If an animal _____ or is ___________ by a miscalculated drug dose, the veterinarian and veterinary nurse who miscalculated the dose would potentially be legally liable for the animals death
dies, injured
Always _________ __________ drug dosages!
double check
What is the basic unit of mass of the metric system?
gram (milligrams, kilograms)
Apothecary system: mass is measured in ______ and volumes in _______ _________
grains, fluid ounces
Household system is based on:
common household units of measurement (tablespoon, pint, gallon, pound)
Metric systems uses units of:
10, 100, 1000, 1/10 with different prefixes
1 microgram (mcg) = ______ g
0.000001 g
1 microgram (mcg) = _______ mg
0.001 mg
1 gram = ______ mg
1,000 mg
1 gram = _______ ug
1,000,000 ug
1 kg = ________ g
1,000 g
Volume base unit:
liter (microliters, milliliters, kiloliter)
1 milliliter = ________ L
0.001 L
1 liter = ______ mL
1,000 mL
1 mL = _______ ug
1,000 uL
1 uL = _____ mL
0.001 mL
Length basic unit:
meter (millimeters, kilometers)
1 kg = ___ lbs
2.2 lbs
1 kg = ____ g
1000 g
1 kg = ___ mg
1,000,000 mg
1 g = ____ mg
1000 mg
1 g = ___ kg
0.001 kg
1 mg = ___ g
0.001 g
1 mg = ___ micrograms
1,000 ug or mcg
1 lb = ___ kg
0.454 kg
1 lb = ___ oz
16 oz
1 grain (gr) = ___ mg (household system)
64.8 mg
1 gr = ___ mg (apothecary)
60 mg
1 L = ___ mL
1000 mL
1 L = ___ deciliters (dL)
10 dL
1 mL = ___ cc
1 cc
1 mL = ___ microliters
1000 ul or mcL
1 tbsp = ___ tsp
3 tsp
1 tbsp = ___ mL
15 mL
1 tsp = ___ mL
5 mL
1 gal = ___ L
3.786 L
1 gal = ___ qt
4 qt
1 gal = ___ pt
8 pt
1 pt = ___ cups
2 c
1 pt = ___ fl oz
16 fl oz
1 pt = ___ mL
473 mL
Any time the conversion made between two adjacent units in the relationship of kg > g > mg > mcg the decimal point will be moved _______ places
three
To determine a dose needed for an animal , the following information is needed:
animals weight, recommended dosage of the drug for this animal species, drug concentration
Dose =
animals weight x dosage rate
__________________________________________
concentration of drug
1 lb = ___ kg
0.454 kg
1 kg = ___ lbs
2.2 lbs
Multidose vials
may have concentration of 5 mg/ml
Solid forms
200 mg tablet has 200 mg of drug delivered to the animal with each tablet taken
Liquid forms
usually expressed as % solution, typically the number of grams of drug in 100 mL of liquid (ex. a 1% solution would have 1 gram of drug in each 100 ml liquid withdrawn)
Calculate the dose of Baytril needed for a 20 lb French Bulldog. The dosage is 5 mg/kg PO q12h x 7d. Your veterinarian has 25 mg tablets on hand.
20 lbs / 2.2 lbs = 9.09 kg
9.09 kg x 5 mg/kg = 45.4 mg
Dosage = 45.4 mg PO q12h x 7d
or 2 tablets PO q12h x 7d
2 tablets PO q12h x 7d. How many tablets would be dispensed?
2 tablets/dose x 2 doses/day x 7 days = 28 tablets dispensed
If 42 lb dog is ordered to get 2 mg/kg tid for 7 days
Tablet size = 60 mg
1. first calculate weight of animal
42 lb x 1 kg/2.2 lbs = 19.1 kg
2. then calculate dosage
19.1 kg x 2 mg/kg = 38.2 mg of drug per dose
3. then calculate total for 7 days
38.2 mg drug/dose x 3 doses/day x 7 days = 802.2 mg total
802.2 mg x 1 tablet/60 mg
If a 20 kg dog is to be given amoxicillin at the rate of 10 mg/kg, and injectable amoxicillin at a concentration of 100 mg/ml is available, the dosage calculation would be:
Dose = 20 kg x 10 mg/kg 200 mg
------------------- = ------------ = 2 ml
100 mg/ml 100 mg/ml
If the order is to give a dog 300 mg of amoxicillin (concentration 100 mg/ml), the calculation would be:
300mg
------------ = 3 ml
100 mg/ml
The dose of most drugs used to treat neoplasms/cancer is calculated according to the total body surface area of the patient. Body surface area is correlated with the weight of the animal
ex. kg m2
0.5 0.064
5.0 0.295
20 0.744
Dose = mg/m2 (from insert) x
0.295 m2 x 20mg/m2 = 5.9 mg
Solutions
mixtures of substances that usually are not chemically combined with each other
Solutions are made up of a dissolving substance called the __________ and a dissolved substance called the ________
solvent, solute
Concentrations may be expressed in a number of ways including:
-parts
-weight per volume (w/v) for liquids
-volume per volume (v/v) for liquids -most common
-weight per weight (w/w) for solids
Concentration:
the amount of solute dissolved in solvent
Concentration is reported as:
percents or percent solution
Parts
ppm (parts per million) means 1 mg of solute in a kg or L of solvent
What is the percent concentration of 1:1000 epinephrine?
Divide the 1 by 1000 and multiply by 100 (1/1000)(100) = 0.1% solution
Liquid in liquid
-% concentration is the volume per 100 volumes of the total mixture
-can be expressed in any unit as long as both numerator and denominator units are the same
(2mL/100mL, 6L/100L, 7oz/100oz)
Solids in solids
-% concentration is the weight per 100 weights of total mixture
-can be expressed in any unit as long as both numerators and denominator units are the same
(60mg/100mg, 6g/100g, 16oz/100oz)
Solids in liquids
-% concentration is the weight in grams per 100 volume parts in milliliters
-the weight must be in grams and the volume must be in milliliters
(5% dextrose = 5g/100mL or 50mg/ml)
Solutions (concentration of a solution is weight (mg, IU, gr) per volume (ml))
conversion factor: X% = X g/100 ml
How many mg/ml are there in a 2.5% solution?
-convert g to mg by multiplying by 1000
2.5g/100ml x 1000mg/1g = 2500mg/100ml
-simply by dividing each by 100 = 25 mg/ml
Percent means:
parts of solute per 100 parts of the solution
Problems involving a change of the solution
volume one x concentration one = volume two x concentration two
For gravity feed drips, it is usually most convenient to count:
the number of drops rather than determine the ml being delivered
Formula that calculates the total fluid replacement per hour, which is sometimes how the infusion pump is set
10 ml/kg/hr (surgical fluid replacement rate)
How would you prepare 100 ml of a 5% dextrose solution from 50% dextrose solution?
V1 x C1 = V2 x C2
100 x 5 = 50 x (V2)
10 = V2
Another method: desired strength = amount to use
------------------ -----------------
available strength amount to make
using last problem
5 x
--- = ---
50 100
x = 10 ml
Volume of infusion (ml)
-------------------------- x drop factor (gtt/ml) =
Time of infusion (min)
drops per minute
1 gtt = ___ drops
1 drop
Give 480 ml of lactated ringer's solution to Dog A over a 4-hour period using a standard 15gtt/ml administration set
480 ml 2 ml 15 gtt 30 gtt 1 min 1 gtt
-------- = ------ = ------ = ----- x ------ = ----
240 min min ml min 60 sec 2 sec
Drop size
-regular IV drips have a drop size that is equal to between 10-20 drops per ml. If in doubt an average of 15 drops per ml can be used
-microdrips have a small drop size and deliver 60 drops per ml
How can you usually recognize microdrips?
recognized by the small metal tube in the drip chamber
When the drip rate falls below 1 drop in 2 seconds, a gravity feed drip tends to experience problems with ____________. (In this case, use a microdrip to deliver more drops per second)
clotting
Constant Rate Infusion (CRI)
-sometimes medications given by intravenous infusion have to be administered at a dose delivered at a constant rate over a specified period of time. The dosage is often ordered in micrograms (ug) per kilogram per minute
-this dosage can be confusing becau
Drip rates may be calculated as:
(wt kg) (10 ml/kg/hr) (drops/ml)
-----------------------------------
3600 seconds per hour
0.6 dr/sec = 6 drops in 10 seconds
What is the drip rate for a 20 kg dog going to surgery using a 60 gtt/ml drip set and administering 10mg/ml/hr of fluids?
gtt/ml = (20kg) (10ml/kg/hr) (60 gtt/ml)
----------------------------------
3600 seconds per hour (sph)
3.33 gtt / 1 sec
Gravity Air-Displacement Sterilizer
-Table top autoclave
-Temperature: 250�F to 270�F
-Pressure: 15 to 27 lbs per square inch (psi)
-Cycle: 15 to 30 minutes depending on the item
-If the autoclave does not have a drying cycle, once the item has been sterilized, crack open the door for at le
Calculation of CRI
(dose) (weight in kg) (minutes)
---------------------------------
concentration
Ketamine CRI is 2 to 20 ug/kg/min
For a ketamine CRI of 3 ug/kg/min (0.003 mg/kg/min) for a 30 lb dog (13.6 kg) over a period of 6 hours if the concentration of the drug is 100mg/ml
(3 ug/kg/min) (13.6 kg) (6 hr) (60 min)
------------------------------------------
(100 mg/ml) (1000 ug/mg)
= 0.14 ml of ketamine