Medical Abbreviations on Pharmacy Prescriptions
BID, PO, XR, APAP, QHS, or PRN: Have you ever wondered what these odd, encrypted medical abbreviations mean on your prescription? Medical terminology is difficult enough, but how do you interpret these prescription directions written in code? Luckily you don’t have to; it’s the pharmacist’s job to put the medical abbreviation in plain english on your medication label. But there may be more to know about this shorthand than meets the eye.
Looking for the list of common medical abbreviations? Click here to access Table 1 below
Apothecary prescription abbreviations, like the ones you might see written by your doctor on your prescription or a hospital medication order, can be a common source of confusion for healthcare providers, too. In fact, an unclear, poorly written or wrong medical abbreviation that leads to misinterpretation is one of the most common and preventable causes of medication errors. All abbreviations can increase the risk for incorrect interpretation and should be used with caution in the healthcare setting.
Healthcare agencies, such as the Food and Drug Administration (FDA) and the Institute for Safe Medication Practices (ISMP) have made it a priority to communicate information about confusing abbreviations and medical shorthands. Health care facilities and practitioners are expected to take action and set internal standards to prevent these common - and potentially dangerous - medical errors.
Don’t Computers Solve The Problem With Abbreviations?
Some of the typed or computer-generated abbreviations, prescription symbols, and dose designations can still be confusing and lead to mistakes in drug dosing or timing. In addition, when these abbreviations are unclear, extra time must be spent by pharmacists or other healthcare providers trying to clarify their meanings, which can delay much-needed treatments.
Historically, poor penmanship and lack of standardization was the root cause of many of the prescription errors. Today, many prescriptions are now submitted via electronic prescribing (e-prescribing), electronic medical records (EMRs), and computerized physician order entry (CPOE), which has helped to lower the rates of these medical errors. However, discrepancies in electronic prescriptions are common and can lead to medical errors and possible patient harm.
If you receive a prescription label with unclear and confusing directions, always call your doctor right away to check on the correct information.
Drug Name Abbreviations
Drug names may often be abbreviated, too. For example, complicated treatment regimens, like cancer treatment protocols or combination HIV regimens, may be written with drug name abbreviations.
As reported by the FDA, a prescription with the abbreviation “MTX” has been interpreted as both methotrexate (used for rheumatoid arthritis) or mitoxantrone (a cancer drug). “ATX” was misunderstood to be the shorthand for zidovudine (AZT, an HIV drug) or azathioprine (an immunosuppressant drug). These types of errors can be linked with severe patient harm.
Numbers can lead to confusion and drug dosing errors, too.
- As an example, a prescription for “furosemide 40 mg Q.D.” (40 mg daily) was misinterpreted as “QID” (40 mg four times a day), leading to a serious medical error.
- Another example has to do with drug dosage units: doses in micrograms should always have the unit spelled out, because the abbreviation “µg” (micrograms) can easily be misread as “mg” (milligrams), creating a 1000-fold overdose.
Trailing zeros on medication orders
Numbers can also be misinterpreted with regards to decimal points. As noted in the Joint Commission's Do Not Use List, a trailing zero (for example, "5.0" mg, where the zero follows a decimal point) can be misinterpreted as “50” mg leading to a 10-fold overdose. Instead the prescriber should write “5 mg” with no trailing zero or decimal point after the number. Also, the lack of a leading zero, (for example, .9 mg) can be misread as “9” mg; instead the prescriber should use “0.9 mg” to clarify the strength.
The Joint Commission notes an exception to the Trailing Zero warning. They state that a “trailing zero” may be used only where needed to demonstrate the level of precision of the value being reported, such as for laboratory results, imaging studies that report size of lesions, or catheter or tube sizes. It may not be used in medication orders or other medication-related documentation.
Common abbreviations are often used for modified-release types of technology for prescription drugs, although no true standard exists for this terminology.
- Many drugs exist in special formulation as tablets or capsules -- for example as ER, XR, and SR -- to slow absorption or alter where the dissolution and absorption occurs in the gastrointestinal tract.
- Timed-release technology allows drugs to be dissolved over time, allows more steady blood concentrations of drugs, and can lower the number of times a drug must be taken per day compared to immediate-release (IR) formulations.
- Enteric-coated formulations, such as enteric-coated aspirin, help to protect the stomach by allowing the active ingredient to bypass dissolution in the stomach and instead dissolve in the intestinal tract.
Ways For Health Care Providers To Avoid Medication Errors
- Completely write out (or select electronically) the prescription, including the drug name and dosage regimen. The full dosage regimen includes the dose, frequency, duration, and route of administration of the drug to be administered.
- When writing out a dose, DO NOT use a trailing zero and DO use a leading zero.
- For veterinarians, when calling in or writing out a human drug prescription for an animal, verbally state or write out the entire prescription because some pharmacists may be unfamiliar with veterinary abbreviations.
- Use a computerized prescription system and electronic delivery of prescriptions to minimize misinterpretation of handwriting.
- Institutions should regularly educate and update healthcare providers and other employees on proper use of abbreviations.
- Report adverse events that stem from medication errors or abbreviations errors to the FDA; these events can be used to further inform and expand recommendations for safety.
Practitioners, including physicians, nurses, pharmacists, physician assistants and nurse practitioners, should be very familiar with the abbreviations used in medical practice and in prescription writing. All drug names, dosage units, and directions for use should be written clearly to avoid misinterpretation.
Pharmacists should be included in teams that develop or evaluate EMRs and e-prescribing tools. According to the Joint Commission, health care organizations can develop their own internal standards for medical abbreviations, use a published reference source with consistent terms, and should ensure to avoid multiple abbreviations for the same word. Internal enforcement, regular review and consistency are always the key.
What Can You Do As a Patient?
- Ask your doctor how you are supposed to take your medication before you leave the office, and write it down for future reference.
- Consider taking a trusted family member or friend to your medical appointments to help you to record important instructions.
- If you receive a prescription with unusual, unexpected or confusing directions, be sure to double check with your doctor.
- FDA encourages all healthcare providers, patients and consumers to report medication errors to the FDA Medwatch Program. The FDA is then aware of potential problems and can provide effective interventions that will minimize further errors. Timely prevention of medical errors can save a patient’s life.
Table 1: Common Medical Abbreviations
Note: This is not a complete list of medical abbreviations or error-prone abbreviations. Always speak with your healthcare provider for any questions related to medical abbreviations or terms.
|Abbreviation||Meaning / Intended Meaning||Notes About Confusion|
|1/2NS||one-half normal saline (0.45%)||Normal saline (NS) is 0.9%, so one-half normal saline is 0.45%|
Can be misinterpreted as five tablets of aspirin (per FDA).
Spell out full drug name.
|AAA||abdominal aortic aneurysm (called a "triple-A")||Can be misinterpreted as 'apply to affected area'|
|AAA||apply to affected area||Can be misinterpreted as 'abdominal aortic aneurysm'|
|achs||before meals and at bedtime|
|ad lib||freely; as much as desired|
|ad sat.||to saturation|
|ad.||to; up to||Caution not to confuse with AD (meaning right ear)|
|alt. h.||every other hour|
|am, A.M.||in the morning; before noon|
|APAP||acetaminophen||Spell out drug name "acetaminophen"|
|aPTT||activated partial thromboplastin|
|a.s., AS||left ear|
|ASA||aspirin||Spell out drug name "aspirin"|
|ATC||around the clock|
|AU||each ear; both ears|
Can be misinterpreted as azathioprine (per FDA).
Spell out drug name.
|BCP||birth control pills|
|bid, BID||twice a day|
|BMI||body mass index|
|BPH||benign prostatic hypertrophy|
|BSA||body surface area|
|BT||bedtime||In U.S., 'hs' or 'HS' is more commonly used for bedtime.|
|C&S||culture and sensitivity|
|CABG||coronary artery bypass graft|
|CAD||coronary artery disease|
|CAP||cancer of the prostate||Do not confuse with "capsule"|
|cap.||capsule||Do not confuse with "cancer of the prostate"|
|CBC||complete blood count|
May be mistaken as u (units) per ISMP.
Use mL instead of cc.
|CNS||central nervous system|
Can be misinterpreted as chlorpromazine (per FDA).
Spell out drug name.
|D/C, dc, disc.||discontinue OR discharge||Multiple possible meanings; spell out instead of using "D/C"|
|D5/0.9 NaCl||5% dextrose and normal saline solution (0.9% NaCl)|
|D5 1/2/NS||5% dextrose and half normal saline solution (0.45% NaCl)|
|D5NS||dextrose 5% in normal saline (0.9%)|
|D5W||5% dextrose in water|
|DAW||dispense as written|
|DBP||diastolic blood pressure|
|DO||Doctor of Osteopathic Medicine|
|DOB||date of birth|
|DPT||diphtheria-pertussis-tetanus||Better to spell out vaccine name; can be misinterpreted as Demerol-Phenergan-Thorazine per FDA|
|DVT||deep vein thrombosis|
|DW||dextrose in water, diabetes mellitus or distilled water||Multiple possible meanings; spell out instead of using "DW"|
|EENT||Eye, Ear, Nose, and Throat|
|ER||extended-release||Can also mean "emergency room"|
|ER||emergency room||Can also mean "extended-release"|
|f or F||female|
|FBS||fasting blood sugar|
|FDA||Food and Drug Administration|
|FFP||fresh frozen plasma|
|fl or fld||fluid|
|G, or g, or gm||gram||"g" is preferred symbol|
|GERD||gastroesophageal reflux disease|
|gr.||grain||Apothecary measurement (obsolete and may be misinterpreted as gram; do not use)|
|GTT||glucose tolerance test||Can be confused with gtt for drops|
|gtt, gtts||drop, drops||Can be confused with GTT for glucose tolerance test|
|guttat.||drop by drop|
|h, or hr.||hour|
|H&H||hematocrit and hemoglobin|
|HAART||highly active antiretroviral therapy|
|HCT, or Hct||hematocrit|
|HCT||hydrocortisone||Better to spell out drug name; can be misinterpreted as hydrochlorothiazide per FDA|
|HCTZ||hydrochlorothiazide||Better to spell out drug name; can be misinterpreted as hydrocortisone per FDA|
|HS||half-strength||better to spell out; do not mistake for "bedtime"|
|hs or HS||at bedtime, hours of sleep||Do not misinterpret as 'half-strength'|
|IBW||ideal body weight|
|ID||intradermal OR infectious disease||Multiple possible meanings; spell out word instead of using "ID"|
|IJ||injection||better to spell out 'injection'|
|IU||international unit(s)||Mistaken as IV (intravenous) or the number 10 (ten); Instead use "International Unit(s)" (per Joint Commission's "Do Not Use" List of Abbreviations)|
|IVP||intravenous push||Could be confused with 'intravenous pyelogram'|
|L or l||liter||Lowercase letter l may be mistaken as the number 1 (per ISMP). Instead use L (uppercase) for liter.|
|LFT||liver function tests|
|LMP||last menstrual period|
|LPN||licensed practical nurse|
|LR||lactated ringer (solution)|
|mane||in the morning|
|mcg or µg||microgram||Can be misinterpreted to mean "mg" or milligram, better to spell out 'microgram'|
|mEq/L||milliequivalent per liter|
|MgSO4||magnesium sulfate||May be confused with "MSO4" (morphine sulfate), spell out "magnesium sulfate" - Joint Commission's "Do Not Use" List of Abbreviations|
|mL||milliliter||Do not use ml as lowercase l may be mistaken for the number 1. Use mL (lowercase m, uppercase L) for milliliter (per ISMP).|
|MM or M||million||May be mistaken as thousand. Use million.|
|M or K||thousand||May be mistaken as million. Use thousand.|
|mm of Hg||millimeters of mercury|
|mol wt||molecular weight|
|MS||morphine sulfate or magnesium sulfate||Can mean either morphine sulfate or magnesium sulfate, spell out full drug name - Joint Commission's "Do Not Use" List of Abbreviations|
|MSO4||morphine sulfate||May be confused with "MgSO4"; instead spell out "morphine sulfate" - Joint Commission's "Do Not Use" List of Abbreviations|
|n or noct.||in the night|
|N/V, N&V||nausea and vomiting|
|NDC||National Drug Code|
|Ng or ng||nanogram||May be mistaken as mg or nasogastric. Use nanogram.|
|NKA||no known allergies|
|NKDA||no known drug allergies|
|noct. maneq.||night and morning|
|NPO, n.p.o.||nothing by mouth||Preferred by AMA to spell out "nothing by mouth"|
|NSAID||nonsteroidal anti-inflammatory drug|
|NTE||not to exceed|
|o.d., OD||right eye||Can also mean "overdose" or "once daily"; better to spell out "right eye"|
|o.d.||once per day||Preferred in the UK; Can also mean "overdose" or "right eye"; better to spell out "once per day"|
|o.s., OS||left eye|
|PO||orally or by mouth||May be better to spell out "by mouth" or "orally" (per AMA)|
|q4h||every 4 hours|
|q6h||every 6 hours|
|q8h||every 8 hours|
|q12h||every 12 hours|
|qd, QD, q.d., Q.D.||every day||Can be mistaken as q.i.d. Instead write "daily" (per The Joint Commission "Do Not Use List") or "use daily" per ISMP list|
|qhs||each night at bedtime||Can be confused with "qh" (every hour); better to spell out "each night at bedtime"|
|q.i.d. , QID||four times a day|
|qod, QOD, q.o.d., or Q.O.D.||every other day||
May be mistaken as qid or QID (four times daily).
Write "every other day" (per ISMP and The Joint Commission).
|SL, s.l.||sublingual (under the tongue)|
|SC, SQ sq, or sub q||subcutaneous or subcutaneously||Use SUBQ (all uppercase) or spell out subcutaneous or subcutaneously|
|STD||sexually transmitted disease|
|tbsp or Tbsp||tablespoon||Mistaken as teaspoon(s). Use the metric system (e.g., mL).|
|TID, t.i.d.||three times a day|
|tsp||teaspoon||Mistaken as tablespoon(s). Use the metric system (e.g., mL).|
|U or u||unit||Mistaken as the number "0" (zero), the number "4" (four) or as "cc". Write "unit" instead (per The Joint Commission "Do Not Use" List).|
|ud, ut, dict, UD||as directed|
|UTI||urinary tract infection|
|WBC||white blood cell|
|mcg, µg||microgram||µg mcg can be misinterpreted as "mg". Better to spell out "microgram"|
- Are expired drugs still safe to take?
- Can grapefruit juice interact with my medications?
- Common Drug Side Effects
- Generic Drug FAQs
- How do I remember to take my medications?
- How do I stop my medication safely?
- How to Safely Dispose of Your Old Medications
- Imprint Code FAQs - For Oral Medications
- Injection Types and Sites
- Medical Conversions - How many ml in a teaspoon?
- Pill splitting - Is it safe?
- Top 5 Ways to Avoid Drug Errors
- Top 9 Ways to Prevent a Deadly Drug Interaction
- What are pharmaceutical salt names?
- What are the risks vs. benefits of medications?
- What is the half-life of a drug?
- What is the placebo effect?
- Taber’s Medical Abbreviations. Tabers Online. Accessed July 13, 2021 at https://www.tabers.com/tabersonline/view/Tabers-Dictionary/767492/all/Medical_Abbreviations
- The Joint Commission Fact Sheet. Official “Do Not Use” List. August 2020 Update Accessed July 14, 2021 at https://www.jointcommission.org/-/media/tjc/documents/fact-sheets/do-not-use-list-8-3-20.pdf
- Mahumud A, Phillips J, Holquist C. Stemming drug errors from abbreviations. FDA Safety Page. Drug Topics. July 1, 2002.
- FDA. MedWatch: The FDA Safety Information and Adverse Event Reporting Program. Accessed July 14, 2021 at https://www.fda.gov/safety/medwatch-fda-safety-information-and-adverse-event-reporting-program
- FDA Consumer Updates. FDA and ISMP Work to Prevent Medication Errors. Drugs.com. March 29, 2012. Accessed July 14, 2021 at https://www.drugs.com/fda-consumer/fda-and-ismp-work-to-prevent-medication-errors-213.html
- FDA. Animal and Veterinary. A Microgram of Prevention is Worth a Milligram of Cure: Preventing Medication Errors in Animals. June 12, 2019. Accessed July 14, 2021 at https://www.fda.gov/animal-veterinary/resources-you/microgram-prevention-worth-milligram-cure-preventing-medication-errors-animals
- ISMP List of Error-Prone Abbreviations, Symbols, and Dose Designations. Institute for Safe Medication Practices (ISMP). 2021. Accessed July 14, 2021 at https://www.ismp.org/recommendations/error-prone-abbreviations-list
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.