Histamine is produced by basophils and mast cells during immune responses. It binds to H1-H4 receptors, causing effects like vasodilation, bronchioconstriction, and increased gastric acid. Anaphylactic shock results from severe drops in blood pressure and impaired breathing from vasodilation and bronchioconstriction. Epinephrine is used to treat it. Antihistamines compete with histamine at receptors to treat allergies and other conditions. Antitussives suppress coughing through opioid or non-opioid mechanisms. Decongestants stimulate alpha receptors to constrict nasal passages. Expectorants thin mucus to make coughing up secretions easier.

1. Snotty snotwell

2. N N
NH2
H
1
2
3
45
Histamine
As part of an immune response to foreign pathogens,
histamine is produced
by basophils(blood) and by mast cells(tissues) when
contacting the antigen.
Mast cells found at site of likely injury…nose,mouth,
feet, GI tract, respiratory,blood vessels.
Histamine will bind with certain receptors on cells to
give different results.
Histamine is a neurotransmitter that hits H1 H2 H3 or H4

3. H1 receptor found in smooth muscle, endothelial cells.
histamine will cause increase of permeability of
vessel wall(to reach infection) and
brochoconstriction, runny nose.
H2 receptor found in stomach and vascular smooth
muscle cells histamine will cause gastric acid increase
and vasodilation.
H3 receptor found in CNS tissue. Histamine yields
decreased other neurotransmitters.
H4 receptor found in basophils,bone marrow.
deals with chemotaxis.

4. Two main effects of anaphylactic shock on the body
are severe drops in blood pressure and impaired
respiration.
The drastic drop in blood pressure
develops from the severe peripheral vasodilation
and the increased permeability of the capillaries.
The impaired breathing arises from
bronchoconstriction. The anaphylactic reaction
occurs very rapidly after the introduction of the
antigen into the patient.
Unless prompt action is taken by medically trained
personnel, the patient will die in a matter of minutes.
The drug used for anaphylactic shock is epinephrine.

5. antihistamines
Action- competes with histamine due to similar
structure. for treatment of allergies, insomnia, rash,
and prophylaxis for drug allergies
Adverse reactions- drying up body fluids, drowsiness,
and hyperactivity in some children
Considerations- these are the antidote for overdose in
anitpsychotic meds, and do not mix with alcohol-
synergistic effect

6. Some antihistamine drugs
Zyrtec- allergies
Allergra- allergies
Benadryl- allergies
Anti-vert- dizziness
Phenergan- vomiting

7. antitussives
action- supresses cough
 Indicated for nonproductive coughs!
Opioid and non-opioid (narcotic and non-narcotic)
Mechanism of Action--
Opioids---Suppress the cough reflex by direct action
on the cough center in the medulla
examples: codeine (Robitussin A-C, Dimetane- DC)
Hydrocodone
Onset: 15-30 min

8. Non-opioids/non-narcotic (less effective)
Suppress the cough reflex by anesthetizing the
stretch receptors in the respiratory tract and
preventing the cough reflex from being stimulated
by the medulla center in the brain
examples: benzonatate (Tessalon Perles)
dextromethrophan (Vicks Formula 44, Robitussin-DM)
Onset: 15-30 min
Reactions- depression, light-headedness
Considerations- dextromethorphan reacts with
MAOI’s(antidepressants)
due to the potential for seratonin syndrome, which is a potentially
life-threatening
condition that can occur rapidly, due to a buildup of an excessive
amount of serotonin
 benzonatate must be swallowed not chewed. may cause
choking feeling, chest painn or numbness, hallucination, confusion.

9. antitussives
Tesselon perles
Robitussin
Benadryl
Codeine
hydrocodone

10. decongestants
Action- stimulates alpha adrenergic receptor to
constrict arteries within the nasal mucosa. many cells
have these receptors, to stimulate sympathetic NS.
Treats congestion from cold, sinusitis and infections
Reactions- increased blood pressure, increased heart
rate, insomnia, anxiety, tremors, rebound effect
Considerations- should be avoided by patient who
have DM, heart disease, enlarged prostate, tourette’s
syndrome

11. decongestants
Afrin----oxymetazoline
Sudafed--pseudoephedrine
Zyrtec---cetirizine-pseud….
allegra--fexofenadine-psedo…
claritin---loratadine-pseu….

12. expectorants
Action- decrease thickness of mucus to remove or
cough out of the lungs. increase bronchial secretion
Reactions- vomiting and GI distress
Special considerations- drink plenty of water

13. Expectorants
guaifenesin----Robitussin
Mucinex-D----guaifenesin/pseudoephedrine
Robutussin AC---guaifenesin/codeine