These are a agonists which on topical application as dilute solution (0.05-0.1%) produce local vasoconstriction. The imidazoline compounds- naphazoline, xylometazoline and oxymetazoline are relatively selective a2 agonists (like clonidine). They have a longer duration of action (12 hrs) than ephedrine. After congestion is claimed to be less than with ephedrine or phenylephrine. May cause initial stinging sensation (specially naphazoline).
Indications
Nasal congestion.
Dosage
Instill 2-3 drops into each nostril.
Contra-Indications
Pregnancy, glaucoma.
Special Precautions
Prolong use to be avoided as atrophic rhinitis & anosmia can occur due to persistant vasoconstriction.Hypertensives. C.N.S. depression.
Side Effects
Stinging sensation, sneezing, dryness of mouth & throat, rebound congestion, mild burning.
