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Pharmaceutical Abbreviations

  1. You should know and be able to use or interpret the BOLD FACED Latin abbreviations and their English meaning. The complete Latin equivalent is not required. This list has been selected from the typical Latin abbreviation listing and represents those abbreviations widely used in veterinary medicine.
  2. You should know and be able to use the various terms for weights and measures for the Metric and Apothecaries' systems. For the Apothecaries' system, you need only know the term "grain" and the relationship between "fluid ounces" and "pint".
  3. You should be able to interconvert between the systems, those relations that are printed below in bold typeface, using the approximate equivalencies. These conversions are commonly used in veterinary medicine and/or everyday living.

Pharma Latin Abbreviations

Abbreviation Meaning Latin
ad.lib. freely as wanted ad libitum
aq. water aqua
b.i.d. twice a day bis in die
cap. capsule capula
c with bar on top with cum
div. divide divide
eq.pts. equal parts equalis partis
gtt. a drop gutta
h. hour hora
no. number numero
O. pint octarius
p.r.n. as occasion requires pro re nata
q.s. a sufficient quantity quantum sufficiat
q4h every 4 hours quaque 4 hora
q6h every 6 hours quaque 6 hora
q1d every day quaque 1 die
q1w every week  
q.i.d. four times a day quater in die
s.i.d. once a day semel in die
Sig., S. write on the label signa
stat. immediately statim
tab. a tablet tabella
t.i.d. three times a day ter in die

Weights and measures used in prescribing and toxicology

The Metric System
1 picogram (pg) 10-12 gram
1000 picograms 1 nanogram (ng) or 10-9 gram
1000 nanograms 1 microgram (ug) or 10-6 gram
1000 micrograms 1 milligram (mg) or 10-3 gram
1000 milligrams 1 gram (g)
1000 grams 1 kilogram (kg)
1000 milliliters (ml) 1 liter (L)
Be able to interconvert all of these values
Prefixes for volumes correspond to those for weight.

IMPORTANT: Know that 1 part per million (ppm) is a frequently used term in toxicology and drug residue discussions. For example, the following are 1 ppm:
1 mg / kg, 1 mcg/g.
An analogy is "Percent" that represents 1 part per hundred, i.e., 1 g/100 g = 1% w/w. The expression "w/w" indicates that the amount of both substances is on a weight basis. It is assumed that ppm is w/w unless otherwise specified.

The Apothecaries' System
20 grains (gr) 1 scruple ( )
3 scruples 1 dram( ) = 60 grains
8 drams 1 ounce ( ) = 480 grains
60 minims (m) 1 fluid dram ( )
8 fluid drams 1 fluid ounce ( )
16 fluid ounces 1 pint (O.)
Know eqivalents in bold faced typed

Conversion Equivalents
  Approximate Exact
1 milligram 1/60 grain 1/65 grain
1 gram 15 grains 15.432 grains
1 kilogram 2.2 pounds* 2.2 pounds*
1 milliliter 15 minims 16.23 minims
1 liter 1 quart 1.06 quarts or 33.8 fluid ounces
1 grain 60 milligrams 65 milligrams
1 dram 4 grams 3.88 grams
1 ounce 30 grams 31.1 grams
1 pound* 450 grams 454 grams
1 minim 0.06 milliliter 0.062 milliliter
1 fluid dram 4 milliliters 3.7 milliliters
1 fluid ounce 30 milliliters 29.57 milliliters
1 pint 500 milliliters 473 milliliters
1 quart 1000 milliters 946 milliliters
1 drop 1 minim  
1 teaspoonful 5 milliliters  
1 dessertspoonful 8 milliliters  
1 tablespoonful 15 milliliters  
Know equivalents in bold faced type.
Note: Where possible, use suitable units rather than decimal fractions, e.g., 10 mg not 0.010 g. When a decimal fraction is used the decimal point must be preceded by a zero, e.g., 0.5 not .5.
* = avoirdupois pound (the one used in the USA!)

Conversion factors for obtaining approximate equivalents

To convert To Multiply by
gr/lb mg/lb 60
gr/lb mg/kg 143
mg/lb gr/lb 0.015
mg/lb mg/kg 2.2
mg/kg gr/lb 0.007
mg/kg mg/lb 0.45
Know conversions in bold typeface