NCMA113 LEC: DOSAGE AND COMPUTATION (SIR ACENA)
DOSAGE AND COMPUTATION Example (prn):
- Nurses are often intimidated by the math that occurs in every You have patient that always complain of abdominal pain now
practice in most clinical and academic settings nurses must you reffered him/her to the doc. and the doctor ordered:
demonstrate a 100% accuracy with medication dosage because - Buscopan 10 mg 1 tab prn for abdominal pain
patient safety depends on practitioners ability to calculate - Buscopan 10 mg 1 tab prn q 4 hrs. for abdominal pain
medications correctly in timely manner. - In the first example, you can give Buscopan when
- Patient safety is a key concern for nurses; ability to calculate necessary, but the 2nd example you can give Buscopan
drug doses correctly is an essential skill to prevent and reduce whenever necessary, but the nurse must observe a 4-hour
medication errors. interval between doses. If the client is still in pain and the
Common Medical Abbreviations Related to Medication 4-hour interval is not yet done, the nurse can re-assess the
Routes client and can refer the client’s severity of pain to the
Routes – kung saan natin pinapadaan yung mga gamot papunta sa doctor.
katawan ng pasyente. q- every
IM– Intramuscular (Intra – within/ inside, w/in the q4 hrs.- every 4 hours. The drug is given at (4am-8am-12nn-
muscles) 4pm-8pm-12mn). The drug is given 6x a day (24 hrs. divided
IO– Intraosseous (directly into the bone marrow) by 4 hrs.) or RTC (Round-the-clock)
IV– Intravenous (vein) q6 hrs.- every 6 hours. The drug is given at (6 am-12nn -6pm-
IVP– Intravenous Push (blood stream/ vein) 12 mn). The drug is given 4x a day (24 hrs. divided by 6
ID – Intradermal (under the skin) hours) or RTC.
IN – Intranasal (nose) q8 hrs - every 8 hours. The drug is given at (8am-4pm-12mn).
IP – Intraperitoneal (within peritoneum or the walls of The drug is given 3x a day (24hrs divided by 8) or RTC.
abdominal cavity.) p.o.- per orem or by mouth
IT – Intrathecal (spinal canal, subarachnoid space so it SL- sublingual- the medication is placed under the tongue.
reaches the CSF, useful in anesthesia, chemotherapy, pain o.d. - occulus dexter or right eye
management) o.s. - occulus sinister or left eye
IVPB – Intravenous piggyback ( sometimes called o.u. - occulus uterque or both eyes or each eye
secondary IV infusion) a.d. –right ear
p.o – By mouth a.s. - left ear
SC / SubQ – Subcutaneous a.u. both ears
SL – Sublingual (under the tongue) HS - hours of sleep, at bedtime or half strength
top. – Topical (on the skin) mg- milligrams
Supp – suppository (rectal) by insertion to a body gm or G- gram
pess – pessary, Vaginal suppository gr- grain
Measurement ml-milliliter
Kg– kilogram cc-cubic centimeters
gm– gram L -liter
mg– milligram Neb -nebule
mcg– microgram Amp -ampule
mEq- milliequivalent Tsp -teaspoon
L– liter tbsp. -table spoon
mL– milliliter ODBB- once a day before breakfast
μg– microgram R – refused
gtt – drop NA - not available
μgtt – micro drop Syr – syrup
tbsp – tablespoon Susp – suspension
tsp – teaspoon Elix -elixir
mg/dL – milligrams per deciliter Supp - suppository (rectal)
Medical abbreviations Pess - vaginal suppository
OD- once a day - the drug is given at 8 am or 9 am unless Gtt - drop; gtts- drops
specified by the doctor. a – before
BID- twice a day- the drug is given at 8 am and 6 pm ac –before meal
TID- thrice a day- the drug is given at 8 am, 12 nn or 1pm and cap. -capsule
6 pm. hs or HS –at bedtime: Hours of sleep
QID- four times a day- the drug is given at 8am, 12nn, 4pm MDI –metered dosage inhaler
and 8 pm P –after
prn- whenever necessary/needed, no specific time unless time Rx –prescription
interval is specified by the doctor. stat –immediately
Tab –Tablet
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FUNDAMENTALS OF NURSING PRACTICE LEC: WEEK 3 – DOSAGE AND COMPUTATION (SIR ACENA)
Tx –Treatment lb ←kg ( x by 2.2 )
FR –Fast Release
TR –Timed-Release lb kg ( ÷ by 2.2 )
XR –Extended Release
Conversion
Volume
Liter to mL L → mL (multiply by 1,000) big to small
Example: How many mL in 5 Liters?
Computation: 5 liters x 1000 = 5000 mL
mL to Liter mL → L (divide by 1,000) small to big
Example: How many liters in 3000 mL?
Computation: 3000 mL ÷ 1000 = 3 L
Time
Hour to minutes hr → min (multiply by 60)
Example: How many minutes in 3 hours?
Computation: 3 hours x 60 = 180 minutes
minutes to hour min → hr (divide by 60)
Example: How many hours in 120 minutes?
Computation: 120 minutes ÷ 60 = 2 hours
Calculating Tablet Dosages
desired dosage
ൌ number of tablets
stock dose
Used in identifying how many tablets you will give to the patient
Desired dosage is the ordered dosage of the physician.
Stock dose is the amount of drug present in each tablet.
Example:
The physician orders 500 mg of Amoxicillin tablet TID for the
patient. The drug is available in 250 mg tablets. How many tablets
should be given to the patient?
500 mg
ൌ 2 tablets
250 mg
Example 2:
The physician orders 1g of Paracetamol tablet prn for the patient.
The drug is available in 500 mg tablets. How many tablets should
be given to the patient?
1g x 1000= 1000mg
Mass
Kg g mg mcg ( x by 1,000 ) big to smallest
Example:
1 Kg to g? [ 1 kg x 1000 = 1000g]
3 g to mg? [ 3 g x 1000 = 3000 mg]
5 mg to mcg? [ 5 mg x 1000 = 5000 mcg]
mcg mg g kg ( ÷ by 1,000 ) small to biggest
500 mcg to mg? [ 500mcg ÷ 1000 = 0.5 mg ]
1000 mg to g? [ 1000 mg ÷ 1000 = 1 g ]
250 g to kg? [ 250 g ÷ 1000 = 0.25 kg ]
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FUNDAMENTALS OF NURSING PRACTICE LEC: WEEK 3 – DOSAGE AND COMPUTATION (SIR ACENA)
Calculating Mixtures and Solutions
desired dosage
x stock volume ൌ amount of soltion to be given
stock dose
Stock volume
- the amount of the solution where the drug is diluted.
- is the amount of the solution where the drug is diluted or
the amount of sterile water to dissolve powder-based
meds.
Example 1:
The physician orders 500 mg of Ceftriaxone q8 for the patient. The
drug is available in 1 g vial. You plan to dilute it in 10 mL of
sterile water. How much should you give to your patient?
500 mg
x 10 mL ൌ 5mL
1000 mg
10ml- diluted medication
5ml= 500ml, ito lang kukunin para i-inject sa pt.
Kung gaano karami ung kukunin liquid/medication ganun din
karami air na ilalagay sa syringe
Example 2:
The physician orders 5 mg of Metoclopramide prn for the patient.
The drug is available in 10 mg per 2 mL preparation. How much
should you give to your patient?
5 mg
x 2 mL ൌ 1mL
10 mg
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