The Drug Prescription

Ma. Minda Luz M. Manuguid, M.D.

The Drug Order / Prescription

Contents of a Prescription:name of medication (generic)amount of medication to be given

(dose)route of administrationfrequency of administrationother information: prescribing

physician’s name, signature, license no., PTR no., S2 no. if applicable; date; patient’s name, age, etc.,

John dela Cruz 36y/o M/M

1135 Quezon Drive, Dau

08 Jan 2010

RxHydroxyzine 25 mg tab #20 (ITERAX)

Sig: 2 tabs q d, h.s.

mlmanuguid m.d.

lic no. 58244

PTR # 0687226

frequency abbreviation

explanation

every day q. d. q. – Lat. – quisque = everyd. – Lat – diem = day

every other day

q. o. d. o - other

every hourevery 2 hrsevery 3 hrs.etc.

q. h.q. 2h.q. 3h.etc.

h – hora = hour

2x a day3x a day4x a day

b. i. d.t. i. d.q. i. d.

b. – bi = twice t. – tri = thrice q. – quad = four times

as much as required

q. s. q. – quantitys. - sufficient

frequency

abbreviation

explanation

every morning

q. a. m. q. – everya. – ante = beforem. – meridiem = noon

at bedtime

h. s. h. – hora = hours. – somni = sleep

before meals

a. c. a. – ante c. - cibum = meal

after meals

p. c. p. – post = afterc. – cibum = meal

as desired

ad lib ad libitum = at one’s pleasure

frequency abbreviation

explanation

as necessary

s. o. s. si opus sit = if it is necessary

as needed p. r. n. pro re nata = as occasion requires

immediately

stat statim - immediately

with c cum = with

before a ante = before

after p post = after

abbreviation

explanation

p.o. per orem = by mouth

iv intravenous

im intramuscular

subQ; sq subcutaneous

mg milligram

mcg microgram

IU International units

Drug Dosageparenteral meds: units of measurement:

units/hr.; mg./hr.; mg./min.; mcg/min.; mcg/kg/min

formula : dose = rate x concentrationnonparenteral meds –

capsules & unscored tablets are rounded to the nearest whole tablet

Scored tablets are rounded to the nearest ½ tablet Liquid meds are rounded to one decimal place (tenth)

parenteral meds Intradermal inj – 0.1 ml. or less Subcutaneous – 1.0 ml or less Intramuscular – 1.0 ml or less for older infants & young children;

2.0 ml or less for elderly thin adults & children; up to 3.0 ml in large muscles in well-developed adults

Dosage calculations

Rate – always in ml./hr.Ratio & Proportion – equations

containing ratios of equal value separated by colons or written as fractions. e.g. 2 : 6 = 4 : 12 – the two inner numbers, 6 & 4, are the “means”; the two outer numbers, 4 & 12, are the “extremes”. The product of the means must equal the product of the extremes.

Calculations Intravenous calculations – drop factor

macrodrop – factor of 10, 15, or 20 drops per ml microdrip – 60 gtts/ml

Formula for calculating iv flow rate (ugtts):V1/T1 = V2/T2 where V1 – volume to infuse; T1 – time to infuse;

V2 – drop factor; T2 - time in minutes e.g. 200ml D5LR to be infused within 4

hrs. 200/4hrs = 12000 ugtts/240 mins = 150ugtts/min

Calculations

600 ml to be infused within 3 hrs. 10 gtts/ ml : 600ml = 6000 gtts; 3 hrs = 180 min

• 6000 gtts / 180 mins = 33 gtts/min 15 gtts/ml : 600 ml = 9000 gtts;

• 9000 gtts / 180 min = 50 gtts/min 20 gtts/ml : 600 ml = 12000 gtts

• 12000 gtts/180 min = 67 gtts/min

Pediatric Calculations

Based on body surface area BSA is determined from a normogram Formula: child’s BSA /1.7 sq. m. x adult dose

Based on body weight: Convert child’s weight to kg. (1 kg. = 2.2 lb) Calculate the medication dose, then the daily dose, then

divide the daily dose by the number of doses/day

Pediatric calculations e.g. Amoxycillin : 30-50 mg./kg. body wt

prep: gtts 100mg/ml patient : 6 month old baby boy weighing 11 lbs

convert lbs to kg (11 lbs ÷ 2.2 = 5 kg) compute total daily dose

(5kg x 30-50mg/kg = 150-250 mg) divide total daily dose into 3

(150 – 250 mg ÷ 3 = 50-80 mg) compute amount of medicine(0.5-0.8 ml.)= dose TID

Thank You !