Understanding Prescription Abbreviations

You may have seen prescription abbreviations like qd, hs, or bid on your medication labels, which are derived from the latin words for "every day," "at bedtime," and "twice daily," respectively.

Perhaps one of the most common is Rx, which is the official symbol for "prescription." Thought to be derived from the latin word for "recipe," this abbreviation relays to pharmacists that a prescription is authorized to be filled.

Your pharmacy will translate your healthcare provider's instructions on the medicine's label. Sometimes, though, a mistake can happen. Many drugs, like arthritis medication or pain medication, can be dangerous if you take the wrong dose. Knowing how to read prescription abbreviations can protect you from harmful errors.

This article will discuss the Latin abbreviations healthcare providers use on prescriptions and help you learn how to translate them. It will also discuss steps you can take to protect yourself from prescribing errors.

5 common prescription abbreviations

Verywell / Ellen Lindner

The Origins of "Rx" as an Abbreviation for "Prescription"

Rx is an abbreviation for "prescription." In the U.S. it is believed that the origin of the symbol is an abbreviation of the Latin word for "recipe," which means "take."

In Europe, another suggestion of the origin of the symbol appears to represent the astronomical sign of the planet Jupiter.

According to another theory, the Rx symbol is based on the Roman deity Jupiter. Jupiter's symbol looked similar to the Rx symbol. The symbol may have been placed on a prescription to invoke Jupiter's blessing.

What Is the Difference Between Rx and Px?

Px and Rx are often confused for one another. However, Px does not mean prescription like Rx does. Depending on where it is used, Px can be a shorthand for "prognosis" or for "procedure code." As a procedure code, Px will precede a numerical code that represents a specific medical procedure indicated for a patient.

An Example of Prescription Abbreviations

Here is an example of what a healthcare provider might write on a prescription:

Sig: 1 tab po qid pc & hs

These abbreviations are instructions for taking the medication. The pharmacist will translate them for the medication label. In this case, the instructions will read: "Take one tablet by mouth four times a day, after meals, and at bedtime."

The abbreviations may be written in capital letters or small letters, and may or may not include periods.

List of Common Prescription Abbreviations

These are some common Latin prescription abbreviations and their meanings:

  • ac (ante cibum) means "before meals"
  • ad (auris dextra) means "right ear"
  • ad lib (ad libitum) means "use as much as desired"
  • aI, as (auris laeva, auris sinistra) means "left ear"
  • au (auris utraque) means "both ears"
  • bid (bis in die) means "twice a day"
  • cap, caps (capsula) means "capsule"
  • cf means "with food"
  • daw means "dispense as written"
  • dieb alt (diebus alternis) means "every other day"
  • emp (ex modo prescripto) means "as directed"
  • g means "gram"
  • gr means "grain"
  • gtt(s) (gutta) means "drop(s)"
  • IM means "intramuscular" with respect to injections
  • IV means "intravenous"
  • mdu (more dicto utendus) means "to be used as directed"
  • od (oculus dexter) means "right eye"
  • os (oculus sinister) means "left eye"
  • ou (oculus uterque) means "both eyes"
  • pc (post cibum) means "after meals"
  • po (per os) means "by mouth"
  • pr (per rectus) means "by rectum"
  • prn (pro re nata) means "as needed"
  • qad (quoque alternis die) means "every other day"
  • qd (quaque die) means "every day"
  • qh (quaque hora) means "every hour"
  • qhs (quaque hora somni) means "every night at bedtime"
  • q3h (quaque 3 hora) means "every three hours"
  • qid (quater in die) means "four times a day"
  • qwk means "every week"
  • sc, subc, subcut, subq, sq means "subcutaneous"
  • sig (signa) means "write"
  • tab (tabella) means "tablet"
  • tbsp means "tablespoon"
  • tsp means "teaspoon"
  • tid (ter in die) means "three times a day"
  • top means "topical"
  • ud, ut dict (ut dictum) means "as directed"
  • w means "with"
  • w/o means "without"
  • x means "times"

Declining Use of Prescription Abbreviations

The Latin terms are still in use, but some healthcare providers are retiring them. It is becoming more common for healthcare providers to write prescription instructions in plain language.

Readable prescriptions can help prevent medication errors. That is why many medical professionals believe written instructions should be used instead of hard-to-read abbreviations.

For example, the abbreviation qd, which means "daily," could be mistaken for qid, which means "four times a day." It could also be confused for od, which means "right eye." Simply writing "daily" prevents confusion.

E-prescribing, or electronic prescribing, can also help prevent medication errors. Instructions sent directly to the pharmacy electronically are less prone to human error. If your healthcare provider uses electronic prescribing, you may never see the abbreviations.

E-prescribing improves patient safety in a number of ways, such as:

  • Eliminating hard-to-read prescriptions
  • Reducing the need for verbal communication, which can lead to mistakes
  • Alerting the healthcare provider if the patient has a drug allergy
  • Alerting the healthcare provider to possible drug interactions
  • Making it easier for the healthcare provider to view the patient's medication history

Summary

Prescription abbreviations like b.i.d., which stands for "twice a day," and Rx, which stands for "prescription," are commonly used by healthcare providers when detailing prescription drug information in shorthand.

If you receive a written prescription, make sure you understand the directions. If the directions are unclear or confusing, ask your healthcare provider or pharmacist to explain. Don't take chances: Do not take your medication unless you understand the instructions.

4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Ohashi K. [Memorandum on the origin of Rx, the signal be employed to the heading in the prescription]. Yakushigaku Zasshi. 1995;30(2):91-95. PMID: 11613537

  2. Voice of America. Take this medicine: the story of the sign 'Rx'.

  3. Minnesota Health Related Licensing Boards. Partial list of prescription abbreviations.

  4. Porterfield A, Engelbert K, Coustasse A. Electronic prescribing: improving the efficiency and accuracy of prescribing in the ambulatory care settingPerspect Health Inf Manag. 2014;11(Spring):1g.

Carol Eustice

By Carol Eustice
Carol Eustice is a writer covering arthritis and chronic illness, who herself has been diagnosed with both rheumatoid arthritis and osteoarthritis.