Pharm Notes Study Guide 1 - Test Prep PDF

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Summary

Textbook: Pharmacology for the Primary Care Provider, 4th ed. (2013), Edmunds & Mayhew. Mosby Elsevier....

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Foundations, Pharmacokinetics, Prescriptions, Topical Agents, Smoking Cessation: Chapter1-14, 72, [15 chapters]!

! Ch.$1$:$Prescriptive$Authority$and$Role$Implementation:$Tradition$vs.$Changes$! • • •

primary!care!à!prevention,!diagnosis,!prescription!and!treatment!!! physicians!and!dentist!are!the!professionals!who!traditionally!have!been!given!the!undisputed! right!to!prescriptive!authority!! previously!the!top!5!categories!of!prescription:!! • antidepressants!! • nonsteroidal!anti-inflammatory!agents!! • antihistamines/!bronchodilators!! • antihypertensives!! • antihyperlipidemics!! !!

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problems!in!prescribing!practice!of!physicians!(p.3)!! • problems!created!in!writing!up!to!date!prescriptions!bc!of!physician!failure!to!keep! abreast!of!changes!! • pharm!companies!influence!practice!and!provide!drug!samples!! • consumers!provide!pressure!to!prescribe!meds!! • prescriptions!are!often!illegible!!

Ch.$2$Historical$Review$of$Prescriptive$Authority! • Basics!of!prescriptive!authority! o Historically!was!the!domain!of!physicians!and!dentists! o Now:!APRN,!PA,!PharmD,!optometrist,!etc.! o Nurse!Practice!Acts!were!amended!to!include!broader!authority!to!“treat,!diagnose,!and! prescribe”! • Legal$authority! • States!control!who!may!prescribe,!dispense,!and!administer!drugs! • It!is!addressed!in!statutes,!rules,!and!regulations!that!outline!licensure!and!scope!of! practice! • History!of!prescriptive!authority! o Delegable!authority!–!requires!nurse!to!perform!under!direction!of!physician,!mandates! initial!physician-patient!relationship,!and!is!legally!based!in!medical!practice!acts! § (1)!Physician!determination!of!patient-specific!medications!and!authorization!of! the!nurse!to!prescribe!accordingly!for!the!patient! § (2)!Standing!order/protocol!that!serves!as!instructions!for!prescribing! § (3)!Renewal!of!prescriptions,!based!on!prescriptions!initially!ordered!by!MD! nd o 2 !route!to!prescriptive!authority!is!that!legislated!by!the!state!nurse!practice!act!or!by! rules!of!state!BON!! § (1)!Dependent'authority!–!MD!retains!ultimate!authority!through! countersignature!of!prescriptions!and/or!by!written!agreement!between!NP!and! MD!that!outlines!need!for!NP!chart!review,!discussion,!and!oversight!with!MD! collaborator! § (2)!Independent'authority!–!allows!NP!to!prescribe!alone! • Guidelines!utilized!by!APRNs!to!prescribe!controlled!substances! o Only!those!who!are!granted!prescriptive!authority!to!prescribe!controlled!substances!can! obtain!DEA!number! o Letter!M!precedes!DEA!number!–!alerts!pharmacists!and!wholesalers!that!midlevel! provider’s!controlled!substance!authority!may!be!subject!to!specific!state!restrictions! • Roles$of$APRNs$and$non-physician$providers,$scope$of$practice$issues! • Clinical!Nurse!Specialist!–!expert!in!clinical!practice! § Have!some!form!of!prescriptive!authority!in!30!states! § 8!of!these!states!restrict!authority!to!CNSs!in!psych/mental!health! • CRNA!–!anesthesia!specialists!who!provide!preop,!intraop,!and!postop!care!in!the!mgmt! and!resuscitation!of!critical!patients! § 16!states!have!opted!out!of!federal!physician!supervision!requirement! § An!order!to!dispense!a!drug!immediately!to!a!pt!who!s!in!bed!in!a!hospital!is! NOT!a!prescription! § CRNAs!engaged!in!traditional!practice!do!NOT!need!prescriptive!authority!or!an! individual!DEA!number,!but!if!the!state!grants!Rx!authority!to!CRNAs,!they!are! subject!to!DEA!requirements! • Certified!Nurse-Midwife!–!practice!includes!primary!care!services!including!gynecologic! and!family!planning,!preconception!care,!care!during!pregnancy,!childbirth,!postpartum,! care!of!newborn,!and!tx!of!male!partners!for!STDs!

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CNMs!granted!authority!to!write!Rx!in!all!50!states!and!D.C! Certified!midwives!only!granted!Rx!authority!in!New!York! Rx!authority!regulated!by!STATE!agencies!and!regulatory!boards!

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NPs!have!some!form!of!Rx!authority!in!all!states! As!of!2012,!NPs!have!full!independent!Rx!authority!in!19!states! In!30!states,!NPs!need!some!physician!involvement! Some!states!limit!quantity!prescribed! Freedom!to!prescribe!controlled!substances!varies!across!states!and!schedules! of!controlled!substances!

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CH.$3$:$General$Pharmacokinetic$and$Pharmacodynamics$Principles$! • • •

Drugs!have!3!names:!a!chemical,!generic!and!trade/brand!name!! Providers!should!refer!to!drugs!by!their!generic!names!when!communication!with!patients!and! other!health!care!providers!! Principles!of!pharmacokinetics:!! • Absorption$(p.$21)$! • Describes!how!the!drug!leaves!its!site!of!administration!! • Bioavailability!à!of!the!product!is!what!is!most!important!clinically!! • It!is!how!much!of!the!drug!that!is!administer!reaches!its!site!of!action!! • F!value:!the!fraction!of!the!drug!that!reaches!the!systemic!circulation!! • FACTORS!THAT!AFFECT!ABSORPTION:!!!!!!(p.!22)!! • (1)!Drug!Characteristics!! • formulation!of!the!drug!à!influences!dissolution!rate!of!solid!form!of! drug!! • concentration!of!drug!à!the!higher!the!concentration,!the!more!quickly! the!drug!is!absorbed!! • liphophilic!drug!!formulation!are!more!readily!absorbable!! • acidic!drugs!become!nonionized!in!the!acidity!of!the!stomach!and!then! diffuse!across!membranes!(*!a!change!in!the!pH!of!the!stomach!will! affect!absorption!of!many!drugs)!! • (2)!Routes!of!Administration!! • Oral!! • Most!common!! • Most!convenient!! • Safest!! • Disadvantages!include!à!(1)!Poor!GI!absorption!(2)!irritation!of! the!GI!mucosa!resulting!in!ulceration/!emesis!(3)!destruction!of! drugs!may!occur!d/t!digestive!enzymes/!low!gastric!pH!(4)! possible!drug/food!interactions!! • In!order!from!fastest!to!slowest!absorption:!! • Liquid,!elixers,!syrups,!suspensions,!solutions,!powders,! capsules,!tablets,!coated!tables,!enteric!coated!tablets,! and!slow!release!! • Controlled!release!à!provide!slow/!uniform!absorption!of!drug,! usually!from!8-12!hours!! • Sublingual!! • PRO*:!they!avoid!the!first!pass!phenomenon!(avoids!the!liver)!! • Ex:!nitro!for!chest!pain!! • Topical!! • Avoids!1st!pass!of!metabolism!via!liver!! • Lipid!soluble!drugs!may!not!be!absorbed!bc!the!skin!acts!as!a! lipid!barrier!!

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Important!to!apply!topical!meds!to!intact,!healthy!skin!to!ensure! the!correct!absorption!!

Rectal!! • Good!when!pt!is!vomiting/!unconscious!! • Advantage:!less!first!pass!metabolism!of!the!drug!through!the! liver!occurs!for!rectal!than!for!oral!meds!! • Absorption!tends!to!be!more!inconsistent!! Inhalation!! • Nasal!spray!à!for!local!topical!absorption!! • Inhaler/!neb!à!for!pulmonary!absorption!!à!uses!large!surface! area,!making!absorption!rapid!! • Also!avoids!first!pass!metabolism!in!the!liver!! Opthalmic!! • Drops!or!ointments!! • Instill!into!the!pouch!of!the!lower!eyelid!and!should!not!be! applied!directly!to!the!eye!surface!! • Anything!formulated!for!use!on!the!eye!can!be!used!anywhere! else!in!the!body!! (3)!Blood!Flow!! • circulation!!at!the!site!of!administration!is!important!in!the!drug! absorption!process!! • decreased!circulation!will!result!in!decreased!drug!absorption!! • ex:!insulin!injected!into!the!thigh!muscle!followed!by!exercise! will!produce!more!rapid!absorption!of!the!insulin!than!occurs! without!exercise.!! (4)!Cell!Membrane!Characteristics!! • when!drugs!are!absorber,!they!pass!through!cells,!not!between! them,!therefor!the!drug!must!pass!through!the!cellular!wall/! membrane!

Chapter!3:!General!Pharmacokinetic!and!Pharmacodynamics!principles! •

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Principles!of!pharmacokinetics! • Pharmacokinetics!definition:!the!study!of!the!action!of!drugs!in!the!body,!including!the! processes!of!absorption,!distribution,!metabolism,!and!elimination;!“what!the!body!does! to!the!drug”! Absorption:!how!the!drug!leaves!its!site!of!administration! • Bioavailability:!how!much!of!the!drug!that!is!administered!reaches!its!site!of!action!(this! is!considered!most!important!clinically)! • F'value:'the!fraction!of!the!drug!that!reaches!the!systemic!circulation!! • Bioequivalence:!two!drug!products!who!contain!the!same!active!ingredients,!are! identical!in!strength!or!concentration,!dosage!form,!and!route!of!administration,!and! have!essentially!the!same!rate!and!extend!of!bioavailability!! • This!can!be!an!issue!with!generic!vs!trade!drugs!

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Drug!characteristics!relevant!to!all!routes!of!administration! • Formulation!of!the!drug:!influences!dissolution!rate!of!solid!form!of!drug! • Concentration!of!the!drug:!the!higher!the!concentration,!the!more!quickly!the! drug!is!absorbed!! • Lipophilic!drug!formulations!are!more!readily!absorbable:!non-ionized!drugs!are! more!lipid!soluble!and!may!readily!diffuse!across!cell!membranes.!Ionized!drugs! are!lipid!insoluble!and!nondiffusible! • Acidic!drugs!become!nonionized!in!the!acidity!of!the!stomach,!then!diffuse! across!membranes—note!that!a!change!in!the!pH!in!the!stomach!will!affect!the! absorption!of!many!drugs! Routes!of!administration:! • Oral! • Advantages:!most!common,!most!convenient,!most!economical,!and! safest!route!of!administration.!! • Disadvantages:!Poor!GI!absorption!can!occur!because!of!physical! characteristics!of!the!dug,!oral!medication!can!cause!GI!upset,!drugs! could!be!destructed!due!to!digestive!enzymes!and!low!gastric!pH,! interactions!between!drug!and!food!can!occur! • Sublingual:!drugs!that!are!nonionic!and!have!high!lipid!solubility!are!quickly! absorbed!by!oral!mucosa! • Advantages:!these!drugs!avoid!the!first-pass!phenomenon—drug!will! reach!the!site!of!action!quickly! • Topical! • Skin!that!is!not!intact!will!absorb!more!readily;!apply!to!intact!and! healthy!skin!to!ensure!correct!absorption!! • Advantages:!topical!drugs!also!avoid!the!first-pass!metabolism!of!the! drug!through!the!liver! • Rectal! • Advantage:!less!first-pass!metabolism!of!the!drug!through!the!liver! occurs!for!rectal!meds!vs.!oral!meds! • Disadvantages:!more!inconsistent!and!less!complete!than!oral! absorption!! • Inhalation! • Advantages!for!inhaled!pulmonary!medication:!pulmonary!absorption! uses!a!large!surface!area!which!makes!absorption!rapid—inhalation! delivers!the!medication!directly!to!the!desired!site!of!action,!avoids!firstpass!metabolism! • Disadvantages:!problems!regulating!exact!dosage!! • Ophthalmic!! • Always!administer!to!the!pouch!of!the!lower!eyelid! Blood!flow! • Decreased!circulation!will!result!in!decreased!drug!absorption! Cell!membrane!characteristics!!

Drugs!must!pass!through!the!cell!wall!or!membrane,!which!is!why!the!structure! of!the!cell!wall!influences!absorption! • Drugs!cross!membranes!via!passive!or!active!transport!! • Passive!diffusion:!random!movement!of!drug!molecules!from!high!to! low!concentration! • Drug!molecule!penetrates!along!a!pressure!gradient!! • The!higher!the!concentration,!the!more!rapid!the!diffusion! across!the!membrane! • Active!transport:!moves!molecules!that!are!moderately!sized,!watersoluble,!or!ionic!across!cell!membranes!! • Molecules!form!complexes!with!carriers!for!transport!through! the!cell!membrane! • Requires!energy!and!can!occur!against!concentration!gradient! • Lipophilic!vs!hydrophilic!affects!absorption!across!cell!membranes! • Lipophilic!molecules!pass!through!cell!membranes!better!than! hydrophilic!molecules,!however!most!cell!membranes!are!permeable!to! water!by!diffusion!! • pH!of!a!drug!affects!diffusion! • a!change!in!the!acidity!of!the!stomach!will!affect!absorption!of!drugs! Distribution:!the!transport!of!a!drug!in!body!fluids!from!the!bloodstream!(site!of!absorption)!to! various!tissues!in!the!body! • Phase!1:!movement!from!the!site!of!administration!into!the!bloodstream! • Phase!2:!delivery!of!the!drug!into!the!tissue!at!the!site!of!action!! • Volume!of!distribution!(Vd):!the!description!of!the!amount!of!space!into!which!a!drug! can!be!spread!or!distributed!(theoretical!concept,!not!a!real!volume)àhelpful!in! predicting!drug!concentrations,!understanding!how!well!a!drug!is!absorbed!into!tissues,! and!understanding!whether!it!will!be!accumulated!in!the!tissues! • If!a!drug!has!a!small!Vd,!it!stays!in!the!central!compartment!and!is!not!widely! distributed! • Large!Vd,!it!is!found!widely!throughout!the!body! • Vd=!dose!of!drug/concentration!in!the!blood! • Factors!that!affect!the!volume!of!distribution:!plasma!protein!binding,!obesity,!edema,! and!tissue!bindingàcan$change$as$a$function$of$a$patient’s$age,$gender,$disease,$and$ body$composition! • Geriatric$patients:!less!muscle!and!more!fat,!making!them!at!risk!for! accumulation!of!lipophilic!drugs!in!the!adipose!tissue! • if!patients!lose!weight!and!stay!on!the!same!dose!it!could!be!come!toxic!! • lipophilic!benzodiazepines!are!an!example! • excess!fluid!in!interstitial!spaces!and!dehydration!affect!the!distribution!of! water-soluble!drugs! • alteration!of!normal!muscle-to-fat!ratio—in!obesity!lipophilic!drugs!are! distributed!into!adipose!tissue!and!accumulate! • example:!phenobarbital!is!fat!soluble! •

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can!become!trapped!in!fatty!tissue,!causing!low!blood!levels,! but!these!drugs!are!slowly!released!from!the!fat!into!the! bloodstream! • drugs!that!are!highly!protein-bound!have!the!Vd!similar!to!plasma,!which!is! small! • example:!thyroid!hormones! • if$the$patient$has$a$decreased$serum$albumin,$more$active$drug$is$ available$for$protein-bound$drugs$! • if$two$protein-bound$drugs$are$used,$the$most$tightly-bound$protein$ drug$will$displace$the$other$! • distribution!of!drugs!from!the!bloodstream!to!the!CNS!is!different!than!through!other! cell!membranes!! Biotransformation!(metabolism):!the!chemical!inactivation!of!a!drug!through!conversion!to!a! more!water-soluble!compound!that!can!be!excreted!from!the!body! • Occurs!primarily!in!the!liver,!but!also!in!lungs!and!GI!tract! • Phase!I:!oxidation!or!reduction!of!drugs—making!drugs!more!soluble!so!they!can!be! excreted! • P450!enzyme!system!responsible!for!phase!I!is!present!in!the!liver,!intestines,! and!lungs! • 6!primary!enzymes!and!what!drugs!they!metabolize!are!listed!on!p.!26! • a!drug!can!be!a!substrate,!meaning!it!is!affected!by!alteration!of!the!enzyme! metabolism!OR!an!inhibitor'or'an'inducer,!meaning!it!causes!the!alteration!in! the!enzyme!metabolism! • inhibitor:'causes!the!enzyme!to!metabolize!more!slowly!! • inducer:!causes!the!enzyme!to!metabolize!more!quickly! • **Figure!3-5!is!helpful!for!understanding!the!phases!of!biotransformation**! • Phase!II:!biotransformation—conjugate!reactions!in!which!a!compound!is!added!to!the! drug! • First-pass!effect:!! • When!a!med!is!taken!orally!it!passes!from!intestines!directly!to!the!liver,!which! means!larger!amount!of!medication!is!needed!for!a!sufficient!dose!to!remain! after!the!first!pass!through!the!liver! • Prodrug:!chemical!that!is!pharmacologically!inactive;!it!is!biotransformed!into!a! biologically!active!metabolite!in!the!body! Excretion/Elimination:!process!by!which!drugs!and!their!metabolites!are!removed!from!the!body! • The!liver!and!kidney!are!the!two!major!organs!responsible!for!elimination! • Primarily!the!kidneys! • Remember!if!the!patient!is!in!kidney!failure,!you!need!to!calculate!estimated! creatinine!clearance!to!dose!medications!appropriately! • Drugs!and!metabolites!can!also!be!excreted!through!the!fecal!and!respiratory!route!and! through!breast!milk! • Clearance:'a!measure!of!the!rate!at!which!the!drug!is!removed!from!the!body!OR!the! volume!of!plasma!from!which!all!drug!is!removed!in!a!given!time! •

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*the!body!can!only!eliminate!drugs!if!they!are!in!contact!with!the!eliminating! organ—if!it!is!being!stored!somewhere!such!as!adipose!tissue,!it!cannot!be! cleared!from!the!body! • Steady'state:'there!is!a!stable!concentration!of!the!dug!or!the!drug!is!being!administered! at!the!same!rate!at!which!it!is!being!eliminated! • Therapeutic'range:'area!between!the!minimal!effective!concentration!and!the!toxic! concentration!on!the!plasma!concentration!time!curve! • Half-life:'the!amount!of!time!required!for!the!amount!of!drug!in!the!body!to!decrease!by! one!half!! • Depends!on!the!clearance!and!volume!of!distribution! • Useful!to!estimate!the!amount!of!time!it!takes!to!reach!a!steady!state!of!a!drug! after!a!dosage!regimen!is!started!! • Nonlinear'kinetics:!elimination!dos!not!depend!on!the!dose!or!concentration;!the! amount!of!drug!eliminated!is!constant! • Example:!phenytoin! Principles$of$pharmacodynamics! • Pharmacodynamics!definition:!the!study!of!the!biochemical!and!physiologic!effects!of! drugs!on!the!function!of!living!organisms!and!of!their!component!parts;!“what!the!drug! does!to!the!body”! Mechanism!of!action:!! • Drug!receptors! • A!receptor:!component!of!the!organism!that!binds!to!a!ligand!and!produces!a! change!in!function!in!the!body! • Drugs,!neurotransmitters,!and!hormones!are!known!as!ligands! • Drugs!create!an!effect!through!a!receptor! • Most!drug!receptors!are!proteins! • Drug'affinity:!the!propensity!of!a!drug!to!bind!or!attach!itself!to!a!given!receptor! site! • Agonist:$a!drug!that!has!an!affinity!for!a!stimulated!physiologic!activity!at!cell! receptors!normally!activated!by!naturally!occurring!substances! • Antagonist:$a!drug!that!inhibits!or!counteracts!effects!produced!by!other!drugs! or!eliminates!undesired!physiologic!effects!caused!by!illness;!binds!to!a!receptor! to!inhibit!the!action!of!a!drug!but!has!no!intrinsic!action!of!its!own! • Actions!of!drugs!not!mediated!by!receptors:! • Some!drugs!interact!with!small!molecules!or!ions!in!the!body! • Quantifying!the!drug-receptor!interaction! • Agonist!drug!interactions!with!a!receptor!are!reversible! • Efficacy:'a!drug’s!ability!to!produce!a!therapeutic!or!intended!effect! • Free'drug:!amount!of!drug!in!the!body!that!is!able!to!bind!the!receptor! • Potency:!the!dependency!of!effect!on!its!concentration!! Adverse!drug!reactions!and!side!effects:!

Adverse!drug!reaction:!“a!response!to!a!drug!that!is!noxious!and!unintended!and!occurs! at!doses!normally!used!for!man!for!prophylaxis,!diagnosis,!or!therapy!of!disease,!or!for! the!modification!of!physiologic!function”! • Any!response!to!a!drug!that!is!unfavorable!or!unintended! • Most!occur!as!a!result!of!extension!of!the!desired!pharmacologic!effects!of!a! drug,!often!due!to!variability!in!the!pharmacokinetics!and!pharmacodynamics! seen!in!patients! • Table!3-2!p.!34!shows!risk!factors!for!developing!adverse!drug!reactions! • Side!effect:!an!additional!effect,!desirable!or!undesirable,!of!a!drug!that!is!not!the! primary!purpose!of!giving!the!drug!! Drug!interactions:!! • If!the!drug!has!a!narrow!therapeutic!window,!the!risk!of!a!drug-drug!interaction!is! greater!! • Take!into!account!the!half-life!of!a!drug! • *list!at!the!end!of!p37-!p.38!discussing!p450!enzyme!interactions.!I!doubt!there!will!be!a! question!on!something!this!specific,!but!in!case!there!is!one!you!know!where!to!go!!! • *Box!3-2!on!p.!38:!Drugs!associated!with!serious!adverse!effects! • Food!and!drug!interactions!! • *Table!3-3!on!p.!39-41:!Common!food-drug!interactions! • cigarettes!can!diminish!the!effectiveness!of!medication!or!can!create!other! problems!with!particular!drugs!by!increasing!metabolism! • caffeine!can!also!affect!the!action!of!some!drugs! • Alcohol-medication!interactions:! • Alcohol!can!influence!the!effectiveness!of!a!drug!by!altering!its!availability!! • Acute!dose!of!alcohol:!can!inhibit!the!drugs!metabolism!by!competing!with!the! drug!for!the!same!set!of!metabolizing!enzymes! • Prolongs!and!enhances!the!drug’s!availability!and!increasing!the!risk!for! harmful!drug!side!effects! • Chronic!(long-term)!alcohol!ingestion!may!activate!drug-metabolizing!enzymes,! decreasing!the!drug’s!availability!and!diminishing!its!effects! • After!the!enzymes!have!been!activated,!they!remain!activated!even!in! the!absence!of!alcohol—affecting!the!metabolism!of!drugs! • Can!transform!some!drugs!into!toxic!chemicals!that!can!damage!the! liver!or!other!organs! • Can!magnify!the!inhibitory!effects!of!sedative!and!narcotic!drugs!at!their!sites!of! action!in!the!brain! • P.$42$Table$3-4—specific$dr...