudoephedrine. It is administered orally in the form of a tablet.

Side Effects

Decongestants may cause stimulation in the central nervous system, increased blood pressure, increased heart rate, insomnia, anxiety, tremor, rhinitis medicamentosa, and headache. Therefore, decongestants should be avoided if patient has diabetes, heart disease, hypertension, hyperthyroidism, prostatic hypertrophy, or Tourette's syndrome. Decongestants are usually combined with antihistamines to decrease the effect of decongestants alone on patients with hypertension. However, combination decongestants cannot completely cancel out those effects.

References

Mizner, James J., and James J. Mizner. Mosby's Review for the Pharmacy Technician Certification Examination. St. Louis: Mosby/Elsevier, 2010.