Prescription & Dosage
b.i.d. (BID)
Bis in die (Twice a day)Instructs the patient to take the dose twice daily, usually approximately 12 hours apart.
Clinical & Prescription Reference Dictionary
Medical & Prescription Abbreviations
Decipher prescription instructions (b.i.d., p.o., PRN), laboratory diagnostic panels (CBC, HbA1c, eGFR), clinical acronyms (COPD, GERD, STEMI), and vital sign indicators.
Prescription & Dosage
t.i.d. (TID)
Ter in die (Three times a day)Take the medication three times during waking hours, typically every 8 hours.
Prescription & Dosage
q.i.d. (QID)
Quater in die (Four times a day)Take the medication four times daily, typically every 6 hours.
Prescription & Dosage
q.d. (QD)
Quaque die (Every day / Once daily)Take once each day at approximately the same time.
Prescription & Dosage
p.o. (PO)
Per os (By mouth / Orally)Indicates oral administration (swallowing tablets, capsules, or liquids).
Prescription & Dosage
PRN
Pro re nata (As needed / When necessary)Take only when symptoms arise (e.g., for pain, nausea, fever) within specified maximum limits.
Prescription & Dosage
stat
Statim (Immediately / At once)Indicates an urgent single dose required without delay.
Prescription & Dosage
a.c.
Ante cibum (Before meals)Take medication 30–60 minutes before eating.
Prescription & Dosage
p.c.
Post cibum (After meals)Take medication following a meal to reduce gastrointestinal irritation.
Prescription & Dosage
q.h.s. / h.s.
Hora somni (At bedtime)Take the medication in the evening right before sleep.
Prescription & Dosage
NPO
Nil per os (Nothing by mouth)Strict medical instruction withholding all food, fluids, and oral medications (common before surgery).
Prescription & Dosage
gtt
Guttae (Drops)Used for eye, ear, or nasal drop prescriptions.
Prescription & Dosage
IV
IntravenousMedication or fluids administered directly into a vein.
Prescription & Dosage
IM
IntramuscularInjected into muscle tissue (common for vaccines like Tdap, Hepatitis B).
Prescription & Dosage
SC / SubQ
SubcutaneousInjected into the fatty tissue just beneath the skin (e.g., Insulin, Low-molecular-weight heparin).
This information is educational only and does not replace professional medical advice.