Histamine + Anti-Histamine

Question 1

H1 blockers

1st gen
Rx

Answer 1

Chorpheniramine
Diphenydramine
Dimehydrinate

Question 2

H1 Blockers

2nd gen
Rx

Answer 2

Loratadine
Certirizine
Fexofenadine

Question 3

Other Drugs

Rx

Answer 3

Cromolyn Sodium

Question 4

Histidine made from

Answer 4

L-histidine

Question 5

Histamine metabolism

Answer 5

Released from mast cell/basophils, stored w/ heparin/acidic proteins

RAPIDLY broken down to inactive metabolites (MAO-B)

Question 6

Autocoid

Answer 6

Released and act locally

Histamine

ALSO: serotonin, inflammatory modulators

Question 7

Histamine roles

Answer 7

Immune
NT

In periphery widespread: skin/lungs

Question 8

Histamine activates

Answer 8

• Inflammation
• activates acid-producing parietal cells
• NT central/peripheral

Question 9

HIstamine

Reaction type?

Answer 9

Type 1 hypersensitivity IgE

Question 10

H1

Answer 10

Smooth muscle, CNS = up Ca2+

Endothelium = Up NO, cGMP

Question 11

H2

Answer 11

Vascular smooth muscle

Question 12

Why histamine released?

Answer 12

Immunologic (type 1, inflammation)

Mechanical (injury)

Drug effects (opiods, meds)

Question 13

Cromolyn

Answer 13

Blocks histamine release

Question 14

Histamine

Why smooth muscle contraction but vasodilation?

Answer 14

On H1/h2 smooth muscle, Up Ca2+ constrict

On H1 endothelial cell = releases NO, trumps any contraction

Question 15

HIstamine

Peripheral effects

Answer 15

• stimulate primary afferent nerve endigns : itch Pain (h1)

* CNS = NT. (Wakefullness, appetite, body temp)

Question 16

Where can histamine be eaten?

Answer 16

Spoiled scombroid fish

High in histidine –> histamine (bacteria)

S/s: N/V, headache, flushing, sweating
GIVE H1 BLOCKER

Question 17

Anaphylaxis vs Local allergic

cause?

Answer 17

Systemic = most NOT by histamine (other mediators)

*local = histamine (urticaria, allergic rhitinitis)

Question 18

Allergy

*subacute, preventative
*Mast cel stabilizer
Tx?

Answer 18

*Subacute, preventative
Inhaled fluticasone

• Mast cell stabilizer - cromolyn sodium
• stop mast cell degranualtion
• nasal spray

*H1 antihistimines

Question 19

H1 antihistimines

S.E. wakefullness

Answer 19

Some make you awake! (CNS opposite)

Question 20

H1 antihistimines

Work against other inflammatory mediators?

Answer 20

NO

Asthma- leukotrienes

Question 21

Motion sickness?

Answer 21

• **dimenhydrinate
• Diphenhydramine

PROPHYLAXIS

Question 22

1st gen

More anti-chol?

Answer 22

Dyphenhydramine
Dimenhydrinate

LESS chlorpheniramien

Question 23

1st gen h1 blocker

Little specificity = S.E.
(Blocking what?)

OD?

Answer 23

• chol blocker
• dryness, urinary retention, sinus tach
• a-adrenergic blocker/cardiac
  
  • hypoTN/reflex tach, dizziness
• serotonin
• hungry
• H1
• less inflame/itch/sneeze/rhinorrhea
• less CNS neurotransmission/cognitive
• Sedation
• hungry

NO in GLAUCOMA, PROSTATIC HYPERTROPHY

Toxicity after OD = CNS over cardio S.E. – death w/in hours

Question 24

H1 blockers

uses

Answer 24

• *Allergic rhinitis/conjunctivitis (2nd GEN)
• *itching/urticaria (2nd GEN)
• atopic derm (some)
• Drug rxns (NO ANAPHYLAXIS)
• Motion sickness/antiemetic
• NO w/ COLD
• local anesthetic (if allergic to others)
• *Sleep aid (1st GEN)

Question 25

2nd gen H1 blocker Uses

Answer 25

Allergic rhinitis Allergic conjunctivitis Urticaria

Question 26

1st gen h1 blocker Uses

Answer 26

Insomnia | Motion sickness

Question 27

H1 blockers Absorbtion

Answer 27

*rapid, lipid soluble *2nd gen ionized at phys pH, up affinity for PGP (p-glycoprotein = pumps right out of cell) SO METAB IN PERIPHERY, NOT REACHING CNS

Question 28

Histamines effective for sinus congestion?

Answer 28

NO

Question 29

H1 blockers T 1/2?

Answer 29

2nd gen longer

Question 30

H1 blocker Metab

Answer 30

Liver to urine Fexofenadine = liver to bile

Question 31

H1 Blocker Clearance

Answer 31

Renal fexofenadine = bile

Question 32

H1 blocker Pregger?

Answer 32

Cross placenta (no risk in preg) Eliminated in breast milk

Question 33

Fexofenadine transported by

Answer 33

intestinal OATP1A2 = fruit juice inhibition

Question 34

Adverse patient population

Answer 34

Elderly - NO 1st GEN * falls * incontinence * altered consciousness/delirium Infants - NO 1st GEN *adverse effect, fatalities

Question 35

H1 1st gen Daytime use

Answer 35

NOPE Also no w/ alcohol Some children get energy Ex. Benadryl/Sominex (same rx)

Question 36

Antiemetic

Answer 36

Promethazine

Question 37

2nd gen antihistimine w/ possible anti-chol + sedation

Answer 37

Cetirizine

Question 38

H1 blocker Mech

Answer 38

Inverse agonist

Question 39

1st gen, which is sleep aid?

Answer 39

Dyphenhydramine

Question 40

Dyphenhydramine/Dimenhydrinate VS. Chlorpheniramine

Answer 40

D's = more ANTI-CHOL (and more sedation) Chlorpheniramine = OTC cold meds

Question 41

OTC cold meds Rx?

Answer 41

Chlorpheniramine | 1st gen

Question 42

2nd gen antihistimines Themes?

Answer 42

Fexophenadine Loratidine Cetirizine * NO ANTICHOL * NO SEDATION * LITTLE BBB PENETRATION