chronic rhinitis, cough and cold medications Flashcards
what is an antitussive
substance that suppresses cough
what are centrally acting antitussive
dextromethophran
opiates
what are locally acting anti-tussives
benzonatate
what is the MOA for dextromethophan
crosses the BBB and activates sigma opioid receptors on the cough center in the CNS (Medulla), thereby suppressing the cough reflex
does not affect ciliary activity (in the bronchial tree)
what are the indications for dextromethorphan
short-term relief of cough
what are the interactions with dextromethophan
avoid co-use with MAOIs and in SSRI/SNRI - can cause serotonin syndrome
what are the adverse drug effects with dextromethophan
mild and infrequent dizziness and drowsiness
at very high doses (when used recreationally) can cause hallucinogenic state
serotonergic effects
what are the contraindications for dextromethorphan
avoid in chronic cough
avoid in hepatic disease
avoid when operating machinery
what is the MOA for codeine
supress cough reflex centrally (though evidence does not necessarily suppport this)
dries bronchial secretions
often co-administed with guaifensesin (expectorant)
what are the indications for codeine use
short term relief of cough
what are the interactions with codeine
conver to morphine in liver via cytochrome P450
concomitant use of opiates leads to sedation and respiratory depression
what are the adverse effects of codeine
tolerance
respiratory depression
sedation
n/v
potential for abuse
pruritus
what are the contraindications for codeine
illeus
respiratory depression
head injury
seizures
hepatic failure
what is the MOA for benzonatate
anesthetizes the stretch receptors of vagal afferent fibers in the lungs, reducing the urge to cough after deep inhalation; periphally-acting
what are the interactions with benzonatate
can be additive to other local anesthetics
what are the indications for benzonatate
mostly for relief of chronic cough, but sometimes used for acute cough (with variable success)
what are the adverse effects of benzonatate
well tolerated, GI upset, local anesthesia from chewing
overdoses - cardiac arrhythmias, seizure, bronchospasm
when are benzonatate contraindicated
avoid in allergy to ester anesthetics
what is the MOA of guaifenesin
loosens secretions to allow for more productive cough - increases volume and reduces viscosity of phlegm in trachea/bronchi
cilia can then more easily propel/mobilize secretions upward
what are the indications for guaifenesin
treatment of acute cough
what are the contraindications for guaifenesin
should not be used for chronic cough
avoid in pediatrics; can lead to seizures in this population
what are the adverse effects of guafenesin
rare at recommended doses
excessive use can result in nephrolithiasis
what are histamines
produced by mast cells and basophils
released by an immunologic trigger or following a mechanical or chemical stimulus
how many receptors do histamines have
4 different types but only two are pharmacologically important
where are H1 receptors located
smooth muscle cells. endothelium and brain
where are H2 receptors located
gastric mucosa mast cells, immune cells and brain
what are the general effects of histamine
local vasodilation
transudation of fluid through endothelial cells
stimulates nerve endings, producing pain and itching
what are organ-specific effects of histamine
lung - bronchoconstriction
GI tract: contraction of smooth muscle, potent secretagogue for gastric acid secretion, pepsin and intrinsic factor
brain - neurotransmitter
what are first generation antihistamines
diphenhydramine (Benadryl) and hydroxyzine (vistaril or atarax)
what are the second generation antihistamines
cetirizine, loratadine and fexofenadine
when should first generation antihistamines be avoided
elderly - it may cause delirium, dizziness, urinary retention
what is the use for cetirizine
crosses BBB a little, little drowsiness but better for itching, hives
what are the pharmacokinetics of first generation antihistamines
act quickQ6h
sedating
hydroxyzine can be used as an anxiolytic agent
what are the pharmacokinetics of second generation antihistamines
24 hour non-drowsy formulation
what is the MOA for pseudoephedrine
sympathomimetics, alpha and beta 2 adrenergic receptor agonist
- direct stimulation of alpha-adrenergic receptors of respiratory mucosa causes vasoconstriction and of beta-adrenergic receptors causes bronchial relaxation
reduces tissue hyperemia and edema
reduces nasal congestion and opens blocked eustachian tubes
what is pseudoephedrine indicated for
decongestant: acute nasal congestion, sinusitis, otitis media
what are the adverse effects of pseudoephedrine
increases HR and contractility
contraindicated in patients with heart disease, severe HTN or uncontrolled DM
what is the chemical precursor to the manufacture of methamphetamine
pseudoephedrine
what is the MOA for phenylephrine
binds primarily to alpha1 receptors, causing vasoconstriction
what are the indications for phenylephrine
decongestant: nasal decongestant
less effective for treatment of rhinitis symptoms than pseudoephedrine
what are the pharmacokinetics of phenylephrine
oral or intranasal
what are the AE of phenylephrine
increases systolic and diastolic pressure - induces reflex bradycardia
what are the interactions with phenylephrine
ACE inhibitors, CCBS can increase clearance, making less effective
interaction with MAOIs, TCAs can increase concentration
what are the common oral decongestatns
pseudoephedrine
phenylephrine
what is oxymetazoline
afrin - topical decongestant
appropriate for treating acute rhinitis
what are the pharmacokinetics of oxymetazoline
long acting form (~12 hours per spray)
dosed twice daily for max of 3 days
what are the AE of oxymetazoline
longer duration of use can lead to rebound congestion
what is the MOA for inhaled nasal fluticasone
glucocorticoid receptor agonist - causes vasoconstriction and inhibitory effects of cells and mediators of inflammation
what are the indication for inhaled nasal fluticasone
treatment and prevention of allergic rhinitis; treatment of chronic nasal polyps
not indicated for treatment of acute upper respiraotry infections
what are the adverse effects of inhaled nasal fluticasone
epistaxis
pharyngitis
systemic absorption of steroid is possible
what are the available inhaled antihistamines
azelastine and olopatadine - intranasal administration
what are the indications for inhaled antihistamines
indicated for allergic rhinitis in adults and children > 12
what are side effects of inhaled antihistamines
nose bleeds, headaches are possible side effect
somnolence, poor taste
