Pharm Respiratory part 1 (respiratory tract infections and allergic reactions)

Decongestants examples

oral: pseudoephedrine (Sudafed) and phenylephrine (Sudafed PE)

topical/intranasal: Oxymetazoline hydrochloride (Afrin) and Phenylephrine hydrochloride (Afrin Children’s, Little Remedies, Neo-Synephrine)

Which decongestants can cause rebound congestion?

Topical/Intranasal. Use should be limited to 3-4 days

Decongestants mechanism of action

stimulates alpha and beta-adrenergic receptors, causing vasoconstriction of histamine-dilated blood vessels of the respiratory tract mucosa (including nasal passageways), which reduces swelling and inflammation

Decongestant contraindications

-do not in pts who have taken MAOIs within 14 days (risk for hypertensive crisis)

-do not use in patients with severe uncontrolled hypertension and coronary artery disease

-do not use in patients with narrow-angle glaucoma (can dilate the pupils)

-caution with renal impairment, hyperthyroidism, prostatic hypertrophy, urinary incontinence

Decongestant adverse events

-increased BP/HR

-headaches, dizziness

-GI upset

-tremor, insomnia, irritability, agitation (CNS stimulant)

Expectorants examples

Guaifenesin (Antitussin, Mucinex, Robitussin)

Expectorants mechanism of action

•Increase the output of respiratory tract fluid by decreasing the adhesiveness and surface tension of the respiratory tract, facilitate the removal of thick mucous

Expectorants adverse events

drowsiness, headache, dizziness, GI upset

Antitussives examples

dextromethorphan (Delsym)

benzonatate (Tessalon Perles) 

Antitussives mechanism of action

diminish cough reflex by direct inhibition of cough center in the medulla

dextromethorphan also inhibits serotonin reuptake

Antitussives contraindications

Patients who have taken MAOIs within 14 days (antitussives have MAOI properties, so they can increase serotonin levels)

Do not use with amiodarone, MAOIs, quinidine, (agents that can inc serotonin)

Antitussives adverse events

dizziness, nausea, drowsiness

Antiinflammatories and analgesics for respiratory infections examples

naproxen (Naprosyn, Aleve)

Antiinflammatories and analgesics mechanism of action

Inhibit prostaglandin secretions to reduce headache, malaise, myalgias, cough, and even sneezing

Antiinflammatories and analgesics contraindications

-peptic ulcer/GI bleed

-severe hepaticimpairment (can alter the drugs metabolism and lead to toxic levels

-severe renal impairment and heart failure (synthesis of prostaglandins are important for maintaining kidney blood flow and function, so use can worsen heart failure)

-hyperkalemia (renin-angiotensin-aldosterone system is impaired, so potassium excretion is decreased)

-3rd trimester/breastfeeding pts

-do not use in children d/t risk of reye’s syndrome

Antiinflammatories and analgesics adverse events

Dizziness, drowsiness, headache, edema, abdominal pain, constipation, nausea, and heartburn

antiinflammatories and analgesics interactions

may increase effects of antiplatelets and anticoagulants

Anticholinergics examples

ipratropium bromide (Atrovent) nasal spray

Anticholinergic mechanism of action

•Antagonizes the action of acetylcholine at the cholinergic receptor, inhibits secretions from the serous and seromucous glands lining the nasal mucosa

•The result is a decrease in nasal discharge and rhinorrhea (runny nose)

Anticholinergic contraindications

-pts with narrow-angle glaucoma (can dilate the pupils, blocking drainage and increasing intraocular pressure)

-pts with prostatic hyperplasia or bladder neck obstruction (can cause increased urinary retention)

anticholinergic adverse events

headache

nasal dryness and bleeding, pharyngitis (inflammation in back of throat) (these meds can decrease saliva production, leading to dryness)

antihistamine 1st generation (sedating) examples

diphenhydramine (Benadryl)

chlorpheniramine (Chlor-Trimeton)

brompheniramine (Dimetapp)

anithistamine 2nd generation (non-sedating) examples

cetirizine (Zyrtec)

loratadine (Claritin)

desloratadine (Clarinex)

fexofenadine (Allegra)

Use of antihistamines in the common cold

1st gen may be effective when combined with decongestants for symptoms of runny nose and fullness in the ears

Antihistamine-induced dryness may exacerbate symptoms of congestion and cause upper airway obstruction by impairing the flow of mucus

antihistamine mechanism of action

compete with histamine released from mast cells and basophils in the nasal passageways to bind to H1 receptors

1^st generation agents antagonize acetylcholine at muscarinic receptors

antihistamine contraindications

caution in older pts d/t inc risk for confusion, constipation, and dizziness

diphenhydramine: avoid in pts who are breastfeeding (also neonates). Caution in pts with asthma (anticholinergic thickens and dries secretions), CVD, inc intraocular pressure, prostatic hyperplasia, bladder neck obstruction, thyroid dysfunction

chlorpheniramine: do not use in pts with narrow-angle glaucoma, bladder neck obstruction, prostate hypertrophy, stenosing peptic ulcer, pyloroduodenal obstruction (anticholinergic effect slows down the digestive tract), and acute asthma attacks

antihistamines adverse events

1st gen cross the blood brain barrier, so their is a higher incidence of anticholinergic and CNS adverse events

-confusion, dizziness, drowsiness, tachycardia, sedation, urinary retention, dry mouth, blurry vision, etc

1st gen may potentiate effects of other sedative drugs/alcohol

Which antihistamine is useful in severe hives reactions?

cetirizine (Zyrtec)

1st line antibiotics to treat rhinosinusitis

amoxicillin

augmention

can be considered for empiric treatment

2nd line antibiotics to treat rhinosinusitis

doxycycline

fluroquinolones

•Levofloxacin (Levaquin)

•Moxifloxacin (Avelox)

combo of clindamycin and 3rd gen cephalosporins in penicillin allergic children

can be considered for empiric treatment

antibiotics to avoid as empiric treatment for rhinosinusitis

macrolides (mycins)

trimethoprim-sulfamethoxazole (Bactrim)

3rd gen cephalosporins

•Cefixime (Suprax)*

•Cefpodoxime (Vantin)*

*Can be used in peds if inital tx fails

Why should certain antibiotics be avoided as empiric treatment for rhinosinusitis?

it can lead to high levels of resistance in bacteria that cause respiratory infections, such as Streptococcus pneumoniae

Antiviral example

Oseltamivir (Tamiflu)

antiviral mechanism of action

inhibits neuraminidase receptor binding, so infected host cells are unable to replicate, thus reducing the viral load and disease progression

most effective when started within 48 hours of symptom onset

antiviral adverse events

N/V, diarrhea

peds: confusion, delirium

oseltamivir interactions

probenecid (gout medication) increases oseltamivir concentration 2.5 x by lowering uric acid levels in the blood

Type 1 allergic reaction onset of symptoms

immediate, minutes to hours

Type 1 allergic reaction clinical manifestations

anaphylaxis, hives, itching, wheezing, hypotension, angioedema

Type II (cytotoxic) allergic reaction onset of symptoms

often < 72 hours, but can be up to 15 days

Type II (cytotoxic) allergic reaction clinical manifestations

autoimmune, hemolytic anemia, thrombocytopenia

Type III (Immune Complex) allergic reaction onset of symptoms

1-3 weeks

Type III (Immune Complex) allergic reaction clinical manifestations

serum sickness, fever, rash, lymphadenopathy, joint pain

Type IV (Delayed) allergic reaction symptom onset

variable (days to weeks)

Type IV (Delayed) allergic reaction clinical manifestations

rash

anaphylaxis

Type 1 hypersensitivity reaction involving Ig-E mediated release of histamine, leukotrienes, and other chemicals from already sensitized mast cells and basophils in response to an allergen

-results in angioedema, flushing, pruritis, uticaria, N/V, wheezing

anaphylactoid reaction

non Ig-E mediated, agent causes a direct release of histamine and other inflammatory toxins from mast cells and basophils without the involement of the immune system

medications to treat anaphlyactic reactions

epinephrine

antihistamine injection

albuterol

systemic corticosteroids

pharmacologic agents to treat allergic rhinitis

Nonsedating antihistamines

vCetirizine (Zyrtec), Levocetirizine (Xyzal)

vFexofenadine (Allegra) – Drug interaction risk

vLoratadine (Claritin), Desloratadine (Clarinex)

Nasal decongestants

vOxymetazoline (Afrin)

vPhenylephrine (Neo-Synephrine)

vPseudoephedrine

Intranasal Corticosteroids

vCiclesonide (Omnaris)

vFluticasone furoate (Flonase Sensimist)

vFluticasone propionate (Flonase Allergy Relief)

vMometasone (Nasonex 24HR Allergy)

Fexofenadine (Allegra) clinical pearls

risk for QT prolongation

certain juices can also affect absorption

interactions with many drugs

caution in patients with renal impairment

intransal antihistamines adverse events

bitter taste, possible sedation

intranasal corticosteroids mechanism of action

Binds to intracellular glucocorticoid receptor, to reduce inflammatory mediators, increase anti-inflammatory mediators (depending on cell target)

Intranasal corticosteroids adverse events

local irritation, bleeding, septal perforation, risk of systemic effects with long term use (less likely with fluticasone and mometasone)

Intranasal cromolyn drug name

Cromolyn sodium (NasalCrom)

intranasal cromolyn mechanism of action

•Mast cell destabilizer: Prevents antigen-induced degranulation of sensitized mast cells, which inhibits the release of histamine and other inflammatory cytokines

•Not for acute treatment (Begin 2-4 weeks prior to exposure and continue throughout)

Intranasal cromolyn contraindication

acute asthma attack

intranasal cromolyn adverse events

burning, stinging, bleeding/irritation inside of nose

increased sneezing

cough, headache, unpleasant taste

immunotherapy definition

aka desensitization, hyposensitization, or allergy shots

Repeated subq injections of increasing concentrations of the allergens responsible for the patient’s allergy symptoms

patients must have documented IgE antibodies to these allergens