Definition/Introduction

Prescribing clinicians are often visited by patients looking for medications to remedy their chief complaint. Prescriptions are written for controlled and noncontrolled medication categories. There are 5 different levels of scheduling for controlled medications (I-V), with schedule I having the tightest controls and V being the least restrictive. For over-the-counter medications, prescriptions are not usually required. Some OTC medicines, based on their dosage limits or total days supply, mandate the prescription by the provider (ie, pseudoephedrine in dosage of more than 9 grams per 30 days). For all prescriptions, clinicians need to understand the mechanism and properties of the medication before prescribing, and the pharmacist must be aware of potential interactions the patient may have with their other medications. 

Controlled substances are drugs considered to have the highest misuse and use disorder potential and thus have the strictest regulation and prescription requirements on a federal and state level. To prescribe a controlled substance, a clinician must have a DEA (Drug Enforcement Administration) license. A pharmacy must also have a controlled substance license to fill a prescription. Schedule I medications (eg, heroin) are unable to be prescribed or filled by a pharmacist because they have no indicated medical use in the USA. Schedule II drugs are the highest level of misuse potential medications that a clinician may prescribe; these drugs traditionally were only allowed to be filled by paper prescription. However, they are now prescribable via electronic prescribing of controlled substances (EPCS). Schedule III-V medications may be prescribed by a clinician via traditional paper prescription, by a verbal order over the phone, or by using the EPCS system.[1][2]

The EPCS was implemented in 2010 by the DEA, which stated that clinicians might submit controlled substance prescriptions electronically and that pharmacies could dispense these electronic prescriptions. Using the EPCS from a clinician and pharmacy standpoint is voluntary, and each party may choose to use the system. However, some states, such as New York, make electronic prescribing mandatory, with certain exceptions. Practitioners may still write and sign prescriptions for schedule II-V medications; verbal orders are only permitted for schedule III-V medications. Implementing electronic prescribing has significantly reduced the number of medication errors from a prescription standpoint (legibility, dosage, frequency, etc.).[2][3]

For a pharmacist to dispense a controlled substance, the prescription must include specific information to be considered valid:

• Date of issue
• Patient's name and address
• Patient's date of birth
• Clinician name, address, DEA number
• Drug name
• Drug strength
• Dosage form
• Quantity prescribed
• Directions for use
• Number of refills
• Signature of prescriber

There are legal limits on the number of refills and the number dispensed with a prescription. For a schedule III-V drug, the maximum refills are 5, and the quantity limit is 90 days supply per allocation. Schedule II drugs have zero refills; the maximum amount dispensed is 30 days supply.[4]

The Institute of Safe Medicinal Practice (ISMP) publishes a List of Error-Prone Abbreviations, Symbols, and Dose Designations, which contains abbreviations, symbols, and dose designations that have been documented through the ISMP National Medication Errors Reporting Program (ISMP MERP) and have been interpreted wrong and involved in harmful or potentially harmful medication errors. These abbreviations, dose designations, and symbols should never be used by any clinicians or pharmacists for communication of prescriptions verbally, electronically, or in handwritten prescriptions. ISMP may be contacted at the address below for reporting any close calls, errors, or hazards by calling 800-FAIL-SAFE, the ISMP Web site (www.ismp.org), or via e-mail at ismpinfo@ismp.org.[5]

Issues of Concern

Controlled substances are prescribed by a variety of clinicians, including physicians, dentists, advanced practice providers, and podiatrists. The prescribing practitioner must possess authorization from the DEA and have practicing rights within the prescribed origin's given location.

If there is any confusion for the pharmacist as to the reason for a prescription, or there are any other questions for the provider, then the pharmacist should contact the provider directly. A 2017 study showed that of all medications requiring clarification, 74% were new prescriptions, and only 36% of those needing clarification were electronically prescribed. The most frequent reasons for the pharmacist to contact the prescriber were for prior authorization approvals and missing prescription information. The study found that telephone contact was the most efficient means to correct these miscommunications.[6] A pharmacist can call the prescriber for most omitted information in a prescription; some parts of prescription information cannot be added through calling (eg, patient name).

Pharmacists play a crucial role in helping to limit the fraud that may occur; examples of potentially fraudulent activity are:[4][2]

• Stealing a clinician's prescription pad
• Calling in medications pretending to be a clinician
• Altering a pre-existing prescription

It is important to remember that states may pass laws that alter how they govern the prescription requirements for different medications. An example of this is marijuana, which at a federal level is considered a Schedule I drug, whereas some states permit its medical use and distribution. Pharmacists and practitioners should know the legislation within their jurisdiction to provide appropriate patient care.[1]

However, state law is often more stringent than federal law. An example is drug monitoring systems for opioid prescriptions. Prescription drug monitoring programs are conducted state-by-state and are an electronic database of information on prescriptions filled within that state. The purpose of these monitoring programs is to limit drug abuse and addiction. Most states have a fully operating monitoring program.[7]

Clinical Significance

Partial filling of a prescription for a schedule II medication is only allowed if the pharmacist cannot provide the patient with the total quantity prescribed; the pharmacist must note on the written prescription or the electronic record how many tablets or capsules were dispensed. According to the Controlled Substance Act, the completion of a partial dispensing of schedule II medications must occur within 72 hours of the initial allocation, after which the prescription is no longer valid for the remaining undispensed quantity. If this task cannot be completed, the pharmacist should contact the practitioner about obtaining a new medication.[4]

Partial filling for a schedule II may also occur for patients in long-term care facilities or a patient with a terminal illness so that the partial filling may be an individual dose; the pharmacist must document that the patient is terminally ill or in a long-term care placement before partially filling the medication. The remaining portion of the prescription should be filled within 60 days from the prescription date unless the prescription is terminated because the drug is no longer necessary.[1]

Schedule III-V medications can be partially filled within six months of the original prescription.[1]

A 2017 study found a significant reduction in prescription errors for patients discharged from emergency departments when medications were prescribed electronically versus handwritten. The specific findings were that electronic prescriptions demonstrated decreased incidence of missed dosages, inaccurate frequency of medication, incorrect dosage strength, and the overall ability to read the document (eg, some clinician's handwriting was illegible).[8]

Nursing, Allied Health, and Interprofessional Team Interventions

The healthcare team needs to work together to address safe and effective pharmacotherapy in their patients, especially with controlled substances. The healthcare team should schedule their patients for routine follow-up visits that include a history and physical exam to monitor for adverse drug effects and drug misuse. Monitoring for signs of drug misuse is a fundamental responsibility for the healthcare team because of the epidemic rates of drug misuse worldwide. Methods for monitoring drug abuse as well as drug diversion include assessment surveys, state prescription drug monitoring programs, urine screening, adherence checklists, motivational counseling, and dosage form counting, (eg, tablet counting). Pharmacists and other health care providers can prescribe and dispense naloxone for qualifying patients through standing orders to save lives.[9]

Nursing, Allied Health, and Interprofessional Team Monitoring

Prescribers and pharmacists must verify all essential elements of prescription writing and verification to dispense the correct medication. The Prescription Drug Monitoring Program (PDMP) constitutes a sophisticated electronic database that enables the accurate tracking and monitoring of prescriptions for controlled substances. Clinicians and pharmacists use this system to identify suspicious or unusual patterns in prescription drug use, which might indicate misuse or illegal activity. PDMP programs have been shown to prevent prescription drug misuse and overdose. According to CDC guidelines, the healthcare team must ensure that a new opioid prescription does not increase the risk of cumulative opioid overdose or dangerous medication combinations for the patient.[10][11]