Antihistamines and Decongestants - Ch 33

produced in response to an allergic reaction or tissue injury

Acts on areas such as the vascular system and smooth muscle, producing dilation of arterioles and an increased permeability of capillaries and venules

localized redness and an increased in the permeability of small blood vessels promoting the escape of fluid from them into the surrounding tissue which also causes swelling! <--- termed an Inflammatory Response!!!

Mast cells release histamen when the body is stimulated by an allergen. (e.g. anaphylactic shock)

• histmaine type 1 = contraction of smooth muscles and dilation of capillaries
• histamine type 2 = the heart and gastric secretions increase
• histamine type 3 = located throughout the nervous system (not sure what happens ..... )

a drug used to block the histmaine cell receptors

These bind nonselectively to central and peripheral type 1 receptors and may result in CNS stimulation or depression (CNS depression usually occurs with higher doses and allows some of these agents to be used for sedation)

• brompheniramine
• chlorpheniramine
• clemastine
• diphenhydramine (Benadryl)
• promethazine (Phenergan)

• azelastine
• cetirzine (Zyrtec)
• desloratadine
• fexofenadine (Allegra)
• levocetirizine
• loratadine (Claritin)

dryness of the mouth, nose, and throat

A drug that reduces swelling of the nasal passages, which, in turn, opens clogged nasal passages and enhances drainage of the sinuses.

• ephedra
• epinephrine
• naphazoline
• oxymetazoline
• phenylephrine
• pseudoephedrine
• tetrahydrozoline
• xylometazoline

• halucinations
• convulsions
• CNS depression

"rebound" nasal congestion: the congestion worsens with use of the drug; relief is felt initially but reoccurs shortly after promting the pt to use the drug more frequently; this perpetuates the the rebound congestion

• Possible Solutions:
• ** nurse may suggestion saline irrigation in nasal passages in place of decongestants
• ** d/c use of deconestants completely or gradually per MD orders
• ** use of oral decongestant instead of topical

Overuse of topical nasal decongestants can cause "rebound" nasal congestion and worsen s/s.

Nasal burning and stinging can occur. If this worsens d/c use of drug and discuss with MD (another drug may be recommended)

if using inhalers; warm in hand before use

if s/s don't improve after 7days seek MD or if it's accompanied with fever

don't let tip of container touch the nose