OTC/Cough Pharm Flashcards
cough is produced in three consecutive processes - what are they
irritants stimulate receptors (throat, ears, esophagus, pleura, etc)
vagus sends afferent signals to medulla cough center
efferent signals go expiratory muscles (spinal motor), diaphragm (phrenic), and larynx (vagus)
5 main categories in cough DDx
airway irritants, airways disease (asthma, bronchitis, etc), parenchymal disease, CHF, drugs (ACE inhibs)
4 modes for further cough workup
imaging, PFTs, GI work up (rule out GERD), empiric tx (diagnostic tool)
brand name and drug category of guaifenesin
mucinex- expectorant
guaifenesin moa
reduces mucus viscosity (unknown for sure how)
no benefits in clinical data
N-acetylcysteine moa, brand name, category
reduces disulfide bonds to degrade mucin proteins
mucomyst
mucolytic, given by inhalation
benzonatate brand name, moa
tessalon, inhibits cough receptors in bronchioles to stop cough cascade before it begins
technically a local anesthetic, Na channel blocker
benzonatate category
peripherally acting Na blocker
not OTC!
what are the centrally acting antitussives?
dextromethorphan (robitussin) and codeine
dextromethorphan moa
glutamate antagonist, inhibits glutamate signalling of efferent pathways to cough muscles
dextromethorphan toxicities
dissociative disorders (amnesia, depersonalization, etc) along w/ potential for abuse
codeine moa
opioid receptor agonist- binds to mu receptor on both pre and post synapse in CNS
pre: inhibition of Ca influx and thus neurotransmitter (glutamate) release
post: stimulation of K+ efflux, hyperpolarization
a1 agonist decongestants
pseudoephedrine and phenylephrine (sudafed)
sudafed/ sudafed PE moa
a1 agonists- induce vasoconstriction and reduce swelling in nasal mucous membranes
moa also works for hemorrhoids
1st generation anti histamine decongestants
diphenhydramine (benadryl) and promethazine
2nd generation anti histamines
loratadine (claritin), fexofenadine (allegra), ceterizine (zyrtec)
histamine source and fn
released by mast cells during allergic response, triggered by IgE
receptors are found on many inflammatory cells
promote capillary permeability and vasodilation in the endothelium, inhibit sleep in the brain
histamine role in pathology
excess vasodilation and cap permeability causes swollen nasal mucous membranes
histamine role in the brain
inhibits sleep, promotes wakefulness
important neurotransmitter to H1, H2, H3 receptors
main diff and similarity b/w 1st and 2nd gen anti histamines
1st gen cross blood brain barrier, inhibit histaminergic neurons and cause drowsiness
2nd gen dont cross BBB
both targeting H1 receptors
3 other fns for promethazine
sedative- H1
anti emetic and anti psychotic - dopamine D2 receptor
