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