Considerations for a logical approach to medication prescribing

Introduction

The right to prescribe is accompanied by a tremendous responsibility to safeguard patient safety and quality of care, as well as accountability to various regulators. All 50 states, the District of Columbia, uniformed services, and all U.S. territories, except Puerto Rico, permit delegated prescribing of various drugs and medical devices by physician assistants (PA). With this privilege comes the responsibility of the PA to possess the foundational knowledge of medications they prescribe. Of equal importance, the PA needs to collaborate with the patient and family to determine the best medication therapy plan for optimal outcomes and also ensure patient safety and medication efficacy. To support optimal prescribing, this chapter offers regulations of prescribing, key information about controlled substances, guidance for evidence-based decision making, highlights of scientific factors related to medications, tips about safe and effective prescribing for special populations, challenges commonly faced by patients attempting to adhere to prescribed therapies, the rationale for interprofessional collaboration, and prescribing quandaries.

Regulation of prescription writing

Prescriptive authority for PAs has been expanding, with the scope ultimately dictated by individual state laws. A prescription is required for drugs that are considered potentially harmful if not used under the supervision of a licensed health care practitioner. Rules and regulations regarding defining and prescribing these drugs are dictated by both federal (i.e., U.S. Food and Drug Administration [FDA], Drug Enforcement Agency [DEA]) and state governing bodies (i.e., boards of pharmacy). The DEA is responsible for enforcement of the Comprehensive Drug Abuse, Prevention, and Control Act of 1970 and requires every PA to register with the agency if prescribing controlled substances.

The establishment and management of the five schedules of controlled substances is also a DEA responsibility, although states can legislate a more restrictive schedule. An example of a DEA Schedule I controlled substance is heroin, and a Schedule V example is pregabalin, with morphine, anabolic steroids, and lorazepam representative of Schedules II, III, and IV, respectively. The federal government does not recognize Schedule I controlled substances as having a medicinal use. Specific regulations exist regarding each class of scheduled drugs in regard to their prescribing and oversight and should be considered in the prescription process. Among these restrictions are often limits on the quantity supplied, refills prescribed, and time limit for a prescription to remain valid ( Table 13.1 ). The DEA and each State Board of Pharmacy websites provide a list of the schedule status for controlled substances.

Approach to prescription writing

The use of electronic medical records (EMR) has changed the approach to prescription writing, including the prescription writing for controlled substances. Adoption of electronic prescribing of nonscheduled prescriptions occurred early and as of 2016, all 50 U.S. states and Guam legally allow electronic prescribing of most controlled substances. Since then, many states have enacted, or are in the process of enacting, legislation requiring Schedule II drug prescriptions transferred electronically (Electronic Prescriptions for Controlled Substances [EPCS]) as a response to the opioid epidemic. In addition, 49 states, the District of Columbia, and the U.S. territories Guam and Puerto Rico have an operational prescription drug monitoring program (PDMP). Several states mandate that the PA before prescribing, and the pharmacist before dispensing, review the patient’s record on the PDMP. This program registers within the state database the controlled substance prescriptions picked up by the patient. The prescriber can view the controlled substance name, quantity, prescriber, and the pharmacy where it was filled/dispensed for their patient. This process exposes duplicate medications written by a number of prescribers and the use of different pharmacies, permitting the prescriber or pharmacist to have a frank conversation with the patient.

Electronic prescribing has eased the burden of writing prescriptions by hand, including all the components of a legal prescription: the prescriber’s information and DEA number, patient name, address, date, drug name, strength, dosage form, quantity, and route of administration with directions, along with refills and the signature of the prescriber. The EMR populates the information, the patient demographics, date, and possibly allergies, weight, and insurance information, improving the communication between the prescriber and pharmacist. Although the EMR prescribing process does eliminate illegible handwriting, it has led to a new set of issues, such that the rate of medication errors remains unchanged.

Potential causes for these errors include the use of drop-down menus for drug selection, drug strength, formulation, and auto populated directions. Another cause of error involves selecting the wrong directions from common preformed “Sigs,” which is the abbreviation for the Latin word signetur meaning “let it be labeled.” An example of a preformed “Sig” is the sig text string “T1T po BID prn HA” interpreted by the pharmacist as “Take 1 tablet by mouth two times a day as needed for headache.” A final error can occur when entering patient directions freehand. As a prescriber, it is important to carefully review all prescriptions before submitting them to the pharmacy. Another way to help prevent prescribing and dispensing errors is to connect the prescribed drug with the disease being treated. This should occur within the EMR and by adding the indication for the medication at the end of administration instructions when generating the prescription (e.g., the directions for antihypertensive medication could say: Take 1 tablet by mouth every morning for high blood pressure).

In the hospital, the addition of computerized physician order entry (CPOE) simplifies the process when writing inpatient prescriptions. The process allows providers to place orders into a computer system directly into the chart of a patient, bypassing the need for many of the components of a traditional prescription. These orders transfer to a pharmacist for verification of accuracy and appropriateness before dispensing. Whether using EMR or CPOE entry, avoid alert fatigue by clicking through the pop-up message boxes associated with a drug. These boxes alert the PA to drug-drug, drug-disease, drug-age, and drug-food interactions and deserve scrutiny.

This case continues through the chapter illustrating additional concepts related to medication prescribing.

Effective prescribing

PAs have access to numerous books, online references, and application technology. Still, a systematic approach in selecting medications is necessary and important to both maximize the effectiveness of the medication and minimize the harm to the patient.

A 1995 landmark study in the United States developed a model to estimate the associated costs of drug-related morbidity and mortality in the ambulatory setting. The model estimated a drug-related cost of $76.6 billion, with patient hospitalizations noted as the largest expense. An updated cost calculation published in 2018 estimated the drug-related cost increased to $528.4 billion in 2016 U.S. dollars. The average cost of an individual experiencing a treatment failure (TF), a new medical problem (NMP), or both TF and NMP after initial prescription use was $2481. For the United States in 2018, the Kaiser Family Foundation reported that approximately 3.79 billion prescriptions were written, averaging 11.6 prescriptions per capita and costing nearly $379 billion. With an ever-growing selection of medications available to prescribers, the choice among agents can be daunting. Each prescription must take legal, evidence-based, pharmacologic, and patient-specific factors into consideration to minimize drug-related morbidity and mortality.

Evidence-based approach to medical decision making

The World Health Organization created a guide to good prescribing, which suggests that all drug therapy decisions should consider efficacy, safety, cost, and sustainability. The process of rational prescribing is further broken down into six steps. These steps are detailed in the quick reference Table 13.2 and will be highlighted in the following sections.

When a patient presents with a complaint, the PA spends time defining the patient’s problem and goal of any treatment (Step 1 and 2). A factor often overlooked is if a previously prescribed drug is the cause of the patient complaint, supporting inclusion of drug-related problems as part of the differential diagnosis. A troublesome side effect, dosing schedule, or prohibitive cost could be the reason for an adherence issue. In collaboration, a patient’s concerns, expectations, and any input they wish for you to consider should be a part of a treatment decision.

Steps 3 and 4 involve assessing if the preferred treatment is suitable for the patient. The use of evidence-based literature along with searchable drug information databases is helpful. Considerations should include what the drug of choice is in this disease state. Is the drug of choice safe and effective for this patient (i.e., no allergies or contraindications to use)? Does the literature supporting efficacy of this medication in a large population correlate to my patient population as well? This is referred to as a risk–benefit analysis during which you as the prescriber must decide if the benefit of the medication regimen far outweighs any risk of using this medication regimen for your patient (e.g., cost, adverse effects, morbidity, mortality).

Step 5 is the communication piece between the PA and patient on treatment options. Moving through this step too quickly may prevent the patient’s understanding of the benefit of the drug, leading to medication nonadherence by either never filling the prescription or not taking the medication as prescribed. It is concerning that over 30% of new prescriptions never reach the pharmacy for filling. In 2016, poor medication adherence claimed three times more lives than those attributed to the opioid epidemic. Drug costs, copays, and perceived value are important patient considerations.

Step 6 is your plan for monitoring the treatment you prescribed. Both the patient and the PA have a responsibility to monitor medications for therapeutic endpoints or adverse reactions. The patient needs to report new concerns, as well as persisting or worsening symptoms before stopping a drug. The PA needs to adjust the treatment plan expeditiously and provide criteria for when to seek emergency care.

Pharmacology and pharmacotherapy

The Merriam-Webster dictionary defines pharmacotherapy as the treatment of disease and pharmacology as the science of drugs, including their origin, composition, pharmacokinetics, therapeutic use, and toxicology. Both are required knowledge for the PA. Pharmacology includes the two main topics of pharmacodynamics and pharmacokinetics. Pharmacodynamics can be easily described as the effect of a drug on the body and pharmacokinetics as the effect of the body on a drug. Recognizing basic pharmacodynamics and pharmacokinetic principles is a key concept needed for pharmacotherapy, which includes medication prescribing, monitoring, and management.