Medical Abbreviations on Pharmacy Prescriptions
Medically reviewed by L. Anderson, PharmD Last updated on Jul 17, 2019.
BID, PO, XL, 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 medical abbreviations? Click here to access the table 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), The Joint Commisssion, 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 between structured and free-text fields in electronic prescriptions are common and can lead to medical errors and possible patient harm.
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), and “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 fatal 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) 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 write out “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. See the table for timed-release technology abbreviations.
Ways For Health Care Providers To Avoid Medication Errors
- Completely write out 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 animals, 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 educate 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. However, internal enforcement 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 or unexpected directions, be sure to double check with your pharmacist or doctor.
- FDA encourages all healthcare providers, patients and consumers to report medication errors to the FDA Medwatch Program so that the FDA can be made aware of potential problems and provide effective interventions that will minimize further errors. Timely prevention of medical errors can save a patient’s life.
Table: Common Medical and Prescription Abbreviations
|Abbreviation||Meaning / Intended Meaning||Notes About Confusion||Category|
|1/2NS||one-half normal saline (0.45%)||drug or class name|
|5-ASA||5-aminosalicylic acid||Better to spell out drug name; can be misinterpreted as five tablets of aspirin per FDA||drug or class name|
|AAA||abdominal aortic aneurysm (called a "triple-A")||Can be misinterpreted as 'apply to affected area'||medical condition|
|AAA||apply to affected area||Can be misinterpreted as 'abdominal aortic aneurysm'||route of administration|
|achs||before meals and at bedtime||time|
|AD||right ear||route of administration|
|ad lib||freely; as much as desired||time|
|ad sat.||to saturation||other|
|ad.||to; up to||Caution not to confuse with AD (meaning right ear)||measurement|
|alt. h.||every other hour||time|
|am, A.M.||in the morning; before noon||time|
|APAP||acetaminophen||Better to spell out drug name "acetaminophen"||drug or class name|
|aPTT||activated partial thromboplastin||lab|
|a.s., AS||left ear||route of administration|
|ASA||aspirin||Better to spell out drug name "aspirin"||drug or class name|
|ATC||around the clock||time|
|AU||each ear; both ears||route of administration|
|AZT||zidovudine||Better to spell drug name out; can be misinterpreted as azathioprine per FDA||drug or class name|
|Ba||barium||drug or class name|
|BCP||birth control pills||drug or class name|
|Bi||bismuth||drug or class name|
|bid, BID||twice a day||time|
|BMI||body mass index||vitals|
|BPH||benign prostatic hypertrophy||medical condition|
|BSA||body surface area||vitals|
|BT||bedtime||In U.S., 'hs' or 'HS' is more commonly used for bedtime||time|
|C&S||culture and sensitivity||lab|
|CABG||coronary artery bypass graft||other|
|CaCO3||calcium carbonate||drug or class name|
|CAD||coronary artery disease||medical condition|
|CAP||cancer of the prostate||Do not confuse with "capsule"||medical condition|
|cap.||capsule||Do not confuse with "cancer of the prostate"||dosage form|
|CBC||complete blood count||lab|
|cc||cubic centimeter||Can also mean "with food"||measurement|
|CD||controlled delivery||drug release technology|
|CF||cystic fibrosis||medical condition|
|CNS||central nervous system||other|
|CPZ||Compazine||Better to spell drug name out; can be misinterpreted as chlorpromazine per FDA||drug or class name|
|CR||controlled-release||drug release technology|
|cr, crm||cream||dosage form|
|D/C, dc, disc.||discontinue OR discharge||Multiple possible meanings; spell out instead of using "D/C"||other|
|D5/0.9 NaCl||5% dextrose and normal saline solution (0.9% NaCl)||drug or class name|
|D5 1/2/NS||5% dextrose and half normal saline solution (0.45% NaCl)||drug or class name|
|D5NS||dextrose 5% in normal saline (0.9%)||drug or class name|
|D5W||5% dextrose in water||drug or class name|
|DAW||dispense as written||other|
|DBP||diastolic blood pressure||lab|
|DKA||diabetic ketoacidosis||medical condition|
|DM||diabetes mellitus||medical condition|
|DO||Doctor of Osteopathic Medicine||medical specialty|
|DOB||date of birth||other|
|DPT||diphtheria-pertussis-tetanus||Better to spell out vaccine name; can be misinterpreted as Demerol-Phenergan-Thorazine per FDA||drug or class name|
|DR||delayed-release||drug release technology|
|DVT||deep vein thrombosis||medical condition|
|DW||dextrose in water, diabetes mellitus or distilled water||Multiple possible meanings; spell out instead of using "DW"||other|
|EC||enteric-coated||drug release technology|
|EENT||Eye, Ear, Nose, and Throat||Medical Specialty|
|ER||extended-release||Can also mean "emergency room"||drug release technology|
|ER||emergency room||Can also mean "extended-release"||other|
|ETOH||ethyl alcohol||drug or class name|
|f or F||female||other|
|FBS||fasting blood sugar||lab|
|FDA||Food and Drug Administration||other|
|Fe||Iron||drug or class name or lab|
|FFP||fresh frozen plasma||drug or class name|
|fl or fld||fluid||measurement|
|G, or g, or gm||gram||"g" is preferred symbol||measurement|
|garg||gargle||route of administration|
|GERD||gastroesophageal reflux disease||medical condition|
|gr.||grain||Apothecary measurement (obsolete and may be misinterpreted as gram; do not use)||measurement|
|GTT||glucose tolerance test||Can be confused with gtt for drops||lab|
|gtt, gtts||drop, drops||Can be confused with GTT for glucose tolerance test||measurement|
|guttat.||drop by drop||measurement|
|h, or hr.||hour||time|
|H&H||hematocrit and hemoglobin||lab|
|HAART||highly active antiretroviral therapy||drug or class name|
|HCT, or Hct||hematocrit||lab|
|HCT||hydrocortisone||Better to spell out drug name; can be misinterpreted as hydrochlorothiazide per FDA||drug or class name|
|HCTZ||hydrochlorothiazide||Better to spell out drug name; can be misinterpreted as hydrocortisone per FDA||drug or class name|
|HS||half-strength||better to spell out; do not mistake for "bedtime"||measurement|
|hs or HS||at bedtime, hours of sleep||Do not misinterpret as 'half-strength'||time|
|IBW||ideal body weight||lab|
|ID||intradermal OR infectious disease||Multiple possible meanings; spell out word instead of using "ID"||route of administration; other|
|IJ||injection||better to spell out 'injection'||route of administration|
|IM||intramuscular||route of administration|
|IN||intranasal||route of administration|
|inf||infusion||route of administration|
|inj.||injection||route of administration|
|instill.||instillation||route of administration|
|IP||intraperitoneal||route of administration|
|IR||immediate-release||drug release technology|
|IU||international unit||Mistaken as IV (intravenous) or 10 (ten); Instead spell out "units" per Joint Commission's "Do Not Use" List of Abbreviations||measurement|
|IUD||intrauterine device||dosage form|
|IV||intravenous||route of administration|
|IVP||intravenous push||Could be confused with 'intravenous pyelogram'||route of administration|
|IVPB||intravenous piggyback||route of administration|
|K||potassium||drug or class name|
|KOH||potassium hydroxide||drug or class name|
|LA||long-acting||drug release technology|
|LFT||liver function tests||lab|
|Li||lithium||drug or class name|
|LMP||last menstrual period||other|
|LPN||licensed practical nurse||medical specialty|
|LR||lactated ringer (solution)||drug or class name|
|mane||in the morning||time|
|mcg||microgram||Can be misinterpreted to mean "mg" or milligram, better to spell out 'microgram'||measurement|
|MD||medical doctor||medical specialty|
|MDI||metered-dose inhaler||dosage form|
|mEq/L||milliequivalent per liter||measurement|
|Mg||magnesium||drug or class name|
|MgSO4||magnesium sulfate||May be confused with "MSO4" (morphine sulfate), spell out "magnesium sulfate" - Joint Commission's "Do Not Use" List of Abbreviations||drug or class name|
|mm of Hg||millimeters of mercury||measurement|
|MMR||measle-mumps-rubella (vaccine)||drug or class name|
|mol wt||molecular weight||measurement|
|MR||modified-release||drug release technology|
|MS||morphine sulfate or magnesium sulfate||Can mean either morphine sulfate or magnesium sulfate, spell out drug name - Joint Commission's "Do Not Use" List of Abbreviations||drug or class name|
|MSO4||morphine sulfate||May be confused with "MgSO4"; instead spell out "morphine sulfate" - Joint Commission's "Do Not Use" List of Abbreviations||drug or class name|
|n or noct.||in the night||time|
|N/V, N&V||nausea and vomiting||other|
|Na||sodium||lab or drug or class name|
|NAS||intranasal||route of administration|
|NDC||National Drug Code||other|
|NGT||nasogastric tube||route of administration|
|NKA||no known allergies||other|
|NKDA||no known drug allergies||other|
|noct. maneq.||night and morning||time|
|NP||nurse practitioner||medical specialty|
|NPO, n.p.o.||nothing by mouth||Preferred by AMA to spell out "nothing by mouth"||route of administration|
|NS||normal saline||drug or class name|
|NSAID||nonsteroidal anti-inflammatory drug||drug or class name|
|NTE||not to exceed||other|
|OC||oral contraceptive||drug or class name|
|o.d., OD||right eye||Can also mean "overdose" or "once daily"; better to spell out||route of administration, ophthalmic abbreviations|
|o.d.||once per day||Preferred in the UK; Can also mean "overdose" or "right eye"; better to spell out||time|
|OM||otitis media||medical condition|
|o.s., OS||left eye||route of administration, ophthalmic abbreviations|
|o.u., OU||both eyes||route of administration, ophthalmic abbreviations|
|p.r.n., prn||as needed||time|
|PA||physician assistant||medical specialty|
|PE||physical exam, pulmonary embolism||other|
|per||by or through||route of administration|
|per neb||by nebulizer||route of administration|
|per os||by mouth, orally||AMA prefers to spell out "by mouth" or "orally"; can be mistaken as "os" meaning left eye per FDA||route of administration|
|PFT||pulmonary function tests||lab|
|pH||hydrogen ion concentration||other|
|PharmD||Doctor of Pharmacy||medical specialty|
|PMH||past medical history||other|
|PO, p.o.||orally or by mouth||AMA prefers to spell out "by mouth" or "orally"||route of administration|
|PR, p.r.||per the rectum||route of administration|
|PTT||partial thromboplastin time||lab|
|PV||per the vagina||route of administration|
|q.s., qs||as much as needed; a sufficient quantity||measurement|
|q12h||every 12 hours||time|
|q2h||every 2 hours||time|
|q3h||every 3 hours||time|
|q4h||every 4 hours||time|
|q6h||every 6 hours||time|
|q6PM, etc||every evening at 6 PM||time|
|q8h||every 8 hours||time|
|qd, QD||every day||Mistaken as q.i.d; Instead write "daily" or "every day" per Joint Commission's "Do Not Use" List of Abbreviations||time|
|qhs||each night at bedtime||Can be confused with "qh" meaning every hour; better to spell out||time|
|qid||four times a day||time|
|qn||Nightly or at bedtime||Not commonly used in U.S.; 'hs' more common for bedtime||time|
|qod, QOD, q.o.d||every other day||Can be mistaken as qd (daily) or qid (four times daily); Instead spell out "every other day" per Joint Commission's "Do Not Use" List of Abbreviations||time|
|q.s. ad||add sufficient quantity to make||measurement|
|RA||rheumatoid arthritis||medical condition|
|RDA||recommended daily allowances||other|
|RE||right eye||route of administration, ophthalmic abbreviations|
|RN||registered nurse||medical specialty|
|sa||according to the art; best practice||other|
|SA||sustained action||drug release technology|
|SBP||systolic blood pressure||vital sign|
|SID||Used ONLY in Veterinary medicine to mean "once daily"||Can be confused to mean BID (twice daily) and QID (four times daily); pharmacists should clarify abbreviations with DVM, if needed.||time; used in Veterinary medicine ONLY|
|sig codes||medical or prescription abbreviations||other|
|Sig.||write on label||other|
|SL, s.l.||sublingual, under the tongue||route of administration|
|SNRI||serotonin/norepinephrine reuptake inhibitor||drug or class name|
|SOB||shortness of breath||other|
|sol||solution; in solution||dosage form|
|sp gr||specific gravity||lab|
|SQ, SC, sub q||subcutaneously||Use caution as "SC" can be mistaken for "SL," meaning sublingual per FDA||route of administration|
|SR||sustained release||drug release technology|
|ss||sliding scale (insulin) OR 1/2 (apothecary; obsolete)||Use caution; can be misinterpreted; better to spell out "sliding scale" or "one-half"||other|
|SSI||Sliding scale insulin||other|
|SSRI||sliding scale regular insulin OR selective serotonin reuptake inhibitor||Spell out words to avoid confusion||other|
|STD||sexually transmitted diseases||medical condition|
|TIA||transient ischemic attack||medical condition|
|TID, t.i.d.||three times a day||time|
|tid ac||three times a day before meals||time|
|TIN, t.i.n.||three times a night||time|
|tinct., tr||tincture||dosage form|
|TIW, tiw||3 times a week||Spell out; can be confused with TID (three times a day)||time|
|top.||topical||route of administration|
|TPN||total parenteral nutrition||drug or class name|
|TR||timed-release||drug release technology|
|TSH||thyroid stimulating hormone||lab|
|U or u||unit||Mistaken as the number "0" (zero), the number "4" (four), or "cc". Prescriber should instead spell out "unit" per Joint Commission's "Do Not Use" List of Abbreviations||measurement|
|ud, ut dict, UD||as directed||other|
|UTI||urinary tract infection||medical condition|
|vag, pv||via the vagina||route of administration|
|VLDL||very low density lipoprotein||lab|
|vol %||volume percent||measurement|
|w/v||weight in volume||measurement|
|WBC||white blood cell||lab|
|WNL||within normal limits||lab|
|XL||extended-release||drug release technology|
|XR||extended-release||drug release technology|
|XT||extended-release||drug release technology|
|Zn||zinc||drug or class drug or class name|
|μg, mcg||microgram||μg or mcg can be misinterpreted as "mg", better to spell out 'microgram'||measurement|
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- Taber’s Medical Abbreviations. Tabers Online. Accessed July 17, 2019 at https://www.tabers.com/tabersonline/view/Tabers-Dictionary/767492/all/Medical_Abbreviations
- The Joint Commission. Patient Safety and Performance Measurement Fact Sheets. Facts About the Official “Do Not Use” List of Abbreviations. June 2019 Accessed July 17, 2019 at https://www.jointcommission.org/about_us/patient_safety_fact_sheets.aspx
- Glassman P. The Joint Commission's “Do Not Use” List: Brief Review (NEW) In: Making Health Care Safer II: An Updated Critical Analysis of the Evidence for Patient Safety Practices. Rockville (MD): Agency for Healthcare Research and Quality (US); 2013 Mar. (Evidence Reports/Technology Assessments, No. 211.) Chapter 5.
- 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 17, 2019 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 17, 2019 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 17, 2019 at https://www.fda.gov/animal-veterinary/resources-you/microgram-prevention-worth-milligram-cure-preventing-medication-errors-animals
- The Joint Commission. Official “Do Not Use” List. Updated June 2019. Accessed July 17, 2019 at https://www.jointcommission.org/assets/1/18/Do_Not_Use_List_6_28_19.pdf
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.