Issue link: https://www.e-digitaleditions.com/i/1520859
24 Pharmaceutical Technology ® Trends in Manufacturing eBook May 2024 PharmTech.com Compounding Content in this discussion ref lects academic teach- ing, personal experiences in multiple organizations, and published accounts of adverse events. Textbooks (1–9) and academic education provide theory. Appli- cation in the workplace is much different—actual drugs, sick patients, medication orders in multiple formats, time pressures, information discrepancies, and workplace interruptions and distractions—all of which have potential for errors. Calculations errors may have significant ramifications: patients receive toxic overdoses or ineffective underdoses; healthcare practitioners suffer personal remorse (10); manage- ment is embarrassed (11); and organizations face legal consequences (12). Additional discussion on this topic including case studies is available under the same title at PharmTech. com (13). The calculations process in this discussion is focused on specific calculations activities separate from a comprehensive dosage form compounding process. Stage 1. Equation design Stage 1, equation design, comprises activities in ad- vance of actual calculations (i.e., thinking, planning, verifying information, estimating, setting up equa- tions, and initiating documentation). Stage 1 empha- sizes proactive thinking about the calculations to be performed. Calculations objective. Calculations for prepara- tion of a compounded dosage form must be clearly identified. Three questions are fundamental: 1. What is to be calculated? What is the desired final outcome of the calculations? Where are we going? 2. What information is known? What is given, what is relevant, what is not relevant? What is the medication order telling us? Excess informa- tion sometimes confuses identifying the calcu- lation objective. 3. What is unknown? What don't we know, what is missing, what is questionable and needs con- firmation, and how do we get this information? This is a tried-and-true process in problem solving, troubleshooting, investigations, and related activi- ties. It forces thorough and logical thinking. A plan to accomplish the calculations objective is needed. One cannot begin to set up equations without initiating logical and common-sense thought. Especially rel- evant in these activities are the associated units of measure for all values. Compile information. Concurrent with identifica- tion of the calculations objective is the collection of relevant information. Missing information must be obtained; questionable information must be inves- tigated. Pertinent information must be written; do not make assumptions or depend on memor y. Cor- rectly executed calculations using erroneous infor- mation may be fatal (14). Verbal information must be repeated and confirmed in writing. Misunderstand- ing due to language dialects may contribute to errors. The following must be critically addressed and inte- grated before initiating calculations: • Patient information. Patient data (age, weight, organ function, diagnosis) are basic; medication order consistency with diagnosis (e.g., metho- trexate dosage for cancer or rheumatoid arthri- tis?), sensitivities (lactose, alcohol), allergies (dyes, peanuts), other intolerances; religious preferences may restrict use of certain ingre- dients. What other drugs is the patient taking (drug interactions)? Multiple patients with iden- tical surnames are an obvious hazard. • Medication order. L ook-a l i ke sou nd-a l i ke (LASA) drugs (15), high-alert drugs (16–18), con- f used dr ugs (mor phine and hydromor phone) (19), abbrev iated dr ug na mes (HCT, HC, MS), and problematic unit symbols (units, mg, mcg, u) in medication orders must be scrutinized (20). Questionable routes of administration with as- sociated drug dosages (opioids, diltiazem, epi- nephrine) must be confirmed. Known problem sit uations (ca lcium phosphate dosage, intra- thecal administration, neonatal patients) may require additional verification. The Institute for Safe Medication Practice (ISMP) recommends er- ror-prevention strategies for high-alert drugs as a medication safety best practice (21). • Drug and dosage form. Problematic drug and dosage form issues should be highlighted to all involved personnel. Drug interactions must be evaluated. Drug stability, compatibility with ex- cipients, special drug administration require- ments (intravenous nitroglycerin), light protec- tion (nitroprusside), supply chain temperature control, etc. must be identified. Pertinent refer- ence information must be documented. Calculation estimate. After relevant information is known, the expected calculation should be esti- mated based on rounded values and common sense. Estimation forces proactive thought about calcula- tions. Compiled information must be integrated prior to estimation (e.g., unique patient information may affect usual dosage). What is a usual dose? What is a maximum dose? Will the calculated result unit be in kilograms, grams, milligrams, or micrograms? Will units be in mL, millimoles, or milliequivalents? A drug dosed in milligrams will not likely require kilogram drug amounts for compounding; small in- travenous additives (0.05 mL) cannot be measured with conventional equipment. The estimated value will later be utilized when the final actual calcula- tion is evaluated. Estimating future calculations re-