Apothecaries’ system

The apothecaries system uses whole numbers and fractions. Decimals are not used in this system. The whole numbers are written as lowercase Roman numerals, for example, x instead of 10, or v instead of 5. 

There are three systems of measurement of drug dosages die metric system, the apothecaries system, and household measurements. The metric system is die most commonly used system of measurement in medicine A physician may prescribe a drug dosage in die apotiiecaries system, but for die most part this ancient system of measurements is only occasionally used. The household system is rarely used in a hospital setting but may be used to measure drug dosses in the home... 

When setting up tiie proportion, the apothecaries system was written in Arabic numbers instead of Roman numerals, and their order was reversed (1 gr instead of gr i) so that all numbers and abbreviations are uniform in presentation. 

Because decimals are not used in the apothecaries system, this decimal answer must be converted to a fraction 0.005 is 5/1000, which, when reduced to its lowest terms, is 1/200. The final answer is now 0.3 mg = gr 1/200. 

Under certain circumstances, it may be necessary to compute an oral drug dosage because the dosage ordered by the physician may not be available, or the dosage may have been written in the apothecaries system and the drug or container label is in the metric system. 

Even if die physician s order was written in the apothecaries system, die drug container most likely would be labeled in die metric system. A conversion of apothecaries to metric will now be necessary because the drug label is written in die metric system. 

The basic unit for weight is grain (gr) and that of volume is minim (m). Unlike the metric units, the amount is expressed in Roman numerals after the apothecaries symbol. For example, V2 grain is expressed as gr ss but not V2 gr. Twenty minims is expressed as m xx. Sometimes physicians also use Arabic numerals in the apothecary system. For example 12 ounces can be written as l XII or 4 ounces as 4 l. Tables 2.4 and 2.5 show the relationships... 

Apothecary system. Use the metric system exclusively. Although you may have learned about the apothecary system and its grains, drams, minims, and ounces, it is very inaccurate. For example, symbols for dram have been misread as 3, and minim has been misread as 55. Orders for phenobarbi-tal 0.5 gr (30 mg) have been mistaken as 0.5 gram... 

Medication is measured using the metric system and the apothecaries system. The metric system is used to measure medication in a healthcare facility and used when prescribing and recording the medication in the patient s chart. The apothecaries (household) system is used by patients who self-administer medication. 

The metric system uses grams to measure weight and liters to measure volume, as shown in Table 7.1. Prefixes are used to indicate the value (Table 7.2). The apothecaries system uses ounces and pounds for weight and teaspoon, and tablespoon to measure volume. Table 7.3 contains conversion factors for the apothecaries system and metric system. 

TABLE 7.3 Conversion Factors for the Apothecaries System and Metric System... 

Converting Metric Units to Apothecaries System Units... 

Patients use the apothecaries system to measure medication when they self-medicate however, the medication may be delivered in metric units. Therefore, the healthcare provider must convert the prescribed dose from metric units to units of the apothecaries system. Use factors in Table 7.3 to convert values. The most common conversions are milliliters to teaspoons, tablespoons, or cups. A cup is measured in ounces. Another common conversion is pounds to kilograms. 

Several years ago, pharmacists used the Apothecary System of Measurement. In this system, 1 scmple is equal to 20 grains (gr). There are 480 gr in 1 oz, and in this system, there are 373 g in 12 oz. How many scruples would be in 695 g ... 

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