Here are some important tips to remember when converting from one metric unit to another … [mg]-to-[grams], [liters]-to-[ml], [cm]-to-[mm], etc … 1) First thing to ask yourself is … “what is the relationship between the two different units? ” Here is an example of what I mean. If you are asked to convert 300mg into its equivalent value expressed in grams (g), you first need to determine how many of the smaller units are contained in one of the larger units … in this case we would use the fact that [1g] is equal to [1000mg], or stated another way, each 1-gram contains 1000mg.
2) Knowing the relationship between units in a conversion gives you a critical piece of info that you will need to solve the problem. This piece of info is called a RATIO. IMPORTANT NOTE: a RATIO can be inverted depending on what unit you are solving for. This is explained further in step-3 below. 3) The fact that one-gram equals 1000-mg can be expressed as a RATIO in either of the following two ways: [1g/1000mg] or [1000mg/1g]. You’ll see how valuable this ‘RATIO’ is in step-5 below where I will show you how to set-up this problem. 4) Using the numbers from above, here is what we know so far.
We have our original value of 300mg, and we know that there are 1000mg in each 1-gram (again, this is most useful if written as a ‘RATIO’ in either of the following two ways … [1000mg/g] or [1g/1000mg]). 5) Here’s the set-up – 300mg x 1g/1000mg = (300)(1)/1000 = 300/1000 = 0. 3g . Look closely at what just occurred … we multiplied 300mg x 1g, then divided this number by 1000mg. DON’T MISS THIS PART!!! …the [mg]units cancel each other out, leaving our final answer in grams (g), which is precisely what the question asked of us (see the color illustration of this problem below). 300mg x 1 g = (300mg)(1g) = 300 = 0. 3g 1000mg 1000mg 1000.
Let’s do another one! This time let’s go the opposite direction, converting a value originally expressed in a larger unit into the same value expressed in a smaller unit. Here we go … “1. 5-liters (L) is equal to how many milliliters (ml)? ” 1) Remember what we do first? Determine the relationship between the two different units that are involved, in this case liters (L) and milliliters (ml). Knowing this relationship will give us the all-important ‘RATIO’ that we can use to complete the conversion! 2) Since each 1-liter (L) contains 1000-milliliters (ml) our RATIO could be written as either [1L/1000ml] or as [1000ml/1L].
Now, on to step-3 where we set-up and solve the problem. 3) 1. 5-L x 1000ml/1L = (1. 5)(1000)/1 = 1500ml. This time the [L] units cancelled each other out, leaving our final answer in [ml] as requested! As with the first conversion that we did, below I have provided a colorful illustration of how the problem looks at each step along the way … 1. 5L x 1000ml = (1. 5L)(1000ml) = 1500 = 1500ml 1L 1L 1 for an ALTERNATIVE METHOD of METRIC CONVERSION… refer to pages 131 – 137 for an explanation of simple tool known as the “Sliding Mnemonic” for converting within the Metric system.
This Mnemonic device is a tool that shows how many places to move the decimal point when converting from metric unit to another, which can be a quick way to accomplish the task. Give it a try …it may end up being your ‘preferred’ method! —DOSAGE FORMS There are many different types of oral drug dosage forms, from capsules and tablets, to quickly dissolving tablets used both on and under the tongue, to various types of syrups and solutions. It’s also important to understand the differences between the wide range of solid oral dosage forms which are currently available (tablets, capsules, etc).
Note what makes these different from each other, what makes them unique. How does an Enteric-Coated tablet compare to a Sustained-Release tablet? How does a Troche compare to a Sublinqual tablet? What is the purpose of a Buffered tablet? Are there advantages of a Tablet versus a Capsule? —MORE on TERMINOLOGY! Terminology is extremely important in the study of Pharmaceuticals. Each of the terms below have very specific definitions which are important to understand. These can be found in chapter-3 of your textbook between pages 48 and 54, including Table 3-1. Here is a partial list:
off-label use- a medication can be indicated and prescribed therapeutically for a condition that has not been studied by the manufacturer for FDA approval. official name-also generic name chemical name-of a drug identifies the exact chemical compound of a medication and its molecular structure. generic name-or nonproprietary name, also called the common name, is the one given a drug when a manufacturer first proposes it to the FDA for approval. The generic name is never capitalized, is easier to remember than the chemical name, and is not the property of the manufacturer.
Generic drugs are often used when prescribing in preference to proprietary drugs because they tend to cost less, have the lowest potential for errors, and identify the drug no matter what manufacturer. Trade, Brand, Proprietary name-all refer to a drug nameowned by a specific manufacturer and can be used only by the original manufacturer. The symbol ® follows a trade name, indicating that the nameis a registered trademark and is restricted to use by the owner of the name, usually the manufacturer that owns the patent. Trade names are designed to be easily remembered (e. g., Viagra, Claritin).
The first letter of a trade name is capitalized, and the name may suggest some special feature of the drug, such as Skelaxin, a skeletal muscle relaxant. Confusion is possible when trade names are used because names for entirely different compounds may be pronounced or spelled similarly. Legend drug- is the name for drugs sold only by prescription, such as meperidine (Demerol) and diazepam (Valium). So named, these drugs must bear the federally mandated warning or legend—“Caution: Federal law prohibits dispensing without a prescription”—thus the name legend drug.
OTC name-ibuprofen, Advil, Nuprin, Motrin IB (the last three are also proprietary names) do not require a prescription. Indication-a sign or piece of information that indicates something Contraindication-a situation in which a drug should not be used because it may be harmful. Drug nomenclature- refers to all the names by which a drug can be identified—all drugs have a chemical name, an official or a generic name, and a trade name, and may have an OTC name.
— “TEST YOUR KNOWLEDGE” — After a trip to see your doctor, would you be more likely to leave the office with a ‘Medication Order’ or a ‘Written Prescription’? Be prepared to explain your answer. — WRITING PRESCRIPTIONS Abbreviations are central to prescription writing and recording, therefore it is essential that you recognize and identify those most commonly seen. See how well you do on the following list: IM IV SL ac pc b. i. d. t. i. d. q. i. d. q4h DRUG INFORMATION.