Recommendation for Manufacturers, Regulators, and Standards Setters to Promote the Safe Use of Modifiers in Prescription Drug Proprietary (Brand) Names

These recommendations apply to manufacturers and regulators involved in the production of medication.

Numerous medication errors associated with the use of modifiers in drug proprietary names have been reported through various reporting programs including the Food and Drug Administration (FDA) MedWatch Reporting Program and the ISMP National Medication Errors Reporting Program (ISMP MERP). 

Factors that contribute to medication errors associated with the use of modifiers in drug proprietary names include:

  1. Confusion resulting from the introduction of a new dosage formulation whose name and strength overlap with an existing drug product's name and or strength (e.g., Drug Name 120 mg vs. Drug Name ER 120 mg).
  2. Knowledge deficit with respect to the introduction of a modified-release product. Thus, prescriptions are written with:
    1. Incorrect dosing interval
    2. Incorrect dosing frequency
    3. Incorrect or non-existent modifier
    4. Omission of a modifier
    5. Incorrect spelling of the modifier
    6. Using the modifier alone rather than the complete drug name including the modifier
  3. Various extended-release modifiers and terms used to describe the same dosing frequency or release rate.
  4. Lack of uniformity and proliferation of different modifiers resulting in confusion in identifying the correct drug product.
  5. Modifiers such as LA, CR, CD, XL and SR having no standard interpretation that would give a clear meaning to indicate release properties or dosing frequency. 
    1. In addition, USP General Chapter <1151> Pharmaceutical Dosage Forms defines two categories of modified-release formulations: delayed and extended release. 
    2. Delayed release denotes a formulation that has a coating to delay release of the drug until the product has passed through the stomach. 
    3. Extended release denotes any formulation designed to deliver the dose over a longer interval (e.g., 12 hours, 24 hours) than what is seen in immediate release products.

The Council recommends the following:

  1. Manufacturers, when developing a modifier to be included in a drug proprietary name, should follow the recommendations contained in the FDA Guidance for Industry titled Best Practices in Developing Proprietary Names for Human Prescription Drug Products (
  2. FDA and the pharmaceutical industry should evaluate proposed drug proprietary names, including those that contain modifiers, to determine the potential for errors that could occur in any phase of the medication use process. This process should be done before these medications are approved for marketing and should include testing with the product’s intended audiences such as healthcare practitioners and consumers. 
  3. FDA and the pharmaceutical industry should ensure that product labeling (i.e., Prescribing Information or package insert) clearly indicates the modifier’s intended meaning and associated dosing information.
  4. The pharmaceutical industry should work with key stakeholders to develop and implement an efficient and effective approach for disseminating and communicating critical information to practitioners when a new modifier is introduced.
  5. USP, FDA, and the pharmaceutical industry should collaborate to review the safe use of drug proprietary and/or generic name modifiers, evaluate the advantages of standardizing the use of proprietary name modifiers, and address identified safety risks to standardize and define the meaning of modifiers for prescription and nonprescription drugs.
  6. USP should evaluate the terms immediate release, extended release and delayed release as they apply to marketed products and, through public comment, solicit feedback about the need for additional, more precise definitions and ways products could be differentiated for practitioners through naming and labeling.
  7. Regulators, standards-setters, and the pharmaceutical industry should encourage practitioners and consumers to report actual and potential medication errors associated with drug proprietary name modifiers.
  8. Practitioners should proactively employ processes to evaluate drug products that contain modifiers in the proprietary name to determine the potential for errors that could occur in any phase of the medication use process. This evaluation should be completed before these drug products are added to an organization's inventory or formulary.
  9. Whether in written orders, verbal orders, or electronic prescribing, prescribers should always indicate the complete proprietary and/or generic name, including the modifier when ordering such medications.
  10. Pharmacists should call prescribers to clarify prescriptions where the presence or absence of a modifier fails to agree with the prescribed dosing schedule.
  11. Practitioners should proactively educate patients about the use and meaning of drug proprietary name modifiers and how to properly use the medication since modifiers may impart meaning that impacts dosage and administration or other aspects of use and in order to reduce medication errors.

1 A suffix or modifier is a portion of the proprietary name. Some proprietary drug names are constructed of a root name and added word(s) or other components that are referred to as the suffix or modifier portion of the proprietary drug name. 

Actions/Decisions are those of the Council as a whole and may not reflect the views/positions of individual member organizations.