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Drug administration

In 2005, the Joint Commission on Accreditation of Healthcare Organizations (JCAHO) in the USA published National Patient Safety Goals. These include a series of recommendations about ways in which confusion (and thus errors) can be reduced by avoiding the use of certain abbreviations on prescriptions. The full set of recommendations is available at

Although some traditional abbreviations remain acceptable (e.g. Table 1), other commonly used ones are not. Thus, it is now recommended that the following are written in full:

  • at bedtime
  • once daily
  • each morning
  • every other day.

These four recommendations have also been adopted in PCF.

Although the following conventions have not been adopted in PCF, readers should be aware of the following recommendations for handwritten and printed prescriptions, and other printed medical matter, e.g. packaging, patient records:

  • include a space between the drug dose and the unit of measure, e.g. 25 mg, not 25mg
  • write 'per' instead of an oblique (mistaken for a figure 1), e.g. 200 mg per day, not 200mg/day
  • use 'subcut' or 'subcutaneous' instead of SC (mistaken for SL)
  • write 'less than' or 'greater than' instead of < and > (mistaken for a letter L or figure 7; or written the wrong way round and thus signifying the opposite of the intended meaning).

Further, although it has been recommended in the UK that ‘PR’ (prolonged-release) should become the generic term for ‘slow-release’, ‘extended-release’ etc., PR is a time-honoured abbreviation for ‘per rectum’. It is in this latter sense that PR will be used in PCF. As in earlier editions, ‘m/r’ (modified-release) will be used.

Note: in earlier editions, ‘normal-release’ was used for non-modified products. However, because of international popular usage, in this edition the term ‘immediate-release’ is used (without abbreviation).

Table 1    Abbreviations used in PCF for the times of drug administration
Twice per day b.d. bis die
Three times per day t.d.s. ter die sumendus
Four times per day q.d.s. quarta die sumendus
Every 4 hours etc. q4h quaque quarta hora
Rescue medication
(as needed/required)
p.r.n. pro re nata
Give immediately stat stat 
a.c. ante cibum (before food)
amp ampoule containing a single dose (cf. vial)
CD controlled drug; preparation subject to prescription requirements under the Misuse of Drugs Act (UK); for regulations see BNF
CIVI continuous intravenous infusion
CSCI continuous subcutaneous infusion
e/c enteric-coated (gastroresistant)
ED epidural
IM intramuscular
IT intrathecal
IV intravenous
IVI intravenous infusion
m/r modified-release; alternatives, controlled-release, extended-release, prolonged-release, slow-release, sustained-release
not prescribable on NHS prescriptions
OTC over the counter (i.e. can be obtained without a prescription)
p.c. post cibum (after food)
PO per os, by mouth
POM prescription-only medicine
PR per rectum
PV per vaginum
SC subcutaneous
SL sublingual
TD transdermal
TM transmucosal
vial sterile container with a rubber bung containing either a single or multiple doses (cf. amp)
WFI water for injections


* specialist use only
unauthorized (unlicensed) use
ACBS Advisory Committee on Boderline Substances
AHFS American Hospital Formulary Service
BNF British National Formulary
BP British Pharmacopoeia
CHM Commission on Human Medicines
CSM Committee on Safety of Medicines (now part of CHM)
DH Department of Health (UK)
EMEA European Medicines Agency
EORTC European Organisation for Research and Treatment of Cancer
FDA Food and Drug Administration (USA)
IASP International Association for the Study of Pain
MHRA Medicines and Healthcare products Regulatory Agency
NICE National Institute for Health and Care Excellence
NPF Nurse Prescribers’ Formulary
NPSA National Patient Safety Association
NYHA New York Heart Association
PCS/PCU palliative care service/unit
PEG percutaneous endoscopic gastrostomy
PIL Patient Information Leaflet (UK)
rINN recommended International Non-proprietary Name
RPS Royal Pharmaceutical Society
SIGN Scottish Intercollegiate Guidelines Network
SPC Summary of Product Characteristics (UK)
UK United Kingdom
UKMI UK Medicines Information
USA United States of America
USP United States Pharmacopoeia
VAS visual analogue scale, 0–100mm
WHO World Health Organization


ACE angiotensin-converting enzyme
ADH antidiuretic hormone (vasopressin)
AMPA α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid
ATP adenosine triphosphate
AUC area under the plasma concentration–time curve
β2 beta 2 adrenergic (receptor)
CHF congestive heart failure
Cmax maximum plasma drug concentration
CNS central nervous system
COX cyclo-oxygenase; alternative, prostaglandin synthase
COPD chronic obstructive pulmonary disease
CKD chronic kidney disease
CRP C-reactive protein
CSF cerebrospinal fluid
CT computed tomography
δ delta-opioid (receptor)
D2 dopamine type 2 (receptor)
DIC disseminated intravascular coagulation
DVT deep vein thrombosis
ECG (EKG) electrocardiogram
EFT enteral feeding tube
ERCP endoscopic retrograde cholangiopancreatography
FBC full blood count
FEV1 forced expiratory volume in 1 second
FRC functional residual capacity
FSH follicle-stimulating hormone
FVC forced vital capacity of lungs
GABA gamma-aminobutyric acid
GI gastro-intestinal
Hb haemoglobin
HIV human immunodeficiency virus
H1, H2 histamine type 1, type 2 (receptor)
Ig immunoglobulin
INR international normalized ratio
κ kappa-opioid (receptor)
LABA long-acting β2-adrenergic receptor agonist
LFTs liver function tests
LH luteinizing hormone
LMWH low molecular weight heparin
MAOI mono-amine oxidase inhibitor
MARI mono-amine re-uptake inhibitor
MRI magnetic resonance imaging
MSU mid-stream specimen of urine
μ mu-opioid (receptor)
NaSSA noradrenergic and specific serotoninergic antidepressant
NDRI noradrenaline (norepinephrine) and dopamine re-uptake inhibitor
NG nasogastric
NJ nasojejunal
NMDA N-methyl D-aspartate
NNH number needed to harm, i.e. the number of patients needed to be treated in order to harm one patient sufficiently to cause withdrawal from a drug trial
NNT number needed to treat, i.e. the number of patients needed to be treated in order to achieve 50% improvement in one patient compared with placebo
NO nitric oxide
NRI noradrenaline (norepinephrine) re-uptake inhibitor
NSAID non-steroidal anti-inflammatory drug
PaCO2 arterial partial pressure of carbon dioxide
PaO2 arterial partial pressure of oxygen
PCA patient-controlled analgesia
PE pulmonary embolus/embolism
PEF peak expiratory flow
PG prostaglandin
PPI proton pump inhibitor
RCT randomized controlled trial
RIMA reversible inhibitor of mono-amine oxidase type A
RTI respiratory tract infection
SaO2 oxygen saturation
SNRI serotonin and noradrenaline (norepinephrine) re-uptake inhibitor
SRE skeletal-related events
SSRI selective serotonin re-uptake inhibitor
TCA tricyclic antidepressant
TIBC total iron-binding capacity; alternative, plasma transferrin concentration
TlCO transfer factor of the lung for carbon monoxide
Tmax time to reach Cmax
UTI urinary tract infection
VEGF vascular endothelial growth factor
VIP vaso-active intestinal polypeptide
WBC white blood cell
w/v weight of solute (g) per 100mL


cm centimetre(s)
cps cycles per sec
dL decilitre(s)
g gram(s)
Gy Gray(s), a measure of radiation
h hour(s)
Hg mercury
kcal kilocalories
kg kilogram(s)
L litre(s)
mg milligram(s)
microL microlitre(s)
micromol micromole(s)
mL millilitre(s)
mm millimetre(s)
mmol millimole(s)
min minute(s)
mosmol milli-osmole(s)
msec millisecond
nm nanometre(s)
nmol nanomole(s); alternative, nM
sec second(s)