Sympathomimetic And Antihist

Front 1

physiology of histamine

Back 1

-synthesis: from histidine
-storage: mast cells & basophils
-sites: entire body, around bl vessels
-actions:
1. bronchial smooth m.-> constricts
2. blood vessels- dilate
3. gastric acid secretion
4. nervous system (stim pain, itching in nerve endings)

Front 2

Histamine type 1 receptors

Back 2

-in smooth m., endothelium, and brain and mediates allergic response
-vasodilation, inc cap perm--> redness, swelling; bronchoconstriction; flare response and itching

Front 3

Histamine 2 receptors

Back 3

-gastric mucosa, mast cells, cardiac and brain
-binding to parietal cells increases gastric acid secretion
-can inc contractility and HR

Front 4

common antigens which cause type I hypersensitivity rxns

Back 4

1. pollen
2. food
3. drugs (PCN, salicylateS)
4. insect products
5. animal hair

Front 5

Histamin-1 Antagonists

Back 5

-competitive antagonism at hist1 receptors
-used for allergies, better for prevention (also for motion sickness, anti-nausea, anti-emetic)
-first gen: cross BBB and sedating (benedryl)
-second gen: less sedating

Front 6

first gen antihistamines

Back 6

1. Diphenhydramine HCL (Benadryl)- PO, IV, IM
-allergies, sedation, some anticholinergic effects- can be drying (careful w/BPH, glaucoma)
2. Dimenhydrinate (Dramamine)
-motion sickness prevention, vestibular disturbances
-some anticholinergic effects

Front 7

first gen antihitamines cont.

Back 7

3. Hydroxyzine HCL (atarax) and Vistaril (pamoate)
-sedative and mild anxiolytic properties, good for severe itching
4. Meclizine HCL (antivert) (OTC)
-to tx vestibular disturbances

Front 8

first gen antihistamines cont.

Back 8

5. Promethazine (phenergan)
-used for antiemetic, sedating
-prevention and tx of N/V
-PO, parenteral, transdermal
-(dirty drug)alpha blocking--> causes orthostatic HTN), dopamine blocking
6. Cyproheptadine (Pariactin) (old, rarely used)
-used to enhance appetite
-serotonin blocking
7. Doxepin- very potent
-tricyclic antidepressant

Front 9

pharmacology of first generations

Back 9

-well-absorbed for GI tract
-variable half lives
-may induce hepatic microsomal enzymes
-excreted in urine

Front 10

second gen antihistamines

Back 10

-peripherally-acting and non-sedating (dont cross BBB)
-little to no anticholinergic effects
-used for tx of allergic rhinitis, chronic urticaria

Front 11

types of 2nd gen histamines

Back 11

1. Cetirizine (Zyrtec) (most sedating)
2. Fexofenadine (Allegra) (least sedating)
3. Loratidine (Claritin)
4. Desloratine (Clarinex)
-used mostly for allergic rhinitis
-most can be combined with a D (decongestant)

Front 12

pharmacology of 2nd gen antihistamines

Back 12

-hepatic metabolism
-urinary excretion
-Qd to BID dosing
-clarinex has longest half life

Front 13

AE of first gen antihistamines

Back 13

1. sedation, but may activate kids
2. change in appetite, N/V
3. dry mouth and other anticholinergic effects

Front 14

AE of 2nd gen antihistamines

Back 14

1. Less sedation
2. little to no anticholinergic
3. headache and nausea

Front 15

Sympathomimetics MOA

Back 15

-act topically and systemically on adrenergic receptors to produce vasoconstriction and shrink nasal mucosa (USED FOR THEIR DECONGESTANT EFFECTS)
-alpha 1 (on blood vessels) agonists

Front 16

Topical nasal decongestants

Back 16

1. short acting: Phenylephrine, up to 4 hrs (can cause rebound congestion)
2. Intermediate: Naphazoline, Tetrahydrolozine, 4-6 hrs
3. Long acting: Oxymetazoline, xylometazoline
-dont use more than 3-4 days!

Front 17

side effects of topical decongestants

Back 17

-do not use for more than 5 days because of rebound congestion and rhinitis medicamentosa (phenylephrine is notorious)
-burning, stinging, dryness of nasal mucosa
-use only when necessary at lowest dose
-role: short term use for common cold w/severe nasal congestion

Front 18

systemic decongestants

Back 18

-pseudoephedrine most common
-alpha and beta agonist activity
-often in combo with 2nd gen antihist for allergic rhinitis w/nasal congestion
claritin D, allegra D, zyrtec D

Front 19

side effects of systemic decongestants

Back 19

1. mild CNS stimulation
2. high doses can inc pulse and BP
3. caution in pts with HTN and BPH
4. caution in preg
5. behind counter

Front 20

Guaifensesin

Back 20

-helps loosen phlegm and bronchial secretions to make coughs more productive (mucolytic)
-used for chronic bronchitis, common cold and bronchitis
-robitussin OTC
-rx: Duratuss, Humibid,

Front 21

side effects guaifenesin

Back 21

-well-tolerated
-N/V are most common side effects
-be aware of combo products and their side effects
-preg category C

Front 22

Nasal corticosteroids

Back 22

-excellent therapy for seasonal and perennial rhinitis
-MOA: reduce inflammation, block mediator release, suppress chemotaxis of neutrophils, reduce edema
-peak response several days
-AE: minor local effects, funny taste

Front 23

nasal corticosteroids types

Back 23

1. Beclomethasone dipropionate
2. Budesonide
3. Flunisolide
4. Fluticasone
5. mometasone furoate
6. Triamcinolone acetonide

Front 24

leukotriene receptor antagonists

Back 24

Montelukast (Singulair) Po
-is approved for the treatment of allergic rhinitis
-also used for maintenance in chronic asthma

Front 25

2 new allergy meds approved

Back 25

1. Veramyst- nasal spray containing an aqueous suspension of micronized fluticasone furoate
2. Xyzal- oral H1 blocker for seasonal and perinnial allergic rhinitis and chronic urticaria