Common Prescription Abbreviations for Medication

Prescription abbreviations like qd, hs, or bid can sometimes be found on your medication labels. These abbreviations are derived from the Latin words for "every day," "at bedtime," and "twice daily," respectively.

Your pharmacy will translate your healthcare provider's medication instructions on the medicine's label. Sometimes, a mistake can happen, and a shorthand abbreviation will appear on your medication. So understanding these abbreviations can come in handy as well as indentifying common prescription abbreviation errors.

List of Common Prescription Abbreviations

It is unlikely that you will see Latin-based prescription abbreviations for medications you take at home. If they are on your prescription, your pharmacist is responsible for reviewing your medications with you and counseling you to ensure you understand your home medications.

If you ever pick up a prescription and see shorthand like these abbreviations, double-check their meaning with the pharmacist to ensure you take your medications as prescribed.

There are well over 150 prescription abbreviations. They include the following:

• ā: before something (such as a meal)
• aa: of each
• AA: apply to affected area
• a.c. (ante cibum): before meals
• achs: before meals and at bedtime
• a.d. (auris extra): right ear
• ad: up to
• ad lib (ad libitum): use as much as desired
• admov.: apply
• agit: shake or stir
• al, as (auris laeva, auris sinistra): left ear
• alt. h.: (alternis horis) every other hour
• amt: amount
• aq: water
• A.T.C.: around the clock
• au (auris utraque): both ears
• bib: drink
• bid or bd (bis in die): twice a day
• BM: bowel movement
• BP: blood pressure
• c or c̅: with
• cap, caps (capsule): capsule
• cc or cf: (cum cibos) with food
• comp: compound
• daw: dispense as written
• dc, D/C, disc: discontinue
• dieb alt (diebus alternis): every other day
• dil: dilute
• disp: dispense
• div: divide
• D.W.: distilled water
• E.C.: enteric coated
• elix: elixir
• emp (ex modo prescripto): as directed
• et: and
• ex aq: (ex aqua) in water
• fl, fld: fluid
• gal: gallon
• g: gram
• gr: grain
• gtt(s) (gutta): drop(s)
• h., hr., hor.: (hora) hour
• h.s. or hs: at bedtime
• ID: intradermal (into the skin)
• IM: intramuscular (into the muscle)
• inf: infusion
• inh: inhalation
• IV: intravenous
• lin: liniment
• liq: liquid
• M.: mix
• m, min: minimum
• max: maximum
• mcg: microgram
• mdu or m.d.u. (more dicto utendus): to be used as directed
• mEq: milliequivalent
• mg: milligram
• mL: milliliter
• nebul: nebulizer
• N.M.T.: not more than
• noct: at night
• non rep: (non repetatur) no repeats
• NS: normal saline (or 1/2NS for half normal saline)
• N.T.E.: not to exceed
  
• OD (oculus dexter): right eye
• OS (oculus sinister): left eye
• OTC: over the counter
• OU, o.u., or o_2 (oculus uterque): both eyes
• oint: ointment
• oz: ounce
• pc (post cibum): after meals
  
• per: by or through
• po (per os): by mouth
  
• pr (per rectus): by rectum
• prn or p.r.n.: (pro re nata): as needed
• pulv: powder
• q: every
• qad (quoque alternis die) or qod (quaque [other] die): every other day
• qam (quaque die ante meridiem): every morning
• qd (quaque die): every day
• qh (quaque hora): every hour
• qhs (quaque hora somni): every night at bedtime
• q1h: every hour (the 1 can be replaced with other numbers such as q12h or every 12 hours)
• q3h (quaque 3 hora): every three hours
• q4h: every four hours
• q6h: every six hours
• qhs: every bedtime
  
• qid (quater in die): four times a day
• qod: every other day
• qpm or q.p.m.: (quaque die post meridiem): every afternoon or every evening
• qqh: (quater quaque hora) every four hours
• qs: (quantum sufficiat) sufficient quantity
• qwk or QWK: every week
• R: rectal
• rep, rept: (repetatur) repeats
• Rx: prescription
• s or s.: (sine) without
• s.a.: (secundum artum) use your judgement
• s.o.s., si op., or sit: (si opus sit) if there is a need
• sc, subc, subcut, subq, sq: subcutaneous
  
• sig (signa): write
• SOB: shortness of breath
• soln: solution
• ss: (semis) one half
• supp: (suppositorium) suppository
• susp: suspension
• syr: syrup
• t.d.s.: (ter die sumendum) three times a day
• tab (tabella): tablet
• tbsp: tablespoon
• tid or t.i.d.: (ter in die): three times a day
  
• t.i.w: three times a week
  
• top: topical
• tr, tinc., or tinct.: tincture
• tsp: teaspoon
• ud, or ut dict: (ut dictum): as directed
• U.S.P.: United States Pharmacopoeia
• w: with
• w/f: with food
• w/o: without
• x: times
• X 10 d.: for 10 days
• Y.O.: years old

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

Rx is an abbreviation for "prescription." The abbreviation relays to pharmacists that a prescription is authorized to be filled. 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.

Common Abbreviation Errors

Although mistakes are rare, prescription errors may occur because of a misunderstanding regarding the abbreviations. Mistakes may occur due to unclear or messy handwriting or simply because of a typo.

Also, the presence of a period may cause some confusion. For example, the abbreviation "ad" means "up to," but "a.d." means "right ear." In other cases, however, the period doesn't make a difference. For instance, both "s" and "s." mean "without," regardless of the period.

In some cases, however, the use of a period can be misunderstood to look like a letter (such as a lowercase L) and that may cause an error. Other letters might also be misread. For example, an "a" can look like an "o" depending on the provider's handwriting style.

Common prescription abbreviation errors may include:

• a.u., a.s., a.d. or AD, AS, AU: If the "a" is mistaken for an "o," these abbreviations could erroneously indicate both, right, or left eye instead of both, right or left ear.
• bt: If the writing is not clear, this abbreviation that means "bedtime" could be read as BID, bd, or bid which means twice daily.
• d/c or D/C: This can mean to either discontinue or discharge.
• h.s., hs: This abbreviation which means "before bedtime" can be mistaken for HS which means "half strength" and vice versa.
• o.d.: While o.d. can mean "once daily," it can be confused for OD which means right eye. Also, in the case of o.d., o.s., or o.u. the "o" can be mistaken for an "a" and cause an error.
• q.d., QD, or q1d: These abbreviations are intended to indicate "every day" but they can be misread as "q.i.d." which means four times per day.
• q.o.d. or QOD: These abbreviations should mean "every other day" but the "o" can be misread as a period or as an "i" and interpreted as "q.i.d." or "four times per day."
• tiw or TIW: This abbreviation which means "three times per week" can be mistaken for "twice a week" or "three times per day."
• μg: This abbreviation for "microgram" can be mistaken for "mg" which means milligram.

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.

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.

Summary

Prescription abbreviations like "bid," 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: Ask a medical professional what the shorthand means before you take the prescription home.