Transcript K1. Dose Calculation

What’s in YOUR scope ?
DOCTOR
PHARMACIST
NURSE
Diseases
diagnosis
Drug therapy
Care plan
GOAL ?
HOW TO GET (Y)OUR
COMPETENCY :
- Diseases & its cause
- Drug & its therapy
- Patient & the treatment
Your focus is here !!!
But u can’t left the 2 other ya ^^
NICE QUOTE :
“Terapi Pengobatan yang efektif dan aman
hanya dapat dicapai
bila pasien mengetahui
seluk beluk pengobatan dan kegunaannya“
This is our JOB !!!
DRUG
DRUG MECHANISM
DRUG INTERACTION
DOSE & CALCULATION
HOW TO ADMINISTER DRUG
TYPE / CLASS OF DRUGS
Drugs Calculation
Reference :
Tambayong, Jan,dr., 2001, Farmakologi untuk
Keperawatan, Widya Medika, Jakarta.
Wallace, Laurence B ; Guide for Calculating Medication.
www.jsu.edu/nursing/linkdocs/DrugCalc/NU325.pdf
Starkings, Susan ; Drug Calculation and The
Mathematics Required for Nursing.
www.health.heacademy.ac.uk/rp/resources/articles/sst
arkings
Household System VS Metric System
VS Apothecaries System
Household : lbs, c, inch, tea spoon, glass, etc
Metric : ml, g, gr, kilo, centi, dexa, etc
Apothecaries : fl oz, cc, etc
1 kg = 2.2 lbs
Grain  gr 1 = 60 mg
Fluid ounces  1 fl oz (US) = 29.57353 ml
*check USP, FI
ACCURATE ?
VS
CONVERSION
EXAMPLE :
RATIO  PERCENT
1 : 5 = …. %
1
2
------ X ------ =
100
100
2
----------10.000
1 : 2000 = …. %
PERCENT  RATIO
0,02 % = … : …
1,5 % = … : …
1
----------5.000
What is that mean?
Is it Solid or Liquid ?
-If it’s SOLID = gram
-If it’s LIQUID = mililiter
5%=
5g
--------- X 1 = 0,05 g/g = 50 mg/g
100 g
HOW TO CALCULATE ?
Simple Three-Step Approach to Dosage Calculations:
Step 1: Convert : Ensure all measurements are in the
same system of measurement and the same size unit of
measurement. If not, convert.
Step 2: Think WHAT’S AVAILABLE : Estimate what is a
reasonable amount of the drug to be administered.
Step 3: Calculate : Apply the formula:
I x Jt
=X
T
* I = dosis yg diminta , Jt = Jumlah tersedia , T = dosis yg tersedia , X = hasil
Oral Dosage
How many Digoxin tablets that you need to get 0,125
mg ? *each tablet contain 62,5 mcg Digoxin
0,125 mg = (0,125 x 1000) mcg = 125 mcg
I x Jt
=X
T
125 mcg / X tab
125 mcg x 1 tab
------------------------ = ------------------------- = 2 tab
62,5 mcg / 1 tab
62,5 mcg
Injection Dosage
The physician ordered Phenobarbital 30 mg. you
have on hand an ampule of Phenobarbital
containing 60 mg per 5 ml. how many ml of
medication will you give?
I x Jt
=X
T
30 mg / X ml
30 mg x 5 ml
------------------ = --------------------- = 2,5 ml
60 mg / 5 ml
60 mg
Injection Dosage
The physician ordered Morphine 4 mg IM. You have
Morphine containing 10 mg in 2 ml. How many ml
should you give? Chose the correct syringe and
shade in the appropriate amount of medication.
I x Jt
=X
T
4 mg / X ml
4 mg x 2 ml
------------------ = -------------------- = 0,8 ml
10 mg / 2 ml
10 mg
Intravena Dose (infusion rate)
Formula for Calculating Intravenous Fluids
total ml fluid to be given
1. ml/hr  -------------------------------- = desired ml/hr
hours to be infused
desired volume x drop factor
Jumlah tetesan / ml larutan
2. drops/min  ------------------------------------- = desired gtts/minutes
total number of minutes
Infusion Dosage
Physician orders 2000 ml of fluids to infuse in 16
hours. You have available the Baxter administration set
with drop factor of 10. how many cc/hour should fluids
infuse? And how many drops/minutes?
Desired volume : 2000 ml
Drop factor : 10
Total number of minutes = 16 hour = 16 x 60 minutes =
960 minutes
ml/hr
Hour = jam
total ml fluid to be given
ml/hr  -------------------------------- = desired ml/hr
hours to be infused
2000 ml
-------------- = 125 ml/hr = 125 cc/hr
16 hr
* 1 cc = 1 ml
drops/minutes
desired volume x drop factor
drops/min  ------------------------------------- = desired gtts/minutes
total number of minutes
2000 x 10
--------------- = 28,3 gtts/minutes
960
Pediatric dosages
RULE : to verify safe pediatric dosing
1.convert the child’s weight (if it’s different)
2.calculate the safe dosage in mg/kg or mcg/kg as
recommended
3.Compare the ordered dose to the recommended
dose and decide if the dosage is safe
How to convert Adult Dose to
Child Dose (pediatric) ?
RUMUS MENGHITUNG DOSIS:
CLARK : w/70 x DM Dewasa
YOUNG : w/(n+20) X DM Dewasa
DILLING : n/20 X DM Dewasa
COWLING : (n+1)/24 X DM Dewasa
FRIED : m/150 X DM Dewasa  dosis Bayi
Keterangan :
W = Berat Badan ( Kg )
n = Umur ( tahun )
m = Umur ( bulan)
DOSIS OBAT
Dosis suatu obat : adalah dosis pemakaian sekali untuk peroral atau
injeksi,Dalam pemberian terapi obat yg rasional
DOSIS TERAPI (DT)
Dosis individual yg tertulis di resep dg tujuan pengobatan
DOSIS LAZIM (DL)
Dosis yang tercantum di literatur yg lazimnya dapat menyembuhkan, dosis
tersebut sebagai acuan dalam menetapkan dosis terapi per individual Contoh
: Erithromicin
Sekali minum : 250 mg – 500 mg
Seharinya : 1000 mg – 2000 mg
DOSIS MAKSIMUM (DM)
Dosis terbesar yg dpt memberikan efek terapi tanpa menimbulkan bahaya
Contoh : Erithromicin
Sekali minum : 500 mg
Seharinya : 4000 mg
How to convert Adult Dose to
Child Dose (pediatric) ?
Berdasarkan Luas Permukaan Tubuh (BSA)
LUAS PERMUKAAN TUBUH (m2)
DOSIS PEDIATRI = ------------------------------------------------- x Dosis Dewasa
1,73
See : Pediatric Dose Chart
Example :
The physician orders morphine sulfate 1.8 mg IM stat. The child weighs 79 lb. Is this
dosage safe?
Step 1: Convert lbs. to kilograms (2.2 lb. = 1 kg)
79 / 2.2 = 35.91 or 35.9 kg.
Step 2: Calculate mg/kg as recommended by a reputable drug resource. (A
reputable drug resource indicates that the usual IM/SC dosage may be
initiated at 0.05 mg/kg/dose.)
Per dose= 35.9 kg x 0.05 mg = 1.79 mg = 1.8 mg/dose
Step 3: Decide if the dosage is safe by comparing ordered and recommended
dosages. For this child’s weight, 1.8 mg is the recommended dosage and 1.8
mg is the ordered dosage. Yes, the order is safe.
EXAMPLE :
The physician’s order reads “Keflin” 1000 mg. IV
q6hrs.” The PDR gives the dosage range as 5080 mg. per kg. per day to be given in divided
doses of q 8 hours. The child weighs 32 pounds.
? Is the dosage ordered in the safe range?
_____If so, How many mg should be given per
dose? _____________
Answer :
The PDR gives the dosage range as 50-80 mg. per kg.
per day to be given in divided doses of q 8 hours. The
child weighs 32 pounds.
32 lbs = …. Kg  32 / 2.2 = 14.5 kg
recommended dose =
50-80 mg/kg/day  50 mg/kg/day x 14.5 kg = 725 mg/day
80 mg/kg/day x 14.5 kg = 1160 mg/day
Cont…
The physician’s order reads “Keflin” 1000 mg. IV q6hrs
recommended dose = 725 mg/day – 1160 mg/day
it means that the dosage is NOT in the safe range.
How many mg should be given per dose?
if 1000 mg / day = …… mg/ 6 hours
1000 mg / 24 hours 1000 mg x 6 hours
---------------------------- = ----------------------------- = 250 mg q6hrs
X mg / 6 hours
24 hours
Next question :
Download on …….
TRY TO ANSWER THIS :
A 50-pound child is to receive 0.2 mg/kg. How many mg. of
a medication is the correct dose for this child?
Albuterol 1.2 mg po t.i.d. for an 18 kg child with severe
asthma. Recommended dosage from the manufacturer:
0.2mg/kg/day orally in three equally divided doses. Is the
order safe?
Ordered: Dilantin 30 mg T.I.D. PO for a 2 year old child
weighing 39.6 pounds. Safe dose for this age group is
5mg/kg/day. On hand is Dilantin Pediatric Suspension
125mg/5ml. How many ml. would you give per dose?
ALHAMDU….. LILLAH…