Meds for cough and cold Flashcards
Classes of drugs to treat runny nose/sneezing
Intranasal ipratropium (mucoregulator)
Intranasal/inhaled cromoglicic acid
H1 antihistamines
Intranasal corticosteroid
Class of drugs to treat sore throat and headache
Analgesics
Class of drugs to treat fever
Antipyretic
Class of drugs to treat blocked nose
Nasal decongestant
Class of drugs to treat dry cough
Cough suppressants/antitussive
Class of drugs to treat wet cough
Expectorants and mucoactive agents
What is a common cold?
Viral infection of URT
- cough and cold meds for symptomatic relief only
- usually resolve within 3-7 days
Pathophysio of common cold that causes nasal congestion
Viral infection -> trigger mast cell degranulation -> release histamine and inflammatory mediators -> inflammation -> vasodilation and excess mucus production -> nasal congestion/rhinorrhea
What is post-nasal drip?
When mucus drip and irritate back of throat
Associations of nasal congestion
Decreased sympathetic vasoconstriction of submucosal blood vessels
Increased parasympathetic stimulation of mucus secretion
Eg of mucoregulator
Ipratropium -> M3 antagonist
Uses of mucoregulators
Used to control sever cold symptoms
Decrease mucus hypersecretion from goblet cells and submucosal glands
MOA of ipratropium
Short acting muscarinic receptor antagonist (SAMA)
Blocks inflammation-induced parasympathetic cholinergic receptor (M3) activation of submucosal glands/goblet cells
Decrease stimulated mucus output and sputum vol
DOES NOT dry basal secretion/increase normal viscosity
Side effect of ipratropium
Few as little enters systemic circulation via intranasal route
Unpleasant taste -> non-compliance
Dry mouth
Urinary retention in elderly -> indicates that a lot of the drug is entering systemic circulation
What kind of drug is cromoglicic acid?
Mast cell stabiliser
MOA of cromoglicic acid
Controls Cl- channels to inhibit cellular activation
Decrease mast cell degranulation induced by IgE-mediated Fc epsilon RI crosslinking
Decrease secretion of inflammatory mediators from eosinophils, neutrophils and macrophages
Increase secretion of annexin A1
- annexin A1 inhibits prostaglandin and leukotriene pdtn
Side effects of cromoglicic acid
Throat and nasal irritation, mouth dryness, cough
Unpleasant/bitter taste -> non-compliance
Uses of antihistamine
Treat rhinorrhea
Eg of decongestants
Sympathomimetic agents
- phenylephrine, oxymetazoline, naphazoline, pseudoephedrine, ephedrine
Nasal glucocorticoid
- fluticasone, mometasone
NOTE: intranasal more effective than oral
MOA of sympathomimetic agents
Direct alpha adrenoceptor agonist
- alpha-1 selective: phenylephrine
- non-selective: oxymetazoline/naphazoline
Indirect increase in release of adrenaline/noradrenaline
- pseudoephedrine/ephedrine
Vasoconstriction of nasal blood vessels
Reduce inflammation and secretion of mucus
Administration of nasal glucocorticoid
Intranasal
MOA of nasal glucocorticoid
Anti-inflammatory -> decrease inflammation -> decrease congestion and mucus secretions
Notable feature of fluticasone
Rose water odour -> pt can’t tolerate -> non-compliance
Adverse effects of sympathomimetics
Rebound congestion
- occurs w/ prolonged use of topical intranasal decongestants -> compensatory upregulation of endogenous parasympathetic sys
CNS stimulation
- more likely w/ oral decongestants
- restlessness, tremors, irritability, anxiety and insomnia
CVS
- via activation of alpha adrenoceptors
- more likely oral decongestants
- hypertension due vasoconstriction
- tachycardia
Adverse effects of glucocorticoids
Systemic side effects limited by intranasal delivery
Local mucosal dryness and irritation
Proper way to deliver nasal drops and sprays
Lie down and tilt head back before applying drops/bend body forward all the way down and apply drops
- as long as body is not put in a position that can allow medication to be easily ingested (i.e: standing)
Why should you know over-the-counter cough and cold formulations?
To avoid prescribing drugs in the same class to pts
What is cough?
Defense reflex mechanism to clear upper airways
Eg of protussive stimuli
Cigarette smoke
Bradykinin
PGE2
Histamine
TNF-alpha
Management of cough
Elimination of precipitating factor and treatment of underlying cause
Pathophysio of cough
Sensory input to brainstem nuclei regulating cough generation -> antitussive and cough suppressants work in CNS to suppress cough
How are antitussives classified? Which one is more potent?
Opioid antitussives
- more potent
Nonopioid antitussives
Eg of opioid antitussives
Codeine
Pros and cons of codeine
Pros
- most effective/potent antitussive
Cons
- potential for abuse
- sedation
- respi depression on overdose
- risk in pts w/ severe respi insufficiency
Eg of nonopioid antitussives
Dextromethorphan
- most potent antitussive among nonopioid class
Diphenhydramine
- 1st gen antihistamine
Pros and cons of dextromethorphan
Pros
- less risk of addiction
- most effective non-opioid antitussive
Cons
- drowsiness, dizziness
- GIT adverse effects
- potential for abuse at high doses
Pros and cons of diphenhydramine
Pros
- no risk of addiction
Cons
- sedation
- anticholinergic adverse effects
MOA of codeine
Acts in CNS to suppress cough
Cautions to take when prescribing codeine
CYP2D6 ultra-rapid metabolisers -> more codeine rapidly converted to morphine -> greater risk of opioid adverse effect if dose is not adjusted
Children more sensitive to opioid-induced respi depression as respi centres and livers are not fully developed -> not recommended for those <18 yrs old
Uses of dextromethorphan
Non-productive cough
MOA of dextromethorphan
Acts in CNS to suppress cough
Adverse effects of dextromethorphan
CNS -> drowsiness, dizziness, confusion, insomnia, excitement, nervousness
- last 3 exp at higher doses
GIT -> nausea, vomiting, stomach pain
Abuse potential at high dose -> dissociative anaesthetic-like effect
Opiate vs opioid
Opiate
- chemical derived from components of opium
Opioid
- agonist at opioid receptor
Actions of opiate
Nonselective serotonin reuptake inhibitor
Sigma-1 receptor agonist
NMDA receptor blocker at high dose
MOA of diphenhydramine
Antihistamine
MOA of antitussive action unknown
Adverse effects of diphenhydramine
Sedative
Anticholinergic
What kind of drug is guaifenesin?
Expectorants
- promote coughing -> increased fluid in airways stimulates more coughing
Uses of guaifenesin
Wet cough
Dosage forms of guaifenesin
Oral soln
Tablet
MOA of guaifenesin
Increases pdtn of respi tract fluids to help liquefy and reduce viscosity of tenacious secretions
Adverse effects of guaifenesin
GIT disturbance
Nausea
Advise to pts when prescribing guaifenesin
Not for persistent cough associated w/ asthma/smoking
Take w/ adequate fluid to make secretions less viscous and protect renal fn
- kidney stones reported on overdose
Is guaifenesin suitable for children?
Caution <6 yrs old
Not indicated < 2 yrs old
Eg of mucolytics and their dosage forms
Acetylcysteine, carbocisteine
Inhalation, effervescent tablets, oral granules, syrups
Disadvantage of mucolytic agents
Smells and tastes strongly of sulphur -> non-compliance
MOA of mucolytics
Free sulfhydryl grp opens disulphide bonds in mucoproteins -> lowers mucus viscosity
Adverse effects of mucolytics
Bronchospasm -> used w/ caution for pts w/ asthma
Anaphylactoid rxns -> rash, hypotension, dyspnea, wheezing
GIT disturbance -> carbocisteine contraindicated in pts w/ active peptic ulcer
What grp of pts req caution when administering mucolytics?
Elderly/debilitated pts w/ severe respi insufficiency
Pts w/ asthma
Eg of mucokinetics
Bromhexine
Ambroxol
- active metabolite of bromhexine
MOA of mucokinetics
Promote mucus clearance
- increase ciliary beat freq
- decrease adherence of mucus to cilia
Stimulate surfactant pdtn
- surfactant is an anti-glue factor to prevent mucus from sticking to alveolar and bronchial walls
Antioxidant as free radical scavenger
Anti-inflammatory by decreasing cytokines
Suppresses influenza virus multiplication
Local anesthetic by blocking voltage-gated Na+ channel
Potential side effects of mucokinetics
Allergic rxns
Cutaneous adverse effects
Avoid in pts w/ hist of asthma and peptic ulcer disease
Caution < 6yrs old
Not indicated < 2 yrs old
Is cough and cold medication safe for paediatric use?
Usually don’t medicate, only observe closely as infection takes its normal course
- under 2 yrs usually not recommended
- 2 yrs and above use w/ caution
