Top 150 Prescription Abbreviations & Medical Meanings (2024)

Medically reviewed by Leigh Ann Anderson, PharmD. Last updated on May 22, 2024.

Time and frequency abbreviations

  • ā: Before (Latin: ante). Indicates that medication should be taken before something, typically a meal. For example, "medication ā breakfast" means the medication should be taken before breakfast.
  • ac: Before meals (Latin: ante cibum). Indicates medication should be taken before a meal to ensure effectiveness or reduce side effects.
  • achs: Before meals and at bedtime (Latin: ante cibum et hora somni). Indicates that medication should be taken before each meal and also at bedtime.
  • bid: Twice a day (Latin: bis in die). Indicates medication should be taken twice daily at evenly spaced intervals, typically every 12 hours, for maximum therapeutic benefit.
  • : With (Latin: cum). Indicates that medication should be taken together with something else, such as food or another medication.
  • HS: At bedtime (Latin: hora somni). Indicates medicine should be taken before sleep at bedtime, ensuring effectiveness overnight or minimizing drowsy or sleep-related side effects. Best practice: Use upper case HS; lower case “hs” may be mistaken for half-strength.
  • h/o: History of. Denotes a past or current medical condition. For example, “h/o seizures”.
  • : After (Latin: post). Indicates that medication should be taken after an event. For example, "medications p̄ dialysis" means medications should be taken after dialysis.
  • p.c: After meals (Latin: post cibum). Indicates to take the medicine after a meal.
  • P.M: In the evening (Latin: post meridiem). Indicates to take the medicine in the evening.
  • PMH: Past medical history. Typically a listing of former/current medical conditions experienced by the patient, for example: hypertension, depression or type 2 diabetes.
  • PRN: as needed (Latin: pro re nata). Indicates that medication should be taken only when necessary; for example, for relief of symptoms such as pain, anxiety, or allergies instead of a regular schedule.
  • Stat: Immediately (Latin: statim). Indicates medication should be taken right away.
  • qd, QD**: Every day (Latin: quaque die). Indicates medication should be taken once daily. Best practice: Avoid using qd; instead write "daily" to avoid confusion with qid (four times a day).
  • qh: Every hour (Latin: quaque hora). Take or use every hour.
  • qhs: Every night at bedtime (Latin: quaque hora somni). Indicates that medication should be taken every night at bedtime and before sleep. Best practice: Spell out "every night at bedtime" to ensure clarity and avoid confusion with qh (every hour).
  • qid, QID: Four times a day (Latin: quater in die). Indicates medication should be taken four times daily at evenly spaced intervals, typically every six hours, for optimal effectiveness.
  • q6h: Every 6 hours (Latin: quaque 6 hora). Indicates medication should be taken every six hours.
  • qod, q.o.d, QOD, Q.O.D**: Every other day (Latin: quaque altera die). Indicates medication should be taken every other day. Best practice: Spell out "every other day" to avoid confusion with qd (every day) or qid (four times daily).
  • qs: As much as needed; a sufficient quantity (Latin: quantum satis).
  • : Without (Latin: sine). Denotes the medicine should be taken without something, such as, without food. For example, "medication s̅ food" means the medication should be taken without food. May also be abbreviated “w/o”.
  • s/p, sp: Status post (Latin: status post). Indicates a condition or procedure that occurred in the past, such as after surgery or an event. Best practice: Spell out "status post" to ensure clarity and avoid confusion in medical documentation.
  • TID, t.i.d: Three times a day (Latin: ter in die). Indicates medication should be taken three times daily at evenly spaced intervals, usually every eight hours, for optimal effectiveness.
  • qam: Every morning (Latin: quaque die ante meridiem). Used on prescriptions to indicate medication should be taken once every morning (before noon), typically to ensure the medication works throughout the day.
  • q8h: Every 8 hours (Latin: quaque 8 hora). Indicates medication should be taken every eight hours.
  • q12h: Every 12 hours (Latin: quaque 12 hora). Indicates medication should be taken every twelve hours.
  • ud, ut dict, UD: As directed (Latin: ut dictum). Indicates to take medicine according to the specific instructions provided by the healthcare provider.

Dosage form and route abbreviations

  • 1/2 tablet: One-half tablet. Best practice: Spell out "half tablet" or use reduced font-size fractions (½ tablet).
  • AD: Right ear. Best practice: Spell out "right ear"; may be mistaken for OD (right eye).
  • AS: Left ear. Best practice: Spell out "left ear"; may be mistaken for OS (left eye).
  • AU: Each ear or both ears (Latin: auris utraque). Best practice: Spell out "each ear"; may be mistaken for OU (each eye).
  • BSA: Body surface area. An estimate of the surface area of a person's body based on body weight and height. May be used to determine an individual’s drug dose, for example, with chemotherapy drugs.
  • cap: Capsule (Latin: capsula). Indicates medication is in capsule form. Best practice: Spell out "capsule" to avoid confusion with cancer of the prostate (CAP).
  • cr, crm: Cream. Best practice: Spell out cream as “cr” may be confused with “CR” (controlled release).
  • D/C, dc, or disc: Discontinue or discharge. Best practice: Spell out "discontinue" or "discharge" to avoid confusion.
  • EC: Enteric coated. A type of medication coating designed to prevent the drug from dissolving in the stomach. Instead, it dissolves in the intestines, which helps to protect the stomach lining from irritation or to ensure the medication is absorbed in the correct part of the digestive system. For example: enteric coated aspirin (EC aspirin).
  • elix: Elixir. Typically a sweet liquid composed of water, alcohol and flavorings used to compound medicines into an oral liquid form.
  • garg: Gargle. Indicates medicine should be gargled with orally in the mouth and throat area.
  • tab: Tablet. Indicates medication is in tablet form.
  • Inj, IJ: Injection (Latin: injectio). Indicates medication is administered via a needle. Best practice: Spell out "injection" to avoid confusion with intrajugular or intravenous (IV).
  • IM: Intramuscular. Indicates medication is injected into a muscle.
  • IN, NAS: Intranasal. Indicates the medication is administered through the nose, for example, intranasal corticosteroid sprays like Flonase or Nasacort. Best practice: Use all uppercase "NAS" or spell out "intranasal" to avoid confusion with IV or IM.
  • IR: Immediate-release. Indicates medicine moves into the bloodstream quickly, compared to a delayed- or extended-release dosage form.
  • IUD: Intrauterine device. A long-lasting contraceptive device inserted by a healthcare provider into the uterus to help prevent pregnancy.
  • IV: Intravenous. Indicates medication is administered through a vein.
  • IVP: Intravenous push. Denotes an injection that quickly delivers a single dose of medicine directly into the bloodstream.
  • LA: Long-acting. Indicates a medicine that works for a long period of time and may slowly release the drug into the bloodstream.
  • liq: Liquid.
  • lot: Lotion. Indicates a medicine dosage form typically applied to the skin.
  • NGT: Nasogastric tube. Thin plastic tube inserted through the nose, down the throat and into the stomach. May be used for nutrition, medication delivery or to give fluids when the patient cannot tolerate oral administration.
  • NPO: Nothing by mouth. Best practice: Spell out "nothing by mouth".
  • OC: Oral contraceptive. Indicates a birth control pill taken by mouth
  • OD: Right eye (Latin: oculus dexter). Best practice: Spell out "right eye"; may be confused with overdose or once daily.
  • OS: Left eye (Latin: oculus sinister). Best practice: Spell out "left eye"; may be mistaken for AS (right ear).
  • OU: Both eyes (Latin: oculus uterque). Best practice: Spell out "each eye"; may be mistaken for AU (each ear).
  • per neb: By nebulizer. Indicates medicine should be inhaled by a nebulizer device.
  • per os: By mouth. Best practice: Spell out "by mouth" or "orally"; can be mistaken as OS (left eye) per FDA.
  • PO, p.o: By mouth or orally. Indicates that medication should be taken through the mouth. Best practice: Spell out "by mouth" or "orally" to avoid confusion.
  • PV: Per vagin*. Denotes the medication is inserted into and administered via the vagin*.
  • PR: Per rectum. Indicates medication is administered via the rectum.
  • SL: Sublingual. Indicates medication is placed under the tongue to dissolve and be absorbed into the bloodstream.
  • sol: Solution, in solution. Indicates a medicine in a liquid preparation containing one or more drug substances dissolved in a solvent.
  • supp: Suppository. A suppository is a solid dosage form of medicine, often in bullet or oblong shape, that is inserted into the rectum, vagin* or urethra to deliver the medicine. One common example is a bisacodyl (Dulcolax) suppository used for constipation.
  • susp: Suspension. A suspension is a liquid dosage form of medicine with solid particles suspended in a liquid solution. One common example is amoxicillin suspension used for infections.
  • syr: Syrup. A syrup is an oral liquid medicine that contains a high content of sugar. An example is guaifenesin / dextromethorphan (Robitussin) cough syrup.
  • SQ, SC, sub q: Subcutaneous. Denotes an injection given by a needle just under the skin. Best practice: Use caution as SC can be mistaken for SL (sublingual) per FDA.
  • tinct, tr: Tincture. A tincture is a type of medicine that is made by dissolving a substance in alcohol. An example is tincture of iodine, an antiseptic used on the skin to help prevent an infection from cuts, abrasions or burns.
  • Troche: a lozenge (Latin: trochiscus). An oral dosage form that contains medicine and is allowed to dissolve in the mouth or on the tongue.
  • top: Topical. Typically means on the outside of the body (usually applied to the skin). An example is topical creams like hydrocortisone.
  • ung: Ointment (Latin: unguentum). An ointment is a dosage form that is made from an oily substance (for example petroleum jelly or anhydrous lanolin) to be applied to the skin. Ointments may act locally on the skin or be absorbed. A common example is triple antibiotic ointment (neomycin sulfate, polymixin B sulfate and bacitracin; brand name: Neosporin) used to help prevent infections in minor cuts and wounds.
  • XL, XR, XT: Extended-release. Indicates medication is formulated to release slowly over time.

Common medication abbreviations

  • 5-ASA: 5-aminosalicylic acid. Best practice: Spell out full drug name; may be misinterpreted as “5 aspirin tablets”.
  • APAP: Acetaminophen. Best practice: Spell out "acetaminophen"; not everyone is familiar with the abbreviation APAP.
  • ASA: Aspirin. Best practice: Spell out "aspirin" to avoid confusion.
  • AZT: Zidovudine. Best practice: Spell out "zidovudine"; can be mistaken for azithromycin, azathioprine, or aztreonam.
  • CPZ: Compazine (generic: prochlorperazine). Best practice: Spell out "Compazine"; can be misinterpreted as chlorpromazine.
  • CR: Controlled release. A controlled release formulation releases medicine at a predictable rate to achieve optimal, known drug concentrations in the blood.
  • DR: Delayed release. Indicates medication is formulated to release the medicine after taking it, often in a special part of the digestive tract. For example, enteric coated (EC) aspirin is designed to release in the intestine instead of the stomach to help lessen stomach upset.
  • ER: Extended release or emergency room. Extended release dosage forms release the medicine more slowly and it lasts longer, which means you may only need to take the medicine once per day instead of two or three times. Best practice: Spell out intended meaning to lessen confusion.
  • Fe: Iron. Iron is a common dietary mineral needed by your body for growth and development. It helps to make hemoglobin, a part of your red blood cells.
  • HCT: Hydrocortisone. A common cortisone cream sold over-the-the-counter in lower strength in the U.S. Used to help lessen redness, swelling an itching on the skin. Best practice:Spell out "hydrocortisone"; can be mistaken for hydrochlorothiazide.
  • HCTZ: Hydrochlorothiazide. A common diuretic medicine (“water pill”) to help lower water retention (edema) and blood pressure in the body. Best practice: Spell out "hydrochlorothiazide"; can be mistaken for hydrocortisone.
  • K: Potassium. An essential mineral (often called an electrolyte) found in foods and drinks and required by the body. Potassium supports fluid levels inside the cells, muscle function, and normal blood pressure.
  • KOH: Potassium hydroxide. Healthcare providers may use the KOH preparation test to diagnose a possible fungal infection. Also a caustic chemical (potash) also used in manufacturing.
  • MgSO4**: Magnesium sulfate. A naturally occurring mineral important for muscles and nerve function in the body. Magnesium sulfate also increases water in the intestines and may be useful for constipation. May be given by intravenous infusion in the hospital to help prevent seizures of preeclampsia or eclampsia. Magnesium sulfate granules are often called epsom salts (bath salts for soaking). Best practice: Spell out "magnesium sulfate" per Joint Commission's "Do Not Use" List; can be confused with MSO4 (morphine sulfate).
  • MSO4**: Morphine sulfate. A potent opioid medicine that may be used to treat severe pain. Best practice: Spell out "morphine sulfate" per Joint Commission's "Do Not Use" List; can be confused with magnesium sulfate (MgSO4).
  • NDC: National Drug Code. The National Drug Code is a unique 10- or 11-digit, 3-segment number, and a universal product identifier for human drugs in the United States. The 3 segments of the NDC identify the labeler, the product, and the commercial package size.
  • NSAID: Nonsteroidal anti-inflammatory drug. An NSAID is a commonly used over-the-counter (OTC) and prescription medicine used to treat inflammation, pain and fever. A common example is ibuprofen (brands: Advil, Motrin).
  • SNRI: Serotonin norepinephrine reuptake inhibitor. A class of antidepressant medication. A common U.S. example is venlafaxine (Effexor, Effexor XR). Best practice: Spell out “serotonin norepinephrine reuptake inhibitor” to avoid confusion.
  • SSRI: Selective serotonin reuptake inhibitor. A class of antidepressant medication. A common U.S. example is sertraline (Zoloft). Best practice: Spell out “selective serotonin reuptake inhibitor” to avoid confusion.
  • SR: Sustained release. SR Indicates a slower release and absorption of the drug with lower peak blood levels to help lessen side effects. One example is the antidepressant Wellbutrin SR (bupropion extended-release tablets) which can help reduce the risk of seizures with doses that are too high.
  • TSH: Thyroid stimulating hormone. TSH is a hormone in the body produced by the pituitary gland. It helps to stimulate thyroid hormone production by the thyroid gland which regulates the body’s metabolism.

Measurement and quantity abbreviations

  • cc: Cubic centimeter. Cubic centimeter is a metric measurement of volume. A cubic centimeter is also equal to one millimeter. Best practice: Use "mL" instead because "cc" can be mistaken for "u" (units).
  • g: Gram. Gram is a metric measurement of mass.
  • gr: Grain. An older unit for measurement equal to 0.065 grams. Best practice: Can be mistaken for gram; use the metric system.
  • gtt, gtts: Drop, drops. A dose description often used on a prescription for eye or ear medicines. For example, “instill 2 drops into the right ear”. Best practice: Use "drop" or "drops" because “gtt” can be confused with GTT for glucose tolerance test.
  • h, hr: Hour. A unit of time equal to 60 minutes.
  • IU**: International unit. A unit used to measure the activity of substances like hormones, enzymes, fat-soluble vitamins (like A, D, E and K), insulin and other medications. An International Unit is the amount of a substance that has a certain biological effect. Best practice: Spell out "units"; IU can be mistaken for IV (intravenous) or the number 10.
  • Mcg or ​​µg: Microgram. A metric unit of mass measurement equal to one thousandth of a milligram. Some medications are dosed in micrograms, for example, Actiq (fentanyl) transmucosal lozenge, a medicine used to treat "breakthrough" cancer pain not controlled by other medicines is dosed in micrograms. Best practice: Spell out "microgram" to avoid confusion with "mg" (milligram).
  • mg: Milligram. A metric measurement of mass and used commonly in drug dosing, for example “take 150 mg by mouth twice a day.” There are 1,000 milligrams in one gram.
  • mL: Milliliter. A metric measurement of volume and used commonly in drug dosing, for example “take 5 mL (1 teaspoonful) by mouth each morning.” Best practice: Use lower case "m" and upper case "L" for clarity (mL).
  • mm: Millimeter. A metric measurement of length. There are 1,000 millimeters in a meter and 10 millimeters in a centimeter.
  • vol: Volume. A unit of measurement equal to the amount of space an object takes up. For example, one cup (8 ounces) of water has a volume of 240 mL.
  • oz: Ounce. A fluid ounce is a liquid measure equal to 29.57 mL (often rounded up to 30 mL). An ounce is also equal to 28.35 grams (often rounded to 30 grams) when measuring mass. A common prescription abbreviation used in dosing or quantities.
  • Tbsp, T or tbs: Tablespoon. A tablespoon (or tablespoonful) is a measure equal to 15 mL or 1/2 of one fluid ounce. A common prescription abbreviation used to dose liquid medicines.
  • Tsp or t: Teaspoon. A teaspoon (or teaspoonful) is equal to 5 mL or 1/3 of a tablespoon. A common prescription abbreviation used to dose medicines.
  • U or u**: Unit. A common prescription abbreviation used to dose medicines like insulin. Best practice: Spell out "unit"; can be mistaken for "0" (zero), "4" (four), or "cc".
  • Lack of leading zero (.X mg)**: Indicates a dose without a leading zero before the decimal point. Best practice: Write "0.X mg" to avoid dosage errors.
  • Trailing zero (X.0 mg)**: Indicates a dose with an unnecessary trailing zero. Best practice: Write "X mg" to avoid misinterpretation; the decimal point may be missed.

Common medical conditions

  • CAD: Coronary artery disease. A narrowing or blockage of the blood vessels that supply blood and oxygen to the heart. Also commonly known as heart disease or atherosclerosis.
  • DM: Diabetes mellitus. A long-term medical condition marked by persistently high blood sugar (glucose) levels, little or no insulin production from the pancreas (to help regulate blood sugar), resistance to insulin (your body does not respond to insulin), or a combination of effects. Diabetes mellitus includes both Type 1 and Type 2 diabetes.
  • DVT: Deep vein thrombosis. A blood clot that forms in deep veins areas like the legs, thighs, hips, and arms, preventing normal blood flow. May cause pain and swelling and lead to a dangerous blood clot in the lung pulmonary embolism (PE).
  • GERD: Gastroesophageal reflux disease. Commonly called heartburn or acid indigestion. Symptoms may include a burning sensation and tightness in the mid-chest and digestive acids that flow backwards into the esophagus.
  • GI: Gastrointestinal. Related to the stomach and digestive tract area. Includes the mouth, pharynx (throat), esophagus, stomach, small intestine, large intestine, rectum, and anus.
  • GU: Genitourinary. Related to the urinary and reproductive organs. May include the kidney, bladder, testes, prostate gland, ureters, urethra, vagin*, uterus or cervix, among others.
  • HTN: Hypertension. Also commonly known as high blood pressure. High blood pressure makes your heart work much harder and can lead to heart damage. Typically defined as a blood pressure measurement of over 130/80 mmHg.
  • N&V: Nausea and vomiting. Feeling sick to your stomach, which may result in expulsion of stomach contents through the mouth. May occur due to a viral or bacterial infection like gastroenteritis (“stomach flu) or food poisoning.
  • PE: Pulmonary embolism. A dangerous clot (embolus) that can travel to your lung arteries and cause a blockage. May be caused by blood, fat, air or tumor cells. Maybe originate from a deep vein thrombosis (DVT)
  • RA: Rheumatoid arthritis. Long-term inflammatory disease that can occur in areas like the fingers, hands, wrists, feet, knees, ankles, hips and shoulders. causes pain, stiffness, warmth, redness and swelling in joints. Eventually, the affected joints may become deformed and damaged, especially without medical treatment.
  • UTI: Urinary tract infection. A urinary tract infection is caused by bacteria that get inside your urinary tract, which includes your kidneys, ureters, bladder, and urethra.
  • MD: Muscular dystrophy or Medical doctor. Muscular dystrophy is an inherited disease that causes muscle weakness and loss of muscle function, leading to trouble with walking, eating, drinking, or breathing. MD for medical doctor typically comes after a physician’s name, except when the doctor is a DO (doctor of osteopathy).

Medical and lab tests, procedures

  • C&S: Culture and sensitivity. A diagnostic laboratory test used to help identify bacteria or other pathogens in a suspected infection and appropriate antibiotics. Specimens collected can come from the blood, urine, lung secretions, sem*n, stool, wounds, and throat or nasal swabs. Can take several days or longer for the culture to fully grow.
  • CBC: Complete blood count. A common laboratory test that measures red blood cell (RBC) count (which includes hemoglobin [Hg] and hematocrit [Hct], white blood cell (WBC) count and platelets. RBCs carry oxygen and carbon dioxide, WBCs help fight infection and platelets help blood to clot to stop bleeding. A CBC may be done during a routine check-up or before surgery to help evaluate your overall health.
  • CXR: Chest x-ray. A computerized imaging test that provides black and white pictures of your lungs, ribs, heart, and diaphragm.
  • ECG/EKG: Electrocardiogram. A test that measures your heart’s electrical activity like your heart rate and rhythm to show how well it is working. It may be used to help diagnose heart diseases that have an irregular rhythm, a heart attack, or tachycardia (fast heart rate) or bradycardia (slow heart rate).
  • FBS: Fasting blood sugar. A blood sugar (glucose) test that is obtained when patients have typically not eaten or drinken anything but water for 8 to 12 hours. May be used to help diagnose prediabetes, diabetes or gestational diabetes. Normal fasting blood sugar levels are usually between 70 mg/dL (3.9 mmol/L) and 100 mg/dL (5.6 mmol/L).
  • HDL: High-density lipoprotein. A lipid protein found in the blood commonly referred to as “good” cholesterol It may be measured using a laboratory test and is often part of a standard adult panel. It helps move blood cholesterol to your liver where it's broken down and removed from your body.
  • LDL: Low-density lipoprotein. A blood lipid protein commonly referred to as “bad” cholesterol. It can build up in the artery walls and lead to heart disease. It may be measured using a laboratory test and is often part of a standard adult panel.
  • LFT: Liver function tests. A common group of blood tests, for example: alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), and gamma-glutamyl transferase (GGT) that that help to determine if you have liver disease.
  • PE: Pulmonary embolism or physical exam. A pulmonary embolism is a dangerous blood clot that can travel to the lung. A physical exam usually denotes a regular exam by a doctor that may occur annually to check your overall health and assess for preventive care like vaccines or any procedures you may need (for example: a colonoscopy or bone density test).
  • PFT: Pulmonary function tests. A group of breathing tests that measure how well the lungs are working; can help diagnose the cause of breathing problems or treatment effectiveness.
  • PT: Prothrombin time or physical therapy. Prothrombin time, also called a protime or INR, is a blood test that measures how long it takes for your blood to clot. Physical therapy denotes a plan of movements or exercises that can help your recovery after an injury or help you maintain your physical function.
  • WBC: White blood cell. A type of blood cell that is used to help fight off infections or cancerous cells. Examples of white blood cells include lymphocytes (T and B cells), granulocytes (neutrophils, eosinophils, and basophils) and monocytes.
  • WNL: Within normal limits. Indicates that test results, vital signs, or physical exam findings fall within the expected range, indicating no medical problems are detected.

Miscellaneous abbreviations

  • BP: Blood pressure. Denotes the amount of force your blood uses to get through your arteries to help deliver oxygen to your tissues. High blood pressure (HBP) is a common and serious medical condition.
  • BMI: Body mass index. Body mass index (BMI) is a number determined by using a person’s weight in kilograms divided by height in meters squared. Overweight and obesity ranges are determined by using the body mass index (BMI). BMI does not always take into account factors that may predict a healthy weight like muscle mass, bone density, age, sex, or ethnicity. The CDC considers a healthy adult BMI to be in the range of 18.5 to 24.9.
  • CNS: Central nervous system. Consists of the brain and spinal cord nervous system tissues. Helps to receive, transmit, process, and respond to information to elicit memory, muscle function, emotion, communication and sensory functions, among others.
  • DAW: Dispense as written. May be written on a prescription by the healthcare provider to the pharmacist. Indicates that the exact pharmaceutical product should be dispensed. There should be no substitution with alternative products or generics.
  • DOB: Date of birth. Indicated day, month and year of birth. Often used to help identify patients in a medical setting.
  • EENT: Eye, ear, nose, throat. A specialty practice for health care providers.
  • ENT: Ear, nose and throat. A specialty practice for health care providers.
  • FDA: Food and Drug Administration. The FDA is the official government agency in the United States that ensures public health and safety for human and animal medicines, medical devices, food supply and radioactive products.
  • HCP: Healthcare professional. A healthcare professional is someone whose occupation is to diagnose, monitor, prevent and treat health conditions. Includes occupations such as physicians, nurses, pharmacists, physical therapists and dentists.
  • NS: Normal saline. Refers to a 0.9% salt (sodium) solution that is commonly used intravenously to help replace fluids and treat dehydration, metabolic alkalosis and minor sodium loss.
  • NKA: No known allergies. Often indicated in a medical record that the patient does not have any known allergies to medicines, foods or other substances like latex.
  • NKDA: No known drug allergies. May be used in a medical record to denote that the patient does not have any known allergies to medicines, for example, to antibiotics or sulfa compounds.
  • OTC: Over-the-counter. Used to designate a medicine, dietary or herbal supplement, or other product that can be purchased without a prescription. For example, aspirin, Tylenol and Advil are all common OTC pain relief products.
  • PharmD: Doctor of Pharmacy. A higher educational degree obtained in some countries, including the U.S., Canada, Hungary, Italy, Japan and Thailand, among others. A Doctor of Pharmacy is a pharmacist and may also be registered with the State Board of Pharmacy in the state in which they practice.
  • Rx: Prescription from a healthcare provider, indicating the specific medication and dosage (or other item, like a procedure or test) to be taken or obtained by the patient. Today, most Rx’s are sent electronically to the pharmacy, lab or clinic.

Note: This is not a complete or endorsed list of medical or prescription abbreviations or error-prone abbreviations. The Joint Commission does not publish a list of approved abbreviations. Items below marked with ** are found on the Joint Commission's "Do Not Use" List of Abbreviations. Always speak with your healthcare provider for any questions related to medical abbreviations or terms.

Overview of abbreviations: How are they used?

You may wonder why healthcare providers use medical abbreviations like "1 tab po bid" for your prescription. Abbreviations, originally derived from latin words, are used to denote prescription directions or quantities, medical conditions or other health information in your medical records.

The prescription abbreviation "1 tab po bid" is interpreted like this:

  • the abbreviation "tab" means tablet and comes from the latin tabella
  • "po" means by mouth and comes from per os
  • "bid" means twice a day, and derives from bis in die.

When written out in plain language, these abbreviations mean "Take one tablet by mouth twice a day."

Luckily you don’t have to worry about interpreting these prescription directions yourself. It’s the pharmacist’s job to put the correct directions on your prescription label. But unclear or poorly written prescription abbreviations is one of the most common and preventable causes of medication errors.

  • To address these issues, 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, practitioners and electronic medical record systems have standards to help prevent these common and potentially dangerous medical errors.

Are medical abbreviations safe to use?

Historically, poor penmanship and lack of standardization was the root cause of many written paper prescription errors. Today, most prescriptions are 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.

Even with advances in technology, errors or misunderstanding in electronic prescriptions can occur. 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 medical treatments.

If you receive a prescription label with unclear and confusing directions, always call your doctor or pharmacist right away to double check the information.

What are the most common abbreviation errors?

1. Drug names

Drug names may be frequently abbreviated in medicine. For example, cancer treatment protocols or combination HIV regimens may be written with shortened drug name abbreviations. Examples of possible errors include:

  • Acetaminophen (Tylenol), a common over-the-counter pain medicine, is often shortened to "APAP" by healthcare providers, although ISMP states it should be spelled out instead, as not everyone recognizes this abbreviation.
  • 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” can be misunderstood to be the shorthand for zidovudine (AZT, an HIV drug) or azathioprine (an immunosuppressant drug).
  • "IU", which is intended to mean international units can be misinterpreted to mean IV (intravenous) or the number 10.
  • These types of errors may lead to significant patient harm.

2. Confusing numbers

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.

3. 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 when required to demonstrate the level of precision of the value being reported, such as for laboratory results, imaging studies that report the size of lesions, or catheter/tube sizes. It may not be used in medication orders or other medication-related documentation."

4. Modified-release dose forms

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.

How to prevent medication errors?

Healthcare providers can:

  • 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 help lower the risk of confusion due to poor handwriting.
  • Medical facilities 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.

In general, to avoid errors in the administration of medications and infusions, spell out the word instead of using an abbreviation. For example, use “international unit” instead of I.U.; “every day” instead of q.d.; “every other day” instead of q.o.d.; and “unit” instead of U.

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 that multiple abbreviations for the same word are avoided. Internal enforcement, regular review and consistency are always the key.

Joint Commission provides a list of mandatory "Do Not Use" abbreviations that must be applied to all orders, preprinted forms, and medication-related documentation (see notes in table below). Medication-related documentation can be either handwritten or electronic. Organizations are required by Joint Commission to follow this list of prohibited abbreviations, acronyms, symbols, and dose designations. However, the Joint Commission does not publish a list of approved abbreviations.

Bottom Line

What steps can you take as a patient to help prevent errors?

  1. Ask your doctor how you are supposed to take your medication before you leave the office, and write it down for future reference.
  2. Take your medicine bottles with you to the doctor's office so you can have all the information you need: drug name, dose, directions and any refills.
  3. Consider taking a trusted family member or friend to your medical appointments to help you write down any important instructions.
  4. Read the supplied plain language patient drug information that accompanies your prescription. If you do not have it, ask your doctor or pharmacist for a copy. Your healthcare professional can answer any questions about this information
  5. If you receive a prescription with unusual, unexpected or confusing directions, be sure to double check with your doctor and pharmacist. Don't be afraid to pick up the phone and call to ask. That's what they are there for.

FDA encourages all healthcare providers, patients and consumers to report medication errors to the FDA Medwatch Program. This program alerts the FDA to potential problems and allows them to take action to minimize further errors. Timely prevention of medical errors can save a patient’s life.

See also

  • Are expired drugs still safe to take?
  • Common Drug Side Effects
  • Does grapefruit juice interact with my medications?
  • Generic vs Brand Drugs: Your FAQs Answered
  • 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?

Sources

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circ*mstances.

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