# List of abbreviations used in medical prescriptions

This is a list of abbreviations used in medical prescriptions, including hospital orders (the patient-directed part of which is referred to as sig codes). This list does not include abbreviations for pharmaceuticals or drug name suffixes such as CD, CR, ER, XT (See Time release technology § List of abbreviations for those).
Capitalisation and the use of full stops are a matter of style. In the list, abbreviations in English are capitalized whereas those in Latin are not.
These abbreviations can be verified in reference works, both recent
and older. Some of those works (such as Wyeth 1901) are so comprehensive that their entire content cannot be reproduced here. This list includes all that are frequently encountered in today's health care in English-speaking regions.
Some of these are obsolete; others remain current.
There is a risk of serious consequences when abbreviations are misread or misinterpreted. In the United Kingdom, all prescriptions should be in English without abbreviation (apart from some units such as mg and mL; micrograms and nanograms should not be abbreviated). In the United States, abbreviations which are deprecated by the Joint Commission are marked in red; those abbreviations which are deprecated by other organizations, such as the Institute for Safe Medication Practices (ISMP) and the American Medical Association (AMA), are marked in orange.
The Joint Commission is an independent, non-profit, non-governmental organization which offers accreditation to hospitals and other health care organizations in the United States. While their recommendations are not binding on U.S. physicians, they are required of organizations who wish accreditation by the Joint Commission.

## Table

Key :
* Not recommended for use in the United States by the Joint Commission
* Not recommended for use by other organizations, such as the ISMP (Institute for Safe Medication Practices))
| Abbreviation or symbol | Latin, Greek, or Neo-Latin | English | Possible confusion |
| aa, āā, ĀĀ | ana | of each | |
| AAA | | apply to affected area | abdominal aortic aneurysm |
| a.c. | ante cibum | before meals | |
| a.c.h.s., ac&hs | ante cibum et hora somni | before meals and at bedtime | |
| a.d. | auris dextra | right ear | a single-storey a can be mistaken as an o which could read "o.d.", meaning right eye |
| ad., add. | adde addatur | add let there be added | |
| ad lib. | ad libitum | Latin, "at one's pleasure"; as much as one desires; freely | compare pro re nata, "as needed", which by convention includes an aspect of "up to some maximum". Similarly, compare s.o.s., q.l., and q.s. |
| admov. | admove admoveatur | apply [or] add add; let there be added | |
| ad us. | ad usum | according to custom | |
| æq. | æquales | equal | |
| agit. | agita | agitate (stir or shake) | |
| alt. d., alt. dieb. | alternis diebus | every other day; on alternate days | |
| alt. h., alt. hor. | alternis horis | every other hour; at alternate hours | |
| a.m. | ante meridiem | morning, before noon | |
| amp. | ampulla | ampule (ampul, ampoule) | |
| amt | | amount | |
| aq. | aqua | water | |
| aq. bull. | aqua bulliens | boiling water | |
| aq. com. | aqua communis | common water | |
| aq. dest. | aqua destillata | distilled water | |
| aq. ferv. | aqua fervens | hot water | |
| a.l., a.s. | auris laeva, auris sinistra | left ear | a can be mistaken as an o which could read "o.s." or "o.l", meaning left eye |
| ATC | | around the clock | |
| a.u. | auris utraque | both ears | a can be mistaken as an o which could read "o.u.", meaning both eyes |
| BDS, b.d.s. | bis die sumendum | twice daily | |
| bib. | bibe | drink | |
| bis | bis | twice | |
| b.i.d., b.d. | bis in die | twice daily | AMA style avoids use of this abbreviation (spell out "twice a day") |
| bis ind. | bis indies | twice a day | |
| bis in 7 d. | bis in septem diebus | twice a week | |
| BM | | bowel movement | commonly used in the United Kingdom when discussing blood sugar. From BM Stix – the measurement sticks used for calculating blood sugar; BM being an abbreviation of Boehringer Mannheim. |
| BNF | | British National Formulary | |
| bol. | bolus | as a large single dose (usually intravenously) | |
| BP, Ph.Br. | Pharmacopoeia Britannica | British Pharmacopoeia | |
| BS | | blood sugar | |
| BSA | | body surface area | |
| b.t. | | bedtime | mistaken for "b.i.d", meaning twice daily |
| bucc. | bucca | buccal (inside cheek) | |
| cap., caps. | capsula | capsule | |
| cap. | capiat | let him take (let the patient take) | |
| c.m. | cras mane | tomorrow morning | |
| c.m.s. | cras mane sumendus | to be taken tomorrow morning | |
| c̄, c. | cum | with (usually written with a bar on top of the c) | |
| cib. | cibus | food | |
| c.c. | cum cibo | with food [or] cubic centimetre | mistaken for U, meaning units; also has an ambiguous meaning; use "mL" or "millilitres" (1 cm$^3$ = 1 mL) |
| cf. | confer | compare | |
| c.n. | cras nocte | tomorrow night | |
| cochl. | cochleare | spoonful | |
| cochl. ampl. | cochleare amplum | an ample spoonful (a tablespoonful) | |
| cochl. infant. | cochleare infantis | a small spoonful (a teaspoonful) | |
| cochl. mag. | cochleare magnum | a large spoonful (a tablespoonful) | |
| cochl. mod. | cochleare modicum | a modest spoonful (a dessert-spoonful) | |
| cochl. parv. | cochleare parvum | a scant spoonful (a teaspoonful) | |
| colet. | coletur | let it be strained | |
| comp. | compositus | compound | |
| contin. | continuetur | let it be continued | |
| cpt. | capiat | let him take (let the patient take) | |
| cr., crm | | cream | |
| CST | | continue same treatment | |
| cuj. | cujus | of which | |
| c.v. | cras vespere | tomorrow evening | |
| cyath. | cyathus | a glassful | |
| cyath. vinos. | cyathus vinosus | a wine-glassful | |
| D, d. | die [or] dosis | days [or] doses | ambiguous meaning, write out "days" or "doses" |
| D5LR | | dextrose 5% in lactated Ringer's solution (intravenous sugar solution) | |
| D5NS | | dextrose 5% in normal saline (0.9%) (intravenous sugar solution) | |
| D5W, D$_5$W | | dextrose 5% in water (intravenous sugar solution) | |
| D10W, D$_{10}$W | | dextrose 10% in water (intravenous sugar solution) | |
| da | da | give | |
| DAW | | dispense as written (i.e., no generic substitution) | |
| DC, dc, D/C, disc | | discontinue [or] discharge | ambiguous meaning |
| decoct. | decoctum | decoction | |
| det. | detur | let it be given | |
| dieb. alt. | diebus alternis | every other day; on alternate days | |
| dil. | | dilute | |
| dim. | dimidius | one-half | |
| d. in p. æ. | divide in partes æquales | divide into equal parts | |
| disp. | | dispersible [or] dispense | |
| div. | divide | divide; let it be divided | |
| dL | | deciliter | |
| DS | | double strength | |
| d.t.d. | dentur tales doses | give of such doses | |
| DTO | | deodorized tincture of opium | can easily be confused with "diluted tincture of opium," which is 1/25th the strength of deodorized tincture of opium; deaths have resulted due to massive morphine overdose. Compare laudanum and paregoric. |
| DW | | distilled water [or] dextrose in water (intravenous sugar solution) | |
| elix. | elixir | elixir | |
| e.m.p. | ex modo prescripto | as directed (in the manner prescribed) | |
| emuls. | emulsum | emulsion | |
| et | et | and | |
| EOD | | every other day | |
| ex aq. | ex aqua | in water; with water | |
| exhib. | exhibiatur | let it be given | |
| f. | fiat | make; let it be made | |
| f.h. | fiat haustus | make a draught | |
| fl., fld. | fluidus | fluid (usually meaning specifically liquid in health care) | |
| f.m. | fiat mistura | make a mixture | |
| f. pil. | fiat pilula | make a pill | |
| f.s.a. | fiat secundum artem | make according to art | |
| ft. | fiat | make; let it be made | |
| g, gm | | gram (modern SI symbol is g, not gm) | |
| garg. | gargarisma | gargle | |
| gr. | granum | grain | |
| gtt(s) | gutta(e) | drop(s) | |
| gutt. | gutta(e) | drop(s) | |
| H | | hypodermic | |
| h, hr, hor. | hora | hour | |
| habt. | habeat | let him have | |
| hor. alt. | hora alternis | every other hour (every second hour; at alternate hours) | |
| hor. decub. | hora decubitus | at bedtime | |
| hor. intermed. | horis intermediis | at intermediate hours | |
| hor. tert. | horis tertiis | every third hour | |
| h.s. | hora somni (at the hour of sleep) | at bedtime [or] half-strength | ambiguous (2 meanings, easily conflated); spell out |
| IBW | | ideal body weight (for dosing based on clearance estimation) | |
| ID | | intradermal | |
| IJ, inj. | injectio | injection | mistaken for "IV", meaning intravenously |
| i.m., IM | | intramuscular | |
| IN | | intranasal | mistaken for "IM", meaning intramuscular, or "IV", meaning intravenously |
| ind. | indies | daily | |
| inf. | infusum | infusion (extraction) / intravenous infusion | |
| i | unus tabuletta | one tablet | |
| ii | duo tabuletta | two tablets | |
| iii | tres tabuletta | three tablets | |
| IO | | intraosseous | |
| IP | | intraperitoneal | |
| IT | | intrathecal | mistaken for other abbreviations; spell out |
| IU | | international unit | mistaken for "IV" or "10", spell out "international unit" |
| i.v., IV | | intravenous | |
| i.v.p., IVP | | intravenous push | |
| IVPB | | intravenous piggyback | |
| kg | | kilogram | |
| LAS | | label as such | |
| lat. dol. | lateri dolenti | to the painful side | |
| lb. | libra | pound | |
| l.c.d. | liquor carbonis detergens | coal tar solution | |
| lin | linimentum | liniment | |
| liq. | liquor | solution | |
| lot. | lotio | lotion | |
| M., m. | misce | mix | |
| M., m., mit., mitt. | mitte | send or dispense, e.g. number of tablets provided | Can be confused with m,. misce, context-dependent |
| mane | mane | in the morning | |
| max. | maximum | maximum | |
| mcg | | microgram | recommended replacement for "μg" which may be confused with "mg" |
| mdi | | metered dose inhaler | |
| m.d.u. | more dicto utendus | to be used as directed | |
| mEq | | milliequivalent | |
| mg | | milligram | |
| mg/dL | | milligrams per deciliter | |
| MgSO4 | | magnesium sulfate | may be confused with "MSO4", spell out "magnesium sulfate" |
| midi | | at midday | |
| min. | minimum [or] minim [or] minutum | minimum [or] minim [or] minute | |
| mist. | mistura | mixture | |
| mL | | millilitre | |
| mod. præscript. | modo præscripto | in the manner directed | |
| MS | | morphine sulfate or magnesium sulfate | can mean either morphine sulfate or magnesium sulfate, spell out either |
| MSO4 | | morphine sulfate | may be confused with "MgSO4", spell out "morphine sulfate" |
| nebul, neb. | nebula | a spray (such as for insufflation)- nebulizer | |
| NMT | | not more than | |
| noct. | nocte | at night | |
| non rep. | non repetatur | no repeats (no refills) | |
| NPO, n.p.o. | nil per os | nothing by mouth | AMA style avoids use of this abbreviation (spell out "nothing by mouth") |
| NS | | normal saline (0.9%) | |
| 1/2NS | | half-normal saline (0.45%) | |
| NTE | | not to exceed | |
| o 2, o$_2$ | | both eyes | "O$_2$" usually means oxygen or oxygen therapy |
| o.d. | omni die | every day (once daily) (preferred to "qd" in the UK) | |
| o.d. | oculus dexter | right eye | o can be mistaken as an a which could read "a.d.", meaning right ear, confusion with "omni die" |
| o.m. | omni mane | every morning | |
| omn. bih. | omni bihora | every 2 hours | |
| omn. hor. | omni hora | every hour | |
| o.n. | omni nocte | every night | |
| OPD | | once per day | |
| o.s. | oculus sinister | left eye | o can be mistaken as an a which could read "a.s.", meaning left ear |
| o.u. | oculus uterque | both eyes | o can be mistaken as an a which could read "a.u.", meaning both ears |
| oz | | ounce | |
| p. | perstetur | continue | |
| part. æq. | partes æquales | equal parts | |
| per | per | by or through | |
| p.c. | post cibum | after meals | |
| p.c.h.s., pc&hs | post cibum et hora somni | after meals and at bedtime | |
| Ph.Br., BP | Pharmacopoeia Britannica | British Pharmacopoeia | |
| Ph.Eur. | Pharmacopoeia Europaea | European Pharmacopoeia | |
| Ph.Int. | Pharmacopoeia Internationalis | International Pharmacopoeia | |
| pig./pigm. | pigmentum | paint | |
| p.m. | post meridiem | evening or afternoon | |
| p.o. | per os | by mouth or orally | AMA style avoids use of this abbreviation (spell out "orally") |
| ppt. | præparata | prepared | |
| p.r., PR | per rectum | rectally | |
| p.r.n., PRN | pro re nata | as needed | PRN is pertactin, a virulence factor of the bacterium that causes pertussis |
| pt. | perstetur | continue | |
| pulv. | pulvis | powder | |
| p.v., PV | per vaginam | vaginally | |
| q | quaque | every, per | |
| q.1 h, q.1° | quaque 1 hora | every 1 hour (can replace 1 with other numbers) | |
| q4PM | | at 4:00 pm (can replace 4 with other numbers) | mistaken to mean every 4 hours |
| q.a.d. | quaque alternis die | every other day | |
| q.a.m. | quaque die ante meridiem | every morning (every day before noon) | |
| q.d./q.1.d. | quaque die | every day | mistaken for "QOD" or "qds," AMA style avoids use of this abbreviation (spell out "every day") |
| q.d.a.m. | quaque die ante meridiem | once daily in the morning | |
| q.d.p.m. | quaque die post meridiem | once daily in the evening | |
| q.d.s. | quater die sumendus | 4 times a day | can be mistaken for "qd" (every day) |
| q.p.m. | quaque die post meridiem | every evening (every day after noon) | |
| q.h. | quaque hora | every hour | |
| q.h.s. | quaque hora somni | every night at bedtime | can be mistaken as "q.h.r." (every hour) |
| q.i.d. | quater in die | 4 times a day | can be mistaken for "qd" or "qod," AMA style avoids use of this abbreviation (spell out "4 times a day") |
| q.l. | quantum libet | as much as is requisite | |
| q.n. | quaque nocte | every night | can be mistaken as "q.h." (every hour) |
| q.o.d. | quaque altera die | every other day | mistaken for "QD," AMA style avoids use of this abbreviation (spell out "every other day") |
| q.q. | quaque | every; each | |
| q.q.h. | quater quaque hora | every 4 hours | |
| q.s. | quantum sufficiat (subjunctive), quantum sufficit (indicative), quantum satis | as much as suffices; a sufficient quantity | |
| q.s. a.d | add up to |
| q.v. | quantum volueris [or] quod vide | at will [or] which see | |
| QWK | | every week | |
| rep., rept. | repetatur | repeats | |
| RL, R/L | | Ringer's lactate | |
| Rx, R$_x$, RX, ℞, Rp | recipe | take (often effectively a noun meaning "prescription"—medical prescription or prescription drug) | |
| rep. | repetatur | let it be repeated | |
| s. | signa | write (write on the label) | |
| s.a. | secundum artem | according to the art (accepted practice or best practice) | |
| SC | | subcutaneous | "SC" can be mistaken for "SL," meaning sublingual. See also SQ |
| sem. | semen | seed | |
| s.i.d. | semel in die | once a day | used exclusively in veterinary medicine |
| sig. | signa, signetur | write (write on the label) | |
| s̄ | sine | without (usually written with a bar on top of the s) | |
| sing. | singulorum | of each | |
| SL, s.l. | sub lingua | sublingually, under the tongue | |
| SOB | | shortness of breath | |
| sol. | solutio | solution | |
| s.o.s., si op. sit | si opus sit | if there is a need | |
| s.s., SS | semisse | one-half [or] sliding scale | mistaken for "55" or "1/2" |
| SSI | | sliding scale insulin or sliding scale regular insulin | mistaken to mean "strong solution of iodine" or "selective serotonin reuptake inhibitor". See also SSRI |
| SQ | | subcutaneously | "SQ" can be mistaken for "5Q" meaning "5 every dose". See also SC |
| SSRI | | selective serotonin reuptake inhibitor [or] sliding scale regular insulin | ambiguous. Do not abbreviate |
| st. | stet | let it stand (for example, for settling) | |
| stat | statim | immediately | |
| SubQ., subcut | | subcutaneously | |
| sum. | sumat [or] sumendum | let him take [or] let it be taken | |
| supp. | suppositorium | suppository | |
| susp. | suspension | suspension | |
| syr. | syrupus | syrup | |
| tab. | tabella | tablet | |
| tal., t. | talus | such | |
| tbsp | | tablespoon | |
| t.d.s., TDS | ter die sumendum | 3 times a day | |
| t.i.d., t.d. | ter in die | 3 times a day | AMA style avoids use of this abbreviation (spell out "3 times a day") |
| tinct. | tinctura | tincture | |
| t.i.w. | | 3 times a week | mistaken for "twice a week" |
| top. | | topical | |
| TPN | | total parenteral nutrition | |
| tr, tinc., tinct. | tinctura | tincture | |
| trit. | triturate | grind to a powder | |
| troch. | trochiscus | lozenge | |
| tsp | | teaspoon | |
| U | | unit | mistaken for a "4", "0" or "cc", spell out "unit" |
| u.d., ut. dict. | ut dictum | as directed | |
| ung. | unguentum | ointment | |
| USP | | United States Pharmacopeia | |
| vag. | vagine | vaginally | |
| w | | with | |
| w/a | | while awake | |
| w/f | | with food (with meals) | |
| w/o | | without | |
| X, x | | times | |
| YO, y.o. | | years old | |
| μg | | microgram | mistaken for "mg", meaning milligram |
| @ | | at | mistaken for "2"; spell out "at" |
| > | | greater than | mistaken for a "7" |
| < | | less than | mistaken for an "L" |
| ℔ | libra | pound | |
| ℥ | uncia | ounce | |
| ʒ | drachma | dram (drachm) | |
| ℈ | scrupulus | scruple | |
| ° | | hour | |

## Currently discouraged practices

* Abbreviating names of drugs
* Using apothecary's units
* Using trailing zeros or not using a leading zero