chapter 9.odt

8/10/2019 chapter 9.odt

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HAPTER 9

B

ASI

M

EDI ATION AL ULATIONS

A student enters a pharmacy and asks, "Do you have a pill for math?" Thepharmacist says "Wait just a moment", and goes back into the storeroom and

brings back a whopper of a pill and plunks it on the counter "! have to take thathuge pill for math?" inuires the student The pharmacist replies "Well, youknow math always was a little hard to swallow"

##$nknown Author

This chapter is intended to proide an oerie! o" so#e $asic concepts ino%ed in phar#ac& #athinc%'din()

ca%c'%atin( dosa(es !hen (iin( #edications in ta$%et or caps'%e "or#*

ca%c'%atin( dosa(es !hen (iin( #edications in %i+'id "or#* and

percenta(e stren(th o" so%'tions,

An i#portant thin( to -eep in #ind !hi%e doin( this chapter is that #an& o" the concepts ta'(ht in thissection !i%% sti%% $e app%ied in the co#in( !ee-s,

Calculating Dosages When Giving Medications in Tablet or Capsule Form

On a re('%ar $asis* &o' !i%% need to "i('re o't ho! #an& ta$%ets or caps'%es to dispense, Thesepro$%e#s are 's'a%%& #ade easier !ith the ./ Step Method0 and di#ensiona% ana%&sis, e& thin(s to%oo- "or are) the +'antit& o" #edication per dose* the stren(th o" the ta$%et* ho! o"ten the doses are$ein( (ien* and ho! %on( o" a ti#e "ra#e !e need to coer !ith these doses, 2o' #a& need to inc%'deso#e conersion "actors,

3itho't !antin( to oer e4p%ain the process* %et5s %oo- at an e4a#p%e pro$%e# on the ne4t pa(e !here!e 6'st !ant to "ind a n'#$er o" ta$%ets needed per dose,

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%&ample

A 188 #( dose o" #edication is ordered* and the ta$%et sie aai%a$%e is 7/ #(, Ho! #an& ta$%ets !i%%$e needed per dose:

;UESTIONHo! #an& ta$%ets !i%% $e needed per dose:

DATA

'((mgd o s e

)*mgt ab le t

METHOD

> caps


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ractice roblems

Ca%c'%ate the n'#$er o" caps'%es or ta$%ets needed per dose,

1? @88 #( ordered /8 #(


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Besides 6'st "i('rin( o't ho! #an& ta$%ets or caps'%es !e !i%% need "or a partic'%ar dose* !e !i%% needto %oo- at ho! #an& !e need to coer a partic'%ar ti#e "ra#e in order "or 's to proide a s'""icient+'antit& "or the patient, Most instit'tiona% settin(s proide #edications in 7 ho'r incre#ents* a%tho'(hthis #a& ar& $et!een ario's instit'tions,

%&ample

I" (r t,i,d, is ordered and 188 #( caps'%es are aai%a$%e* then !hat is the tota% n'#$er o" caps'%es

needed per da&:

;UESTION3hat is the tota% n'#$er o" caps'%es needed per da&:

DATA

*g r

dose

-d o se s

da y

'((mg

c ap

And &o' !i%% need a conersion "actor "or (rains to #i%%i(ra#s* !hich is either).(mg

gror .*mg

grMATHEMATICAL METHOD < =ORMULA

di#ensiona% ana%&sisDO THE MATH

* g r

d o s e- d o s e s

d a y.( m g

g rc a p

' (( m g =/ c a p s u l e s /d a y

DOES THE ANS3ER MAE SENSE2es

In the a$oe scenario &o' needed to 'se >8 #(


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ractice roblems

A ph&sician orders 98 #( +,h, o" a #edication and &o' hae (r ss


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718


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Worksheet 9-1

Na#e)

Date)

Ca%c'%ate the n'#$er o" caps'%es or ta$%ets needed "or the "o%%o!in( doses,

1?I" 788 #(


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17?I" (r 44


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Ca%c'%ate the n'#$er o" caps'%es or ta$%ets needed to "i%% the "o%%o!in( prescriptions,

71? R4 A#$ien / #(


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71


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ractice roblem

A ph&sician orders aithro#&cin /88 #( I, In the phar#ac& &o' hae 7/8 #(


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di""erent than !hat !e hae a%read& $een doin( !ith other %a$e%s #(* (r* etc,?, Let5s ta-e a #o#ent and%oo- at an e4a#p%e pro$%e# 'sin( 'nits,

%&ample

*888 'nits o" a dr'( is ordered, A 18 cc ia% containin( 18*888 'nits888 'nits ordered /888 'nits


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di%'ent, The reconstit'ted ia% contains 788*888 'nits


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Worksheet 9-!

Na#e)

Date)

Ca%c'%ate the +'antit& o" o%'#e that needs to $e !ithdra!n "ro# the "o%%o!in( ia%s to "i%% theirorders,

1?/ #( o" dr'( ordered a 18 cc ia% !ith a concentration o" 188 #(


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11?A ph&sician orders 1>7,/ #( o" #ethotre4ate* and the 18 #L stoc- ia%s in the phar#ac& hae aconcentration o" 7/ #(


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The reconstit'ted so%'tion no! contains 788*888 'nits


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777


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"ercentage #trength #olutions

There are #an& !a&s to e4press the concentration o" a dr'( one o" the #ost co##on is percenta(estren(th hint3 remember that 4percent5 means 4per '((5? ,

There are three -inds o" percenta(e stren(th that &o' !i%% "re+'ent%& 'se !hen doin( dosa(eca%c'%ations)

$eight%$eight!

Weight%Weight &$%$'

A !ei(ht

'(K='( g 6 i n c o & i d e

'(( g o i n t m e n t

MATHEMATICAL METHOD < =ORMULARatio Proportion This can $e done other !a&s* $'t this is the easiest #ethod to e4p%ainthoro'(h%&,?

DO THE MATH

1

')( goi nt ment=

' ( g 6 i n c o & i d e

'((goint ment

1=' ) g 6 i n c o & i d eDOES THE ANS3ER MAE SENSE:

2es

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Let5s %oo- at a co'p%e o" practice pro$%e#s $ased on !

ractice roblem '

3hat !o'%d $e the percenta(e stren(th o" a inc o4ide oint#ent i" &o' prepared 98 (ra#s o" anoint#ent that contained / (ra#s o" inc o4ide: 78int3 !n this problem you have the weight of the activeingredient and the weight of the mi&ture 9ou need to find the percentage strength which would be outof '(( grams of mi&ture:

;UESTION

DATA

MATHEMATICAL METHOD < =ORMULA

DO THE MATH

DOES THE ANS3ER MAE SENSE:

No!* %et5s %oo- at another !

ractice roblem )

I" &o' !ere to prepare 1/8 ( o" a coa% tar oint#ent containin( 17 ( o" coa% tar* !hat is the percentstren(th o" coa% tar in the oint#ent:

;UESTION

DATA


DO THE MATH


(olume%(olume &v%v'

o%'#e77

/,>K inc o4ide

K coa% tar


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stren(th pro$%e#s* e4cept no! the in(redients are %i+'ids, T&pica%%& it is e4pressed as n'#$er o"#i%%i%iters per 188 #i%%i%iters* $'t it co'%d $e e4pressed in an& 'nit o" o%'#e %iters* pints* "%'id o'nces*etc,? as %on( as the 'nits on the top and $otto# #atch, Loo- at the e4a#p%e pro$%e# $e%o!* and thenco#p%ete the practice pro$%e#,

%&ample

Ho! #L o" isoprop&% a%coho% are in a 8 #% $ott%e o" 8K isoprop&% a%coho%:

;UESTIONHo! #an& #L o" isoprop&% a%coho% are in the $ott%e:

DATA+2( m 0 o f m i & t u r e

;(K i s o p r o p y l a l c o h o l=;( m 0 i s o p r o p y l a l c o h o l

'(( m 0 m i & t u r e

MATHEMATICAL METHOD < =ORMULARatio Proportion This can $e done other !a&s* $'t this is the easiest #ethod to e4p%ainthoro'(h%&,?

DO THE MATH

1

+2(m 0 m i & t ur e=

;(m 0 i s o pr o p y l al c oh ol

'((m 0mi &tu re1=--. m 0 is o p r o p y l al c o ho l

DOES THE ANS3ER MAE SENSE:2es

ractice roblem

Ho! #an& #L o" %&so% !o'%d $e re+'ired to #a-e 888 #L o" a 7K %&so% so%'tion:

;UESTION

DATA


DO THE MATH


Weight%(olume &$%v'

3ei(ht


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%&ample

Ho! #an& (ra#s o" sodi'# ch%oride are in a /88 #L $a( o" 8,9K sodi'# ch%oride:

;UESTIONHo! #an& ( o" sodi'# ch%oride are in the $a(:

DATA

*(( m 0o f mi &t ure (/K s o d i u m c h l o r i d e=( / g s o d i u m c h l o r i d e

'((m 0 m i & t ur eMATHEMATICAL METHOD < =ORMULA

Ratio ProportionDO THE MATH

1

*((m 0mi &t ur e=

( / g s o d i u m c h l o r i d e

' ( ( m 0 m i & t u r e

1=+ * g s o d i u m c h l o r i d e

DOES THE ANS3ER MAE SENSE:2es

As !


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@?Ho! #'ch dr'( is in /8 cc o" a 1K so%'tion:

?Ho! #an& cc o" a 78K so%'tion can $e #ade !ith / ( o" dr'(:

77

1? 78K 7? 7/8 #L @? 8,/ (


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77


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17?Ho! #an& #L o" a 7K so%'tion can $e #ade !ith > ( o" a dr'(:

1@?Ho! #an& cc o" a 18K so%'tion can $e #ade !ith / ( o" a dr'(:

1?3hat !ei(ht o" dr'( is in @8 #L o" a 1/K so%'tion:

1/?A so%'tion o" 8 cc contains /8 ( o" a dr'(, 3hat is the percent concentration o" this so%'tion:

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18? A patient needs /8 #( o" ora% potassi'# ch%oride so%'tion, I" the ora% potassi'# ch%orideso%'tion has a concentration o" 18K* ho! #an& ta$%espoons o" so%'tion sho'%d the patientreceie "or this dose:

7@7


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Worksheet 9-,

Na#e)

Date)

Ca%c'%ate the n'#$er o" caps'%es or ta$%ets needed per dose,

1?1/8 #( o" dr'( ordered / #(?I" 8, (


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17?8 #( o" dr'( ordered 188 #(8 #( o" dr'( ordered 8 #(

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chapter 9.odt