Dispensing Pharmacy Textbook Pdf

[Ogier Dudley]

Utilizingpharmacy calculations to administer therapeutics to patients correctly is vital to patient treatment. Health care professionals must dispense drugs in the accurate concentrations, calculate correct doses, and compound and prepare medications accurately to ensure that each particular drug is being administered correctly.

Dose refers to the amount of medication taken at a specific time, whereas the dosage of the drug refers to the administration of a frequency, amount, and the number of doses taken over a particular period of time.

The relationship between concentration and volume is inversely proportional. (See Figure 1 for a schematic of the inverse relationship between percent of concentration or ratio strength (decreases), and the total quantity of product (increases)).

It is important to note that when two solutions have equal osmotic pressure and salt concentration, they are said to be isotonic. Normal saline has a concentration of 0.90% w/v of NaCl in sterile water and therefore is an isotonic crystalloid.[5]

Additionally, pharmacy calculations require the knowledge of commonly used units; certain medications are dispensed in metric system units such as mg or mL, whereas others may be dispensed in other measurement systems. Vitamin D, for instance, is administered in International Units.[7]

Drugs may be administered through various routes of administration, oral, IV, IM, parenteral, etc.; these factors must be accounted for when computing calculations and consistency when converting units across different measurement systems is important in maintaining accuracy in pharmacy calculations. This issue also impacts patient care as patients may use the household and avoirdupois systems when using their medications (teaspoons and tablespoons), although the medication was dispensed in mL. It is important to know units within each system (such as 1 pound = 16 ounces). quantity, conversions are required between the US Customary System and the metric unit system.[8] Some commonly used conversions are:

Roman numerals are often used on prescriptions as they are challenging to alter, whereas decimals are also used elsewhere in pharmacy practices. Measurements requiring decimals are usually converted into fractions; thus, familiarity with converting measurements between various systems and a foundation in basic arithmetics in terms of fractions, ratios, proportions, and percent is necessary to perform pharmacy calculations.

The aliquot method consists of measuring out a small amount of drug, by diluting a larger amount. Aliquoting plays an essential role as a technique to separate a larger sample into smaller parts; it is also equally as important in temperature sensitivity of drugs.[9]

Lastly, stock solutions exist to dispense medications to patients. However, certain patients require different concentrations of drugs, and the Alliqation method exists to calculate and dispense correction concentrations of active ingredients for patients. (See Figure 2 for a schematic of the Alligation method).[10]

It may also be important to account for patients' weight when calculating the correct dose for certain drugs. The body surface area represents the patient's height and weight. In certain patient populations, specific drugs may be dosed based on BSA depending on drug properties. The average adult has a BSA of 1.73 m^2. The equation for BSA may be calculated as follows:

In regards to toxicity, understanding properties of certain drugs is important in order to eliminate them effectively. For acidic drugs: pH = pKa + log [A-]/[AH] and for basic drugs: pH = pKa + log[B]/[BH+].[15]

In addition to pharmacy calculations, other factors in pharmacology must also be a consideration. For instance, bioavailability is the amount of drug from the administered dose that reaches the systemic circulation and should be taken into account. Different routes of administrations can impact drug bioavailability.

It is essential to understand the relationship between pharmacokinetics and pharmacodynamics as these factors influence the drug effect and metabolism. (See Figure 3 for a schematic of the relationship between pharmacokinetics and pharmacodynamics.)

Pharmacodynamics is the study of drug effects and their metabolism of action.[16] Understanding potency of a drug (the amount of medication required to a given intensity of effect) and efficacy of the drug (maximum response achievable), and whether the drug has agonist or antagonist properties. Pharmacokinetics is the study of the time required for the drug to be absorbed, distributed, metabolized, and eliminated (ADME).[16]

Accurate pharmacy calculations are not only necessary for dispensing, dosing, and adequately medicating patients but also a vital component of pharmacological therapy, effect, and, ultimately, patient care. The interprofessional health care team must work together to determine and administer adequate pharmacological treatment to patients. Specifically, differing patient populations may have varying needs. Liver and kidney dysfunction can alter the metabolism of a drug, as can age.[17] Beers criteria are often used to determine which drugs to avoid in the elderly patient.[18] Thus, the accuracy of pharmacy calculations remains an important component of pharmacologic therapy and patient care.

Pharmacists are an important part of your health care team and offer a variety of services. Over 409,000 people have been treated for minor ailments or gotten free contraceptives from pharmacists since June 2023. Book an appointment or walk-in to a pharmacy to find out more.

Pharmacists are licensed health care professionals. They are bound by the same confidentiality rules as a family doctor or nurse practitioner. Your health information and conversations are private and confidential.

Pharmacies charge different amounts for drugs and for dispensing them. You can compare prices and services before you fill a prescription. If you need help paying for medications and pharmacy services, consider registering for Fair PharmaCare.

Pharmacists can start you on a free 12-week course of nicotine patches, lozenges or gum. They can also prescribe the oral medications varenicline or bupropion, which you may have to pay for some or all of, depending on your PharmaCare coverage.

Prescriptions are valid for up to 2 years from the date they were written. If you have just run out of medication and your prescription was written more than 2 years ago, your pharmacist may be able to provide an emergency supply until you can get a new prescription from a doctor or other prescriber.

If you are taking five or more medications, you may be eligible to ask your pharmacist for a medication review. A pharmacist will meet with you to create a list of all your medications and other health products, and discuss how best to take them.

The B.C. Public Service acknowledges the territories of First Nations around B.C. and is grateful to carry out our work on these lands. We acknowledge the rights, interests, priorities, and concerns of all Indigenous Peoples - First Nations, Mtis, and Inuit - respecting and acknowledging their distinct cultures, histories, rights, laws, and governments.

CURRENT ISSUEJoin a patient-centered community of Medically Integrated Oncology ProfessionalsNCODA is an association that aims to create a global network of compassionate, patient-centered professionals in the field of oncology. With membership in all 50 states and seven countries, NCODA is dedicated to supporting all cancer care professionals in the medically-integrated dispensing of cancer therapies. By doing so, they strive to ensure quality patient care and achieve more positive outcomes for cancer patients worldwide.

Ken Komorny is the Vice President and Chief Pharmacy Officer, for Moffitt Cancer Center. Ken has been with Moffitt since 2018, overseeing all pharmacy services, including multiple hospitals and hospital-based outpatient infusion centers, specialty pharmacy, clinical services, and investigational drug services. He has more than 25 years of experience in pharmacy leadership. Among his accomplishments at Moffitt, Ken has overseen the remodeling of all the IV center pharmacies for full compliance with USP 797 and 800 to better protect patients and pharmacists, development of the best-in-class specialty pharmacy, optimization of clinical services, novel project development in the investigational drug service, and significant improvements in the financial health of the pharmacy department.

Ken also actively advocates for safe medication practices that have been challenged by insurance policy changes. Through the National Comprehensive Cancer Network (NCCN) and other groups he has written white papers on operationalizing and financial sustainability on biosimilar medications. He was part of a workgroup with the Board of Pharmacy on white and brown bagging, and then testified at the Florida Senate on white bagging and site of care practices that led to passing of a PBM reform bill (Senate Bill 1550), which mandated that PBMs provide contracts to centers such as Moffitt Cancer Center. Ken has given more than a dozen presentations locally, regionally, and nationally, including in Washington, D.C., with groups such as the Food and Drug Administration.

Ken has a Doctor and a Bachelor of Science in pharmacy and has been Board Certified in Pharmacotherapy since 1999. He is or has been a member, committee member, and officer of various organizations (Hematology/Oncology Pharmacy Association, Florida Society of Clinical Oncology, Ohio College of Clinical Pharmacy, American Society of Health-System Pharmacists, and Florida Society of Health-System Pharmacists. Ken leads various committees with the National Comprehensive Cancer Network, Alliance of Dedicated Cancer Centers, Premier, and the Florida Society of Health-System Pharmacists. He has been faculty in the Pharmacy Leadership Academy of the American Society of Health-System Pharmacists and gives leadership lectures.

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