What does a D stand for in a medical prescription? Decoding common abbreviations and risks

October 8, 2025 •

4 min read

According to the Institute for Safe Medication Practices (ISMP), numerous serious medication errors have been attributed to the use of abbreviations, including those involving the letter 'D'. As a result, many have been placed on 'Do Not Use' lists. Understanding what a D stands for in a medical prescription is critical for patient safety, as it can refer to instructions ranging from a specific dosage to discontinuing a medication entirely.

Quick Summary

The letter 'D' can represent several different meanings on a prescription, including instructions like 'discontinue' and 'every other day,' specific doses like 'dextrose 5% in water,' or a drug name. Due to potential confusion, many healthcare providers now avoid ambiguous 'D' abbreviations.

Key Points

Ambiguity of 'D': In medical prescriptions, the letter 'D' can have multiple, context-dependent meanings, including instructions, dosage, and specific drug formulations.
Common 'D' Meanings: Common meanings of abbreviations with 'D' include D/C for "discontinue," dieb. alt. for "every other day," and div. for "divide".
High-Risk Abbreviations: The abbreviations OD (once daily vs. right eye) and q.o.d. (every other day) are considered high-risk and are on 'Do Not Use' lists due to potential for dangerous confusion.
Pharmacist's Role: Pharmacists play a crucial role in verifying and translating prescription abbreviations, providing clear, spelled-out instructions on medication labels.
Ask Questions: Patients should always feel empowered to ask their healthcare provider or pharmacist clarifying questions about their prescription to ensure they understand the instructions completely.
Standardized Practices: The healthcare industry is moving toward standardized practices, such as electronic prescribing and using spelled-out words, to minimize the risk of medical errors from abbreviations.

The Diverse Meanings of the Letter “D”

On a medical prescription, a seemingly simple letter like 'D' is rarely straightforward. Its interpretation depends heavily on context, the letters it is paired with, and the standards of the prescribing institution. This is a primary reason why many healthcare providers are moving away from handwritten prescriptions and high-risk abbreviations. The ambiguity can lead to dangerous errors if not clarified. For a patient, understanding the potential meanings is the first step toward effective medication management and safe health practices.

Common Instructions and Formulations Involving “D”

One of the most common and important abbreviations involving 'D' is D/C, which stands for "discontinue" or "discharge". This is often noted when a patient is leaving the hospital or is instructed to stop taking a particular medication. Another key instruction is dieb. alt. (or diebus alternis), which means "every other day". You might also see div., short for divide, indicating that a tablet or capsule should be split. For intravenous medications, D5W is a very common notation, referring to a 5% dextrose in water solution. These are just a few examples that highlight the directive nature of 'D' when used in shorthand.

Potential for Error: Ambiguous Abbreviations

Some 'D' abbreviations are now on national 'Do Not Use' lists due to their high potential for misinterpretation. A prime example is OD (or o.d.), which has two very different meanings. In some contexts, it stands for once daily (from the Latin omni die). However, in ophthalmology, it means oculus dexter, or right eye. A pharmacist or technician misreading a prescription could instruct a patient to take eye drops orally or apply a pill to their eye, which could be extremely harmful. Similarly, q.o.d. (or QOD), which stands for every other day, can be easily confused with q.d. (every day) or q.i.d. (four times a day), leading to a patient receiving the wrong frequency of medication.

The Importance of Context and Patient Dialogue

For patients, deciphering these abbreviations is not a substitute for clear communication with their healthcare provider. When receiving a prescription, it is essential to ask clarifying questions to ensure you understand the dosage, frequency, and other instructions. Healthcare institutions and pharmacies are working to reduce these errors by using standardized, spelled-out instructions and electronic prescribing systems. The goal is to eliminate any chance of confusion arising from ambiguous abbreviations.

Dispense and Administering Abbreviations

Beyond frequency and discontinuation, 'D' appears in other instructions. For example, DAW means "dispense as written". This is an instruction for the pharmacist not to substitute a generic version of the drug. The root Latin term dosis, meaning "dose," can also appear in forms like D.d. for give dose or d.t.d. for give of such doses. All these examples illustrate the layered and complex nature of medical shorthand.

A Comparison of Common "D" Abbreviations


Abbreviation	Latin Origin (if applicable)	Meaning	Context	Risk of Error
D/C	N/A	Discontinue or discharge	Instruction to stop a medication or release a patient	Medium to High, potential for misunderstanding context.
dieb. alt.	`diebus alternis`	Every other day	Medication frequency	Low, but superseded by clear instructions.
div.	`dividere`	Divide	Split a tablet	Low, but could be forgotten by patient.
D5W	N/A	5% Dextrose in Water	Intravenous fluid	Low, commonly understood by medical staff.
DAW	N/A	Dispense as written	Prescribing instruction to pharmacist	Low, specific to pharmacy procedure.
OD / o.d.	`omni die` / `oculus dexter`	Once daily / Right eye	Medication frequency or administration location	HIGH, on 'Do Not Use' lists due to extreme ambiguity.
q.o.d.	`quaque die alternis`	Every other day	Medication frequency	HIGH, easily confused with `qd` or `qid`.
d., D.	`die` / `dosis`	Day / Dose	Infrequently used, context-dependent	High, ambiguity has led to use of more explicit terms.

Why Understanding Abbreviations Is Critical for Patient Safety

Deciphering medical prescriptions is a vital skill, not just for healthcare professionals but also for patients taking an active role in their own health. Errors stemming from misunderstood abbreviations can result in a patient taking the wrong medication, the wrong dose, or taking it on an incorrect schedule, all of which can have serious or fatal consequences. While pharmacies provide translated labels, understanding the source terminology empowers patients to recognize inconsistencies or ask informed questions. Authorities like the ISMP provide lists of dangerous abbreviations to avoid, and pharmacists are often trained to flag potentially confusing scripts before dispensing.

For a deeper look into the push for clearer communication, the Institute for Safe Medication Practices (ISMP) offers comprehensive resources, including lists of error-prone abbreviations and symbols on their website, which outlines the rationale for moving away from ambiguous medical shorthand.

Conclusion

On a medical prescription, the letter 'D' is a potent symbol with many potential meanings, from specifying a dose or frequency to instructing a patient to discontinue a medication. While medical abbreviations were historically necessary for speed, the inherent ambiguity and risk for serious medical error have led to a system-wide effort to phase them out. For patients, the best course of action is always to ask questions and ensure that all instructions are clear and understandable before leaving the pharmacy. Never assume what an abbreviation means; your health and safety depend on clarity.

Frequently Asked Questions

On a medical prescription, D/C is an abbreviation that stands for "discontinue" or "discharge." It is an instruction for the patient to stop taking a particular medication, or it may be noted in a patient's chart upon their discharge from a hospital.

The abbreviation OD is on national 'Do Not Use' lists because it can be misinterpreted in two different, critical ways. It can mean "once daily" (from the Latin omni die) for frequency, but in ophthalmology, it means "right eye" (oculus dexter). This ambiguity can lead to dangerous medication errors.

Yes, D can stand for several things depending on the context. Other abbreviations involving D include dieb. alt. ("every other day"), div. ("divide"), and D5W ("5% dextrose in water"). The context of the entire prescription is key to interpreting its meaning.

DAW stands for "Dispense As Written." This is a specific instruction from the prescribing healthcare provider to the pharmacist, indicating that the pharmacist should not substitute a generic version of the medication.

The best way to ensure correct interpretation is to ask your healthcare provider or pharmacist to explain the instructions clearly. Never assume the meaning of an abbreviation. All dispensed medications should have a printed label with spelled-out instructions that eliminate ambiguity.

q.o.d. stands for "every other day," whereas q.d. stands for "every day" or "once daily." This is a high-risk abbreviation pair because a misread o for a dot can lead to a patient taking their medication on the wrong schedule.

Medical abbreviations were historically used to save time, as many prescriptions were handwritten. They came from Latin phrases and became a form of shorthand. However, concerns about patient safety and a high potential for errors have led to a movement to use fewer abbreviations.