Drugs affecting the respiratory system

Question 1

Drugs affect respi syrem? 4 types

Answer 1

1. Antihistamine
2. decongestants
3. antitussives
4. expectorants

Question 2

Understand the cold.

Answer 2

Virus invade mucosa -> URI -> inflamme -> excessive mucus -> pharyx -> esophagus & lower resp tract -> sorethroat, cough, upper stomach.

Question 3

irritate nasak mucosa trigger sneezing

Answer 3

mucosal irritation -> inflamme & vasoactive -> dilate small blood vessel @sinus -> nasal congest

Question 4

URTI: tx common cold

Answer 4

• diff to identify(virus/bac)
• empiric therapy
• antiviral/antibac may be use

Question 5

Antihistamines=

Answer 5

compete w histamine for specific receptor.

histamine rceptor:
H1 histamine
H2 histamine

MOA:
bind H1 blocker to histamine receptor  -> prevent histmine stimulate:
-vasodilate
-increase gastro & respi secretion
-increase capillary permeability

SMOOTH MUSCLE (exocrine glands):
histamine effects:
-stimulate salivary, gastric, lacrimal, bronchial secretion
(antihistamine - prevent these)

IMMUNE SYSTEM:
release substance associate allergic

histamine effects:
mast cell release histamine -> allergic

antihistamine effects:
bind histamine receptor -> prevent response

SKIN:
Block capillary permeability, itch, flare formation

anticholinergic:
drying (nasal)
sedative

therapeutic use?
nasal alg
rhinitis
alg reaction
motion sickness
sleep disorder

side effects?

• anticholinergic(drying-common)
• dry mouth
• diff urinate
• consti
• change vision
• drowsiness

Question 6

Decongestants

Answer 6

Nasal congestion -> excessive nasal secretion

-inflamme nasal mucosa
Causes:
-Allergic
-URI

Decongestant 2 main types: Adrenergics
PO, inhal/topical

Topical nasal decongestants
Adrenergics:
-ephedrine (Vicks) naphazoline(privone)
-oxymetazoline (afrin) phenylephrine (neo synephrine)

Intranasal setroids:
-beclomethasone dipropionate

therapeutic:

• rhinitis
• common cold
• sinus
• hay fever
• alg

MOA:
action- blood vessel surrounding nasal sinus

nasal steroids:

• anti inflamme
• turn off immune cell
• decrease inflamme -> decrease congestion

Question 7

Antitussive

Answer 7

Cough physiology:
-Resp secretion & foreign naturally remove by cough reflex

• Induce cough & expectoration
• irritate sensory receptor @resp tract

2 basic cough
-productive cough

-Non productive cough (Dry)

Benefit of cough
-remove excess secretion, harmful foreign

therapeutic:
opoid / nonopioid
-use only for NONPRODUCTIVE coughs

MOA -
1. opioid:
suppress cough refelx @cough center in medulla
(codein)

2. Non opioid:
   suppress cough by numb the stretch receptor @respi tract -> prevent cough refelx stimulate
   (benzonatate, dextromethorphan=vicks)

side effect:
Dex=vicks
dorwsiness, nausea

opioids- sedation, nausea, lightheaded, constipate

Question 8

Expectorants=

Answer 8

Removal of mucus

• reduce viscosity
• disintegrate破碎 secretion

MOA:
direct/reflex stimulation -> thinner mucus

Direct =
secretory gland stimulate -> increase production respi tract fluid

Reflex =
Agent irritate GI tract-> thinning respi tract secretion

Common side effect?
Guaifenesin
-nausea, gastric

Nursing implication?
1. use in caution elderly, asthma pt/ respi insufficiency

2. should tk more fluid -> loosen secretion
3. report if fever, cough (if > 1wks)

Question 9

Bronchodilator

Answer 9

Xanthine derivative
(Theophylline)
MOA:
-increase level of energy-producing cAMP (cyclic adenosine monophosphate)

-inhibit phosphodiesterase (ezyme break down cAMP)

Result: decrease cAMP, borchodilate -> increase airflow

side effect:

• nausea
• Reflux
• tachy, extrasystole, palpate
• increase urination