Allergic Rhinitis 2: Pharm Management Flashcards

1
Q

AR - Antihistamines

What is Histamine?

A

Histamine is found in most tissues
•Higher concentration in tissues exposed to outside world (lungs, skin, GIT)
•Released from mast cells during allergic/inflammatory reactions

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2
Q

AR - Antihistamines

Name the 4 types of histamine receptors?

A

H 1 , H 2 , H 3 , and H 4

H 1 receptors are the site of action for antihistamines

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3
Q

AR - Antihistamines

List the histamine binding to H 1 receptors causes

A
  • Smooth muscles to contract in the bronchi
  • Dilation of blood vessels and increased permeability
  • Increases heart rate and cardiac output
  • Reddening of the skin, itch, wheal with a surrounding flare (hives)
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4
Q

AR - Antihistamines - PK

What are the effects from Antihistamines - PK

A
  • Absorbed well from the GIT
  • Peak plasma concentration achieved in 2-3 hrs
  • Duration of effect varies (1st & 2nd generation)
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5
Q

AR - Antihistamines - 1st gen

List the effects from 1st gen

A
  • Rapid onset but short duration of action (short T 1⁄2)
  • Poorly selective for H 1 receptors
  • Highly lipophilic 🡪 Penetrate readily into the brain (sedation)
  • Have effects on muscarinic receptors (anticholinergic effects)
  • Decrease rhinorrhea but can thicken mucus secretions
  • Duration of effect varies: Chlorpheniramine maleate = 24 hrs & Diphenhydramine HCI = 12 hrs
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6
Q

AR - Antihistamines - 1st gen

List the side effects from 1st gen

A

• Anticholinergic: dry mouth and nasal passages, difficulty voiding urine, constipation, tachycardia
Note: elderly more susceptible to anticholinergic
effects

• Central H 1 receptor effects: sedation and cognitive and/or performance impairment:
- Lower work/academic performance, slowed reaction
times, decreased visual-motor coordination
- Even if taken at bedtime

• Can have paradoxical excitation in children

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7
Q

AR - Antihistamines - 1st gen

List the precautions from 1st gen

A

• Drug-Disease interactions
◦ Narrow-angle glaucoma
◦ Symptomatic prostatic hypertrophy
◦ Bladder-neck obstruction

• Drug-Drug interactions
◦ CNS depressants: alcohol, sedatives
◦ Drugs with anticholinergic side-effects: TCAs
◦ Drugs metabolized by CYP2D6 may be affected

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8
Q

AR - Antihistamines - 2nd gen

List the effects from 2nd gen

A

• Drug of choice for treatment of mild allergic rhinitis
• Rapid absorption from GIT
• Less lipophilic 🡪 limited penetration of BBB
• Highly selective for H 1 receptors
• Minimal anticholinergic effects
• Longer duration of action than 1 st generation
• All similar in efficacy
• Less effective than intranasal corticosteroids
especially for congestion:
- Desloratadine, fexofenadine, and cetirizine have shown modest improvement in congestion

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9
Q

AR - Antihistamines - 2nd gen

List the duration of effects from 2nd gen

A
  • Cetirizine HCl = 12-24 hrs (schedule 1 at 20 mg strength)
  • Loratidine = 24 hrs
  • Desloratidine = 24 hrs
  • Fexofenadine = 12-24 hrs
  • Bilastine = 26 hrs (schedule 1)
  • Rupatadine = 24 hrs (schedule 1)
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10
Q

AR - Antihistamines - 2nd gen

List the side effects from 2nd gen

A

• Usually well tolerated
• Less sedation, cognitive and performance impairment
compared to 1 st gen:
- Cetirizine can cause mild sedation and somnolence
in 10% of the population, especially in higher doses
• Headache, nausea, xerostomia, pharyngitis,
dyspepsia

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11
Q

AR - Antihistamines - 2nd gen

List the drug interactions from 2nd gen

A

• CNS depressants
• Drugs with anticholinergic side-effects
• Fexofenadine:
- Antacids (aluminum and magnesium containing)
- Fruit juices (apple, grapefruit, orange) may decrease
bioavailability
• Loratidine, desloratidine:
- PgP inhibitors may increase levels (erythromycin, ketoconazole)
- PgP inducers may decrease levels (carbamazapine)
- QTc prolongation with amiodarone (loratadine)

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12
Q

AR - Antihistamines - 2nd gen

What are the 2 new Rx drugs?

A

Bilastine

Rupatadine

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13
Q

AR - Antihistamines - 2nd gen

New Rx drugs - Bilastine info:

A
  • H 1 receptor antagonist
  • Indicated for ages 12 and over
  • Available as 20 mg tab daily
  • Taken on empty stomach
  • Grapefruit juice can decrease bioavailability
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14
Q

AR - Antihistamines - 2nd gen

New Rx drugs - Rupatadine info:

A

• H 1 receptor antagonist
• Indicated for ages 2 and over
• Available as 10 mg tab and 1mg/ml solution daily
• Grapefruit juice can decrease metabolism
• Caution
- QTc prolongation
- Don’t use with CYP 3A4 inhibitors

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15
Q

AR - Intranasal Corticosteroids

1 st line therapy for ___ to ___ allergic rhinitis

A

moderate to severe

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16
Q

AR - Intranasal Corticosteroids

It’s more effective therapy than:

A

antihistamines, decongestants, and cromoglicate for allergic rhinitis
symptoms

17
Q

AR - Intranasal Corticosteroids

How does it show effectiveness?

A

• Can be used prn but more effective with continuous use
• Some benefit seen in the 1 st day of therapy (after 6-8 hrs) but max effect may take 2-4 weeks
• Effective for nasal congestion, sneezing, rhinorrhea, and pruritus
• Modest effect on ocular symptoms (effect increases with long-term use)
- Mometasone furoate and fluticasone furoate are most effective for ocular symptoms

18
Q

AR - Intranasal Corticosteroids

What cause it to fail?

A

If excessive nasal mucus secretions, may fail to reach site of action (clear secretions with
saline irrigation and then use the spray)

19
Q

AR - Intranasal Corticosteroids

What are the Mechanism of Actions?

A

• Inhibit allergic inflammation at the nose at many levels

• Down-regulate inflammatory responses by binding to intracellular glucocorticoids receptors in inflammatory cells, causing the production of anti-inflammatory
proteins and suppressing cytokines and chemokines that promote inflammation

20
Q

AR - Intranasal Corticosteroids

List the side effects

A
  • Burning, stinging, or nose bleeds
  • Case reports of nasal septal perforation (aim away from septum)
  • Rare infections with Candida albicans
  • Quickly metabolized once absorbed so adrenal suppression not seen at therapeutic doses
  • Beclomethasone (high dose) can cause growth suppression (0.9cm after 1 year of continuous use)
21
Q

AR - Intranasal Corticosteroids

List the Drugs/Sprays

A
  • fluticasone propionate 50mcg (Flonase®) - Schedule I and II
  • triamcinolone 55mcg (Nasocort®) - Schedule I and II
  • beclomethasone 50mcg (Beclonase®)
  • budesonide 64 or 100mcg (Rhinocort® Aqua or
    Turbuhaler)
  • ciclesonide 50mcg (Omnaris®)
  • fluticasone furoate 27.5mcg
  • mometasone 50mcg (Nasonex®)
22
Q

AR - Decongestants

See slide re: Allergic Cascade

A
  • some mediators cause vasodilation of nose
  • results in decreased ability to breathe
  • decongestants decrease blood vessel size/vasoconstriction in nasal cavity via alpha1 agonist activity
23
Q

AR - Decongestants

Describe the Oral Decongestants

A
  • Only work for nasal congestion, no other AR symptoms
  • Affect smooth muscle around the blood vessels throughout the body (vasoconstriction throughout!)
  • Pseudoephedrine acts on beta 1 receptors in the heart (not ideal for patients with heart disease)
  • Combination products with antihistamine available
24
Q

AR - Decongestants

Describe the Oral Decongestants

A

• Only work for nasal congestion, no other AR
symptoms
• Affect smooth muscle around the blood vessels
throughout the body (vasoconstriction throughout!)
• Pseudoephedrine acts on beta 1 receptors in the heart
(not ideal for patients with heart disease)
• Combination products with antihistamine available

25
Q

AR - Oral Decongestants

What are the side effects?

A

• Increased blood pressure and heart rate
• BP increase generally not seen in normotensive
patients unless high doses
• Insomnia, CNS stimulation, tremor, irritability,
headache
• Urinary retention

26
Q

AR - Oral Decongestants

What are the precautions?

A
  • Diabetes (can increase blood glucose)
  • Hypertension
  • BPH
  • Hyperthyroidism
  • Chronic heart failure
  • Angle closure glaucoma
  • Coronary artery disease
  • Contraindications: uncontrolled hypertension
27
Q

AR - Oral Decongestants

What are the drug interactions?

A
  • Beta blockers – reduced effect
  • MAOIs – hypertensive crisis
  • Avoid use with phenothiazines
28
Q

AR - Topical Decongestants

What are the side effects?

A

• Limited side-effect profile due to local effect
• Rhinitis medicamentosa (rebound vasodilation)
• Can occur if topical decongestants are used for more
than 3-5 days
• More likely to occur with the shorter acting agents

29
Q

AR - Mast Cell Stabilizers (Sodium cromoglycate)

What does it do to help AR?

A

Prevent antigen-triggered mast cell degranulation and release of mediators
• Onset of action is 4-7 days (better to initiate before onset of symptoms)
• Max effect may take 2-4 weeks (can bridge with antihistamines or decongestants)
• Modestly reduces itching, sneezing, and rhinorrhea but not effective for nasal congestion
• Less effective than intranasal corticosteroids
• Requires QID dosing (will adherence be an issue?)
• Side effects: burning, irritation, sneezing
• Intranasal formulation not currently available in Canada

30
Q

AR - Other Rx Options

List other Rx options

A
  • Leukotriene Receptor Antagonists (LTRAs) - 3rd line after antihitamines and intranasal corticosteroids
  • Immunotherapy (“allergy shots” - SC or SL) - for moderate-severe symptoms
  • Ipratropium - Anticholinergic spray
31
Q

AR - Other Rx Options (Combination Products)

■ Sinutab Sinus and Allergy®
■ Reactine Complete Sinus and Allergy®
■ Claritin-D for Allergy and Congestion®
What are the examples of?

A

Antihistamine + Decongestants (oral)

32
Q

AR - Other Rx Options (Combination Products)

■ Naphcon-A®, Visine Red Eye®
■ pheniramine / naphzoline
What are the examples of?

A

Antihistamines + Decongestants (ophthalmic)

33
Q

AR - Treatment Comparison (RxTx)

***See table
see special pops

A

Pregnancy

  • intranasal corticosteorids safe (beclo, bude, flut)
  • 1st gen antihistamines more data
  • montelukast safe
  • avoid oral decongestants in 1st trimester (topical ok)
  • no immunotherapy

Lactation

  • 1st/2nd gen antihis ok
  • intranasal corticoseroids, topical decongestants safe
  • pseudoephedrine considered compatible

Ped

  • 1st line = avoid allergen and intranasal saline drops
  • oral antihis (prefer 2nd gen if > 6 months)
  • intranasal cort (>2 years)
  • beclomethasone growth suppression (height recovers after treatment stops)
  • decongestants not for 6 and under
34
Q

AR - Treatment Approach

What to use for mild intermittent AR?

A

■ Second generation antihistamines → taken prn or daily

■ Alternatively: intranasal antihistamines

35
Q

AR - Treatment Approach

What to use for moderate-severe intermittent AR

A

■ Intranasal corticosteroids → used prn or daily

■ Combination therapy with intranasal antihistamine if not effective

36
Q

AR - Treatment Approach

What to use for mild persistent AR?

A

Regularly administered intranasal corticosteroids

37
Q

AR - Treatment Approach

What to use for moderate-severe persistent AR

A

■ Regularly administered intranasal corticosteroids

■ Combination therapy with intranasal antihistamine if not effective

38
Q

AR - When to refer to an allergist/immunologist

A
  • inad control of symptoms
  • AE to meds
  • reduced quality of life
  • desire to identify allergens
  • w/ asthma, sinusitis
  • assessment for immunotherapy