Appendix 2 Conversions, Equivalents, and Abbreviations
Table 1 Metrologic and Pharmaceutical Weights and Measures∗
| The Metric System of Weight |
| 1 microgram (mcg) = 0.000,001 gram (g) (μg) |
| 1 milligram (mg) = 0.001 g = 1000 mcg (μg) |
| 1 gram (g) = 1.0 g = 1000 mg |
| 1 kilogram (kg) = 1000.0 g |
| The Metric System of Liquid Measure |
| 1 milliliter (mL) = 0.001 L |
| 1 liter (L) = 1000 mL |
| The Avoirdupois System of Weights |
| 437.5 grains (gr) = 1 ounce (oz) |
| 16 oz = 1 pound (lb) = 7000 gr |
| Apothecaries’ System of Weights |
| 20 gr = 1 scruple |
| 3 scruples (ε) = 1 dram = 60 gr |
| 8 drams = 1 oz = 480 gr |
| 12 oz = 1 lb = 5760 gr |
| Apothecaries’ System of Liquid Measures (U.S. Wine Measure) |
| 60 minims = 1 fluid dram |
| 8 fluid drams = 1 fluid ounce (fl oz) |
| 16 fl oz = 1 pint |
| 8 pints = 1 gallon (cong.) |
Remarks:
The avoirdupois system of weights is used in buying and selling in commerce. This includes drugs.
The apothecaries’ system is used only for writing, compounding, and dispensing prescriptions.
The grain is identical in both the avoirdupois and apothecaries’ systems, but the ounce and pound are not.
One minim does not weigh 1 grain, and 1 fluid ounce does not weigh 1 ounce, and 1 pint does not measure 1 pound.
The scruple and apothecaries’ pound may be disregarded insofar as they are seldom used. When pound is used, it usually means an avoirdupois pound. When ounce is used, it usually means an apothecaries’ ounce.
∗ See also Jag’s Apothecary at http://www.ourworld.compuserve.com/homepages/jbaluri/home.HTM
Table 2 Equivalents (Approximate)
| 1 grain (gr) | 64.8 milligram (mg) | 60 mg |
| 1 ounce (oz) | 28.35 gram (g) | 30 g |
| 1 pound (lb) | 453.6 g | 454 g |
| 1 dram (60 gr) | 3.9 g | 4 g |
| 1 apothecary ounce (480 gr) | 31.1 g | 30 g |
| 1 minim | 0.06 (mL) milliliter | 0.06 mL |
| 1 fluid dram | 3.7 mL | 4 mL |
| 1 fluid ounce | 29.573 mL | 30 mL |
| 1 pint | 473.1 mL | 480 or 500 mL |
| 1 gallon | 3785.4 mL | 4000 mL |
| 1 mg |  gr |
 or  gr |
| 1 g | 15,432 gr | 15 gr |
| 1 kilogram (kg) | 2.2 pounds (lb) | |
| 1 gallon (water) | 8.337 lb (8 lb approx.) | 3.8 kg (approx.) |
| 1 gallon occupies 231 cubic inches | ||
| 1 mL | 1.000027 cubic centimeters | |
| 1 pint | 473 mL | 500 mL |
| 1 quart | 946 mL | 1000 mL |
| 1 drop | 0.06 mL | 1 minim |
| 1 dessertspoonful | 8 mL | |
| 1 teaspoonful (tsp) | 5 mL | |
| 1 tablespoonful (Tb) | 15 mL |
Table 4 Dry Weight and Volume Conversions
| 1 pound (lb) | 453.6 grams (g) |
| 1 gram (g) | 0.0022 pound (lb) |
| 1 gram (g) | 1000 milligrams (mg) |
| 1 gram (g) | 1,000,000 micrograms (μg) |
| 1 kilogram (kg) | 1000 grams (g) |
| 1 kilogram (kg) | 2205 pounds (lb) |
| 1 milligram (mg) | 0.001 gram (g) |
| 1 milligram (mg) | 1000 micrograms (μg) |
| 1 microgram (μg) | 0.001 milligram (mg) |
| 1 microgram per gram (μg/g) | 1 part per million (ppm) |
| 1 part per million (ppm) | 0.454 milligram/pound (mg/lb) |
| 1 part per million (ppm) | 0.907 gram per ton (g/T) |
| 1 liter (L) | 1000 milliliter (mL) |
| 1 milliliter (mL) | 1000 microliter (μL or lambda) |
| Abbreviation | English Translation |
|---|---|
| ac | before meals |
| AD | right ear |
| ad lib | as desired |
| AS | left ear |
| AU | both ears |
| bid | twice a day (every 12 hours) |
| Ċ | with |
| cap | capsule |
| d/c | discontinue |
| ft | make |
| h | hour |
| hs | at bedtime |
| m | mix |
| OD | right eye |
| OS | left eye |
| OU | both eyes |
| pc | after meals |
| po | by mouth |
| PR | rectally |
| PRN | as needed |
| pulv | powder |
| PV | vaginally |
| qam | every morning |
| qd | every day |
| QD (SID) | once a day |
| QH | every hour |
| qid | four times a day (every 6 hours) |
| qpm | every evening |
| qod | every other day |
| qs | as much as needed |
| Rx | recipe, Latin for “take thou” |
| Š | without |
| sig | directions, Latin for “to label” |
| SL | sublingual |
| SOL | solution |
| ss | one half |
| stat | now, immediately |
| supp | suppository |
| tab | tablet |
| tid | three times a day (every 8 hours) |
| ud | as directed |
| ung | ointment |
Table 6 Common Units and Conversion Factors
| Common Units of Measure | |
| Unit | Abbreviation |
| Concentration of solutions | |
| grams per deciliter | g/dL∗ |
| grams per liter | g/L |
| international units per liter | IU/L |
| micrograms per deciliter | μg/dL |
| micromoles per liter | μmol/L |
| microunits per milliliter | μU/mL |
| milliequivalents per liter | mEq/L |
| milligrams per deciliter | mg/dL |
| millimoles per kilogram | mmol/kg |
| millimoles per liter | mmol/L |
| milliosmoles per kilogram | mOsm/kg |
| parts per million | ppm |
| percent | g/dL |
| units per liter | U/L |
| Distance | |
| centimeter | cm |
| meter squared | m{2} |
| millimeter | mm |
| Fluids | |
| deciliter (102 mL) | dL |
| liter (103 mL) | L |
| microliter (10-6) | μL |
| milliliter (1 mL or 10-3 L) | mL |
| Pressure | |
| centimeters of water | cm H2O |
| millimeters of mercury | mm Hg |
| Time | |
| every | q |
| hour | hr |
| minute | min |
| month | mo |
| second | sec |
| week | wk |
| year | yr |
| Weights | |
| grain (1 gr = 65 mg) | gr |
| gram (1 g or 10-3 kg) | g |
| kilogram (10-3 g) | kg |
| microgram (10-6 g) | μg |
| milligram (10-3 g) | mg |
| nanogram (10-9 g) | ng |
| pictogram (10-12 g) | pg |
| Common Conversions | |
| Volume or Weight | Equivalent |
| 1 dram | 3.9 grams |
| 1 drop (gt) | 0.06 milliliter |
| 15 drops | 1 milliliter (1 cc) |
| 1 fluid dram | 3.7 milliliters |
| 1 glass | 240 milliliters (8 ounces) |
| 1 grain | 0.065 gram or 65 milligrams |
| 1 gram | 15.43 grains |
| 1 kilogram | 2.20 pounds (avoirdupois) |
| 1 kilogram | 2.65 pounds (Troy) |
| 1 liter | 1.06 quarts |
| 1 liter | 33.80 fluid ounces |
| 1 measuring cup | 240 milliliters (½ pint) |
| 2 measuring cups | 500 milliliters (1 pint) |
| 1 milligram | grain |
| 1 milliliter | 16.23 minims |
| 1 minim | 0.062 milliliter |
| 1 ounce | 31.1 grams |
| 1 ounce | 30 milliliters or 28.35 grams |
| 1 pint | 473.2 milliliters |
| 1 quart | 946.4 milliliters |
| 1 tablespoon | 15 milliliters |
| 2 tablespoons | 30 milliliters |
| 1 teacup | 180 milliliters (6 ounces) |
| 1 teaspoon | 5 milliliters |
| 1 unit (e.g., penicillin) | 0.000625 mg |
| Temperature Conversions |
| °Celcius to °Fahrenheit: (°C) (9/5) + 32° |
| °Fahrenheit to °Celsius: (°F-32°) (5/9) |