Prescription Terminology

2. Roman Numerals in Prescriptions

  • Conversion required: Roman → Arabic numbers.

  • Rules:

    • Situation A (Addition): If second letter ≤ first letter → add.

      • Examples: VI = 6, II = 2, XV = 15.

    • Situation B (Subtraction + Addition): Apply subtraction first, then add.

      • Examples: XLIV = 44, CXXIV = 124, CCXLIX = 249.

  • Practice Conversions:

    • LIII = 53

    • XLIX = 49

    • CIX = 109

    • DXXIV = 524

    • MMVII = 2007

    • 18 = XVIII

    • 315 = CCCXV

    • 104 = CIV

    • 540 = DXL

    • 1496 = MCDXCVI

3. Duration of Dosing

  • Expressed as fractions:

    • Hours: x/24

    • Days: x/7

    • Weeks: x/52

    • Months: x/12

  • Examples:

    • 4 hours = 4/24

    • 5 days = 5/7

    • 6 weeks = 6/52

    • 4 months = 4/12

4. Dosage Frequency (Latin Abbreviations)

  • Daily frequency:

    • OD = once daily

    • BD/BID = twice daily

    • TDS/TID = three times daily

    • QDS/QID = four times daily

    • Q4H = every 4 hours

    • OM/MANE = every morning

    • ON/NOCTE = every night

    • n. et m. = night and morning

  • Meals/food:

    • cc = with food

    • ac = before food

    • pc = after food

  • Time of day:

    • am = before noon

    • pm = afternoon

    • h.s. = at bedtime

    • stat. = immediately

  • Miscellaneous:

    • prn = when required

    • ex aq = with water

    • mitte/mitt = send

5. Dosage Forms

  • Solid/Semi-solid:

    • Tab. = Tablet

    • Cap. = Capsule

    • Pulv. = Powder

    • Ung. = Ointment

    • Past. = Paste

    • Occulent. = Eye ointment

    • Troche. = Lozenge

    • Supp. = Suppository

  • Liquid:

    • Aq. = Water

    • Aqua dist. = Distilled water

    • Aurist. = Ear drops

    • Collun. = Nose wash

    • Collut. = Mouth wash

    • Collyr. = Eye wash

    • Elix. = Elixir

    • Emuls. = Emulsion

    • Linct. = Linctus

    • Liq. = Solution

    • Lot. = Lotion

    • Mist. = Mixture

    • Narist. = Nasal drops

    • Neb. = Spray

    • Pig. = Paint

    • Syr. = Syrup

    • Tine. = Tincture

6. Anatomy Abbreviations

  • Eye:

    • o. = Eye

    • o.l / o.s. = Left eye

    • o.d. = Right eye

    • o.u. = Both eyes

  • Ear:

    • Aur. = Ear

    • a.d. = Right ear

    • a.s / a.l. = Left ear

    • a.u. = Both ears

7. Miscellaneous Instructions

  • Mitte = to send/supply

  • Sig. = to label

  • Gutt./gtt. = drop

  • Md = as directed

  • Mdu = use as directed

  • Examples:

    • Sig. IV gutt o.u. qid prn → Label: 4 drops in both eyes, 4 times daily, as needed.

    • Sig. II gutt a.l. tds prn → Label: 2 drops in left ear, 3 times daily, as needed.

    • Sig. mdu prn → Label: Use as directed, when required.

  • Routes:

    • PO = oral

    • PR = rectal

    • PV = vaginal

    • PAA = apply to affected area

  • Conditions:

    • Pro dol = for pain

    • Pro tuss. = for cough