PC707 Module Respiratory with correct
answers 2025
WhatvarevH1RAsv-vcorrect-answersv--
H1vreceptorvisvthevmainvreceptorvthatvinvolvesvcreatingvsymptomsvduringvallergicvreactions.v
-
H1vreceptorsvarevobservedvinvthevperipheryvofvthevbody,vespeciallyvinvthevsmoothvmuscles.vApartvf
romvthevperiphery,vH1vreceptorsvresidevinvthevadrenalvmedulla,vvascularvendothelium,vheart,vandv
centralvnervousvsystem.v
-
ThevfunctionsvmediatedvbyvH1vreceptorvbindingsvarevavcontractionvofvsmoothvmuscles,vanvincreas
evinvcapillaryvpermeability,vmediatingvneurotransmissionvinvthevcentralvnervousvsystem,vamongvot
hervnecessaryvfunctions.v
-H1vreceptorsvarevusedvtovtreatvmildvallergicvdisorders.
WhatvarevH2RAsv-vcorrect-answersv--
H2vreceptorvisvanothervhistaminevbindingvreceptor.vThevwidevdistributionvofvH2vreceptorsvcanvbevs
eenvinvthevcentralvnervousvsystemvespeciallyvinvthevbrain.v
-
Receptorvconcentrationvisvhighvinvthevbasalvganglia,vhippocampus,vamygdala,vandvcerebralvcortex.v
,H2vreceptorsvarevalsovpresentvinvthevparietalvcellsvlocatedvinvthevstomach.vTheyvarevresponsiblevfor
vregulatingvthevgastricvacidvlevel.vH2vreceptorsvcanvbevseenvinvthevheart,vuterus,vandvvascularvsmoo
thvmusclevcells.v
-
ThevbindingvofvhistaminevblockersvtovH2vreceptorsvcanvreducevthevamountvofvacidvproducedvbyvth
evstomach.vHence,vH2vreceptorvblockersvarevusedvtovtreatvduodenalvulcers,vgastricvulcers,vandvZolli
ngerv-Ellisonvdiseasev(amongvothervgastric-acidvmediatedvconditions).
Whichvhistaminevreceptorvantagonistvhasvgenerations?v-vcorrect-answersv--
ThevH1vreceptorvantagonistsvarevbrokenvdownvtov1stvgenerationvantihistaminesvandv2ndvgeneratio
nvantihistamines.v
-
Antihistaminesvwillvnotvtreatvthevcausevofvrhinorrheavandvsneezingvwithvavcold,vasvsymptomsvarevn
otvrelatedvtovanvallergen.vInvfact,vit'svtheirvsecondaryveffectv(thevanticholinergicvsideveffectvofvantihi
stamines)vthatvmayvprovidevreliefvbyvdryingvthevmucousvmembranesvandvnasalvsecretions.v
-1stvgenerationsvarevHIGHLYvsedativevcomparedvtov2ndvgeneration.
1stvgenerationvH-1vantagonistvantihistamines:v-vcorrect-answersv-
relativelyvquickvonsetvofvactionvofvaboutv15vminutesvtov30vminutes.vWithvregularvuse,vtolerancevorv
drugvfailurevoccursvaftervseveralvweeksvtovmonths.vThisvisvbecausevantihistaminesvcanvinducevthevp
roductionvofvhepaticvenzymesvthatvactuallyvbreakvthemvdownv(theyvhelpvwithvtheirvownvdestructi
on).
-Thevoldervorv1stvgenerationvcrossesvthevblood-
brainvbarrier,vhencevthevsedativeveffects.vAsvthesevdrugsvblockvthevhistaminevreceptorsv(remembe
r,vtheyvarevlocatedvinvthevcentralvnervousvsystem),vtheyvalsovendvupvslowingvdownvneuronalvfiringv
andvthevproductionvofvneurotransmitters,vresultingvinvsedativeveffects.vThevsedationvcanvleadvtovi
mpairedvlearningvandvmemory;vusevsparinglyvifvatvall.
2ndvgenerationvH-1vantagonistsvantihistamines:v-vcorrect-answersv-
actvperipherally,vsovthesevH1vreceptorvblockersvarevlessvsedating.vWhyvdon'tvthev2ndvgenerationva
ntihistaminesvexertvsedativeveffects?vThesevdrugsvarevlargevmolecules,vhavevlowvlipidvsolubility,van
dvcan'tvcrossvthevblood-
,brainvbarrier.vTheyvhavevavlowvaffinityvforvthevhistaminevreceptorsvinvthevbrain.vIfvtheyvdovcrossvthev
blood-brainvbarrier,vitvisvinvnegligiblevamounts.v
**Thevonlyvexceptionvisvcetirizine/Zyrtec,vasvit'svthevonev2ndvgenerationvwithvavlongvhalf-
lifevandvsedativeveffects.v
-
Bevcautiousvrecommendingvinvthosevforvwhomvsedationvcouldvimpairvtheirvfunctioningv(e.g.,vpilots
).v
-Asvavclass,vthevonsetvisvaboutv1-2.5vhours.vTovreachvavsteady-statevitvtakesv1-
3vdays,vbutvfoodvcanvimpairvtheirvabsorption.v
-Thev2ndvgenerationvH1vreceptorvantagonistsvarevgenerally,vwell-
tolerated,vbutvavheadache,vdryvmouth,vdyspepsia,vnausea,vandvfatiguevmayvoccur.v
-
Fexofenadinev(Allegra)vmayvinteractvwithvantifungals,vcausingvconcentrationsvofvthisvantihistamin
evtovbecomevincreased.v***Fexofenadinev(Allegra)vcanvalsovprolongvQTvintervalsvifvcombinedvwithv
othervdrugsvthatvprolongvthevQTvinterval.
Whatvarevanticholinergicvsideveffectsvwithvantihistaminesv-vcorrect-answersv-
·antihistaminesvhavevlowvreceptorvspecificityvandvinteractvwithvbothvperipheralvandvcentralvhistam
inevreceptorsvandvreadilyvcrossvthevblood-
brainvbarrier.vThisvleadsvtovsignificantvcentralvnervousvsystemvsideveffects,vincludingvsedation,vdro
wsiness,vsomnolence,vfatigue,vcognitivevdecline,vpsychomotorveffects,vandvlossvofvcoordination.vT
hesevantihistaminesvarevpotentvmuscarinicvreceptorvantagonistsvtoo.vThisvcanvleadvtovseriousvantic
holinergicvsideveffects,vsuchvasvsinusvtachycardia,vdryvskin,vdryvmucousvmembranes,vdilatedvpupils,
vconstipation,vileus,vurinaryvretention,vandvagitatedvdelirium.vThevmnemonicv"blindvasvavbat,vdryva
svavbone,vredvasvavbeet,vmadvasvavhatter,vandvhotvasvavhare"voftenvisvusedvtovhelpvdescribevandviden
tifyvpatientsvsufferingvfromvanticholinergicveffects.
Whovshouldvavoidvdrugsvwithvanticholinergicvsideveffects?v-vcorrect-answersv--H-
1vreceptorvantagonist-v1stvgenerationvantihistamines:vUsevcautionvinvnarrow-
anglevglaucomav:vantihistaminesvcanvincreasevintraocularvpressure.vThesevmedicationsvhavevthevp
otentialvtovnarrowvthevdrainagevanglevofvtheveye,vpreventingveyevfluidvfromvexitingvproperlyvresulti
ngvinvhighveyevpressure.vAlso,vbevcautiousvinvpatientsvwithvbenignvprostaticvhypertrophy/hyperpla
siav,vasvantihistaminesvcanvalsovdecreasevurinevflow.vThevelderlyvarevparticularlyvsusceptiblevtovanti
cholinergicveffects.v
, -Thevoldervorv1stvgenerationvcrossesvthevblood-
brainvbarrier,vhencevthevsedativeveffects.vAsvthesevdrugsvblockvthevhistaminevreceptorsv(remembe
r,vtheyvarevlocatedvinvthevcentralvnervousvsystem),vtheyvalsovendvupvslowingvdownvneuronalvfiringv
andvthevproductionvofvneurotransmitters,vresultingvinvsedativeveffects.vThevsedationvcanvleadvtovi
mpairedvlearningvandvmemory;vusevsparinglyvifvatvall.
Whichvdrugsvinvthisvunitvhavevanticholinergicvsideveffects?v-vcorrect-answersv-·vH-
1vreceptorvantagonist-
1stvgenerationvantihistamines:vMOSTvanticholinergicv(Benadryl,vPhenergan,vVistaril)
·vH-1vreceptorvantagonist-
2ndvgenerationvantihistamines:vLEASTvanticholinergicv(Zyrtex,vAllegra,vClaritin)
Whatvisvthevrecommendationvonvcoughvandvcoldvmedicinevinvregardvtovcombinationvproducts?vW
hy?v-vcorrect-answersv-
·vThesevarevoftenvcombinationvproducts,vtypicallyvwithvacetaminophenvorvibuprofen,vavdecongest
ant,vanvantihistamine,vavcoughvsuppressantvand/orvavcoughvexpectorant.vTheyvcanvalsovcontainvalc
ohol.
·vCautionvpatientsvandvprovidevthevnecessaryveducation.vThisvwouldvincludevthevrisksvofvtoovmuchv
acetaminophenv(Tylenol)vonvthevliver,voralvdecongestantsvandvhypertension,vantihistaminesvandvs
edation,vandvpossiblyvalcoholvandvitsvriskvofvcausingvsedationvand/orvcognitivevconcerns.
·vBevsurevtovcheckvlabelsvandveducatevyourvpatientsvtovcheckvlabelsvtovmakevsurevtheyvarevgettingvo
nlyvwhatvproductvtheyvneed.
·vProvideveducationvonvthevsafetyvconcernsvwithvdrivingvorvoperatingvheavyvmachinery.
·vParentsvwithvyoungvchildrenvshouldvbevadvisedvtovusevonlyvsinglevrathervthanvcombinationvprodu
cts.vThisvisvtruevforvpregnancyvandvlactationvasvwell.vThevrationalevforvthisvisvfour-
fold:vchoosingvsinglevagentvproductsvhelpsvtovlessenvthevriskvofvoverdosing,veachvingredientvcanvbe
vdosedvseparatelyvbasedvonvagevandvweight,vitvavoidsvgivingvavmedicationvthatvisvunnecessary,vandv
ifvavreactionvtovmedicationvwerevtovoccur,vit'dvbevmuchveasiervtovdeterminevthevoffendingvagent.
·vRecentvstudiesvhavevdemonstratedvthatvcoughvandvcoldvmedicinesv(CCMs)varevoftenvunsafevinvth
evpediatricvpopulation.vManyvhavevbeenvremovedvfromvthevmarket.vCheckvthevlabeling.vItvisvrecom
mendedvbyvthevFDAvthatvOTCvproductsvnotvbevusedvinvthosevundervthevagevofv2.
answers 2025
WhatvarevH1RAsv-vcorrect-answersv--
H1vreceptorvisvthevmainvreceptorvthatvinvolvesvcreatingvsymptomsvduringvallergicvreactions.v
-
H1vreceptorsvarevobservedvinvthevperipheryvofvthevbody,vespeciallyvinvthevsmoothvmuscles.vApartvf
romvthevperiphery,vH1vreceptorsvresidevinvthevadrenalvmedulla,vvascularvendothelium,vheart,vandv
centralvnervousvsystem.v
-
ThevfunctionsvmediatedvbyvH1vreceptorvbindingsvarevavcontractionvofvsmoothvmuscles,vanvincreas
evinvcapillaryvpermeability,vmediatingvneurotransmissionvinvthevcentralvnervousvsystem,vamongvot
hervnecessaryvfunctions.v
-H1vreceptorsvarevusedvtovtreatvmildvallergicvdisorders.
WhatvarevH2RAsv-vcorrect-answersv--
H2vreceptorvisvanothervhistaminevbindingvreceptor.vThevwidevdistributionvofvH2vreceptorsvcanvbevs
eenvinvthevcentralvnervousvsystemvespeciallyvinvthevbrain.v
-
Receptorvconcentrationvisvhighvinvthevbasalvganglia,vhippocampus,vamygdala,vandvcerebralvcortex.v
,H2vreceptorsvarevalsovpresentvinvthevparietalvcellsvlocatedvinvthevstomach.vTheyvarevresponsiblevfor
vregulatingvthevgastricvacidvlevel.vH2vreceptorsvcanvbevseenvinvthevheart,vuterus,vandvvascularvsmoo
thvmusclevcells.v
-
ThevbindingvofvhistaminevblockersvtovH2vreceptorsvcanvreducevthevamountvofvacidvproducedvbyvth
evstomach.vHence,vH2vreceptorvblockersvarevusedvtovtreatvduodenalvulcers,vgastricvulcers,vandvZolli
ngerv-Ellisonvdiseasev(amongvothervgastric-acidvmediatedvconditions).
Whichvhistaminevreceptorvantagonistvhasvgenerations?v-vcorrect-answersv--
ThevH1vreceptorvantagonistsvarevbrokenvdownvtov1stvgenerationvantihistaminesvandv2ndvgeneratio
nvantihistamines.v
-
Antihistaminesvwillvnotvtreatvthevcausevofvrhinorrheavandvsneezingvwithvavcold,vasvsymptomsvarevn
otvrelatedvtovanvallergen.vInvfact,vit'svtheirvsecondaryveffectv(thevanticholinergicvsideveffectvofvantihi
stamines)vthatvmayvprovidevreliefvbyvdryingvthevmucousvmembranesvandvnasalvsecretions.v
-1stvgenerationsvarevHIGHLYvsedativevcomparedvtov2ndvgeneration.
1stvgenerationvH-1vantagonistvantihistamines:v-vcorrect-answersv-
relativelyvquickvonsetvofvactionvofvaboutv15vminutesvtov30vminutes.vWithvregularvuse,vtolerancevorv
drugvfailurevoccursvaftervseveralvweeksvtovmonths.vThisvisvbecausevantihistaminesvcanvinducevthevp
roductionvofvhepaticvenzymesvthatvactuallyvbreakvthemvdownv(theyvhelpvwithvtheirvownvdestructi
on).
-Thevoldervorv1stvgenerationvcrossesvthevblood-
brainvbarrier,vhencevthevsedativeveffects.vAsvthesevdrugsvblockvthevhistaminevreceptorsv(remembe
r,vtheyvarevlocatedvinvthevcentralvnervousvsystem),vtheyvalsovendvupvslowingvdownvneuronalvfiringv
andvthevproductionvofvneurotransmitters,vresultingvinvsedativeveffects.vThevsedationvcanvleadvtovi
mpairedvlearningvandvmemory;vusevsparinglyvifvatvall.
2ndvgenerationvH-1vantagonistsvantihistamines:v-vcorrect-answersv-
actvperipherally,vsovthesevH1vreceptorvblockersvarevlessvsedating.vWhyvdon'tvthev2ndvgenerationva
ntihistaminesvexertvsedativeveffects?vThesevdrugsvarevlargevmolecules,vhavevlowvlipidvsolubility,van
dvcan'tvcrossvthevblood-
,brainvbarrier.vTheyvhavevavlowvaffinityvforvthevhistaminevreceptorsvinvthevbrain.vIfvtheyvdovcrossvthev
blood-brainvbarrier,vitvisvinvnegligiblevamounts.v
**Thevonlyvexceptionvisvcetirizine/Zyrtec,vasvit'svthevonev2ndvgenerationvwithvavlongvhalf-
lifevandvsedativeveffects.v
-
Bevcautiousvrecommendingvinvthosevforvwhomvsedationvcouldvimpairvtheirvfunctioningv(e.g.,vpilots
).v
-Asvavclass,vthevonsetvisvaboutv1-2.5vhours.vTovreachvavsteady-statevitvtakesv1-
3vdays,vbutvfoodvcanvimpairvtheirvabsorption.v
-Thev2ndvgenerationvH1vreceptorvantagonistsvarevgenerally,vwell-
tolerated,vbutvavheadache,vdryvmouth,vdyspepsia,vnausea,vandvfatiguevmayvoccur.v
-
Fexofenadinev(Allegra)vmayvinteractvwithvantifungals,vcausingvconcentrationsvofvthisvantihistamin
evtovbecomevincreased.v***Fexofenadinev(Allegra)vcanvalsovprolongvQTvintervalsvifvcombinedvwithv
othervdrugsvthatvprolongvthevQTvinterval.
Whatvarevanticholinergicvsideveffectsvwithvantihistaminesv-vcorrect-answersv-
·antihistaminesvhavevlowvreceptorvspecificityvandvinteractvwithvbothvperipheralvandvcentralvhistam
inevreceptorsvandvreadilyvcrossvthevblood-
brainvbarrier.vThisvleadsvtovsignificantvcentralvnervousvsystemvsideveffects,vincludingvsedation,vdro
wsiness,vsomnolence,vfatigue,vcognitivevdecline,vpsychomotorveffects,vandvlossvofvcoordination.vT
hesevantihistaminesvarevpotentvmuscarinicvreceptorvantagonistsvtoo.vThisvcanvleadvtovseriousvantic
holinergicvsideveffects,vsuchvasvsinusvtachycardia,vdryvskin,vdryvmucousvmembranes,vdilatedvpupils,
vconstipation,vileus,vurinaryvretention,vandvagitatedvdelirium.vThevmnemonicv"blindvasvavbat,vdryva
svavbone,vredvasvavbeet,vmadvasvavhatter,vandvhotvasvavhare"voftenvisvusedvtovhelpvdescribevandviden
tifyvpatientsvsufferingvfromvanticholinergicveffects.
Whovshouldvavoidvdrugsvwithvanticholinergicvsideveffects?v-vcorrect-answersv--H-
1vreceptorvantagonist-v1stvgenerationvantihistamines:vUsevcautionvinvnarrow-
anglevglaucomav:vantihistaminesvcanvincreasevintraocularvpressure.vThesevmedicationsvhavevthevp
otentialvtovnarrowvthevdrainagevanglevofvtheveye,vpreventingveyevfluidvfromvexitingvproperlyvresulti
ngvinvhighveyevpressure.vAlso,vbevcautiousvinvpatientsvwithvbenignvprostaticvhypertrophy/hyperpla
siav,vasvantihistaminesvcanvalsovdecreasevurinevflow.vThevelderlyvarevparticularlyvsusceptiblevtovanti
cholinergicveffects.v
, -Thevoldervorv1stvgenerationvcrossesvthevblood-
brainvbarrier,vhencevthevsedativeveffects.vAsvthesevdrugsvblockvthevhistaminevreceptorsv(remembe
r,vtheyvarevlocatedvinvthevcentralvnervousvsystem),vtheyvalsovendvupvslowingvdownvneuronalvfiringv
andvthevproductionvofvneurotransmitters,vresultingvinvsedativeveffects.vThevsedationvcanvleadvtovi
mpairedvlearningvandvmemory;vusevsparinglyvifvatvall.
Whichvdrugsvinvthisvunitvhavevanticholinergicvsideveffects?v-vcorrect-answersv-·vH-
1vreceptorvantagonist-
1stvgenerationvantihistamines:vMOSTvanticholinergicv(Benadryl,vPhenergan,vVistaril)
·vH-1vreceptorvantagonist-
2ndvgenerationvantihistamines:vLEASTvanticholinergicv(Zyrtex,vAllegra,vClaritin)
Whatvisvthevrecommendationvonvcoughvandvcoldvmedicinevinvregardvtovcombinationvproducts?vW
hy?v-vcorrect-answersv-
·vThesevarevoftenvcombinationvproducts,vtypicallyvwithvacetaminophenvorvibuprofen,vavdecongest
ant,vanvantihistamine,vavcoughvsuppressantvand/orvavcoughvexpectorant.vTheyvcanvalsovcontainvalc
ohol.
·vCautionvpatientsvandvprovidevthevnecessaryveducation.vThisvwouldvincludevthevrisksvofvtoovmuchv
acetaminophenv(Tylenol)vonvthevliver,voralvdecongestantsvandvhypertension,vantihistaminesvandvs
edation,vandvpossiblyvalcoholvandvitsvriskvofvcausingvsedationvand/orvcognitivevconcerns.
·vBevsurevtovcheckvlabelsvandveducatevyourvpatientsvtovcheckvlabelsvtovmakevsurevtheyvarevgettingvo
nlyvwhatvproductvtheyvneed.
·vProvideveducationvonvthevsafetyvconcernsvwithvdrivingvorvoperatingvheavyvmachinery.
·vParentsvwithvyoungvchildrenvshouldvbevadvisedvtovusevonlyvsinglevrathervthanvcombinationvprodu
cts.vThisvisvtruevforvpregnancyvandvlactationvasvwell.vThevrationalevforvthisvisvfour-
fold:vchoosingvsinglevagentvproductsvhelpsvtovlessenvthevriskvofvoverdosing,veachvingredientvcanvbe
vdosedvseparatelyvbasedvonvagevandvweight,vitvavoidsvgivingvavmedicationvthatvisvunnecessary,vandv
ifvavreactionvtovmedicationvwerevtovoccur,vit'dvbevmuchveasiervtovdeterminevthevoffendingvagent.
·vRecentvstudiesvhavevdemonstratedvthatvcoughvandvcoldvmedicinesv(CCMs)varevoftenvunsafevinvth
evpediatricvpopulation.vManyvhavevbeenvremovedvfromvthevmarket.vCheckvthevlabeling.vItvisvrecom
mendedvbyvthevFDAvthatvOTCvproductsvnotvbevusedvinvthosevundervthevagevofv2.
