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), others are not. Thus, it is recommended that, as in PCF the following are written in full:

  • at bedtime
  • once daily
  • each morning
  • every other day
  • before food
  • after food
  • units (i.e. not U or IU).
Table 1  Abbreviations in PCF for drug administration times
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 

Because of widespread usage, the term ‘immediate-release’ is now used (without abbreviation) in PCF, rather than ‘normal-release’. For ‘slow-release’, ‘extended-release’ etc., ‘m/r’ (modified-release) is used generically.

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).
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
NHS not prescribable on NHS prescriptions
OTC over the counter (i.e. can be obtained without a prescription)
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
CI Confidence interval
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
ESRF End-Stage Renal Failure
FDA Food and Drug Administration (USA)
HR Hazard ratio
IASP International Association for the Study of Pain
MHRA Medicines and Healthcare products Regulatory Agency
N/A Not applicable
NICE National Institute for Health and Care Excellence
NPF Nurse Prescribers’ Formulary
NPSA National Patient Safety Association
NYHA New York Heart Association
(Not UK) Not commercially available in the United Kingdom
(Not USA) Not commercially available in the United States of America
OR Odds ratio
PCS/PCU palliative care service/unit
PI package insert (USA), equivalent to SPC
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

Receptor types

α1, α2 alpha adrenergic type 1, 2
β2 beta adrenergic type 2
δ delta-opioid
κ kappa-opioid
μ mu-opioid
5HT1A, 5HT2A 5-hydroxytryptamine (serotonin) type 1A, 2A etc. 
A1, A2, A2A  adenosine type 1, 2, 2A
CB1, CB2  cannabinoid type 1, 2
D2  dopamine type 2
GABAA, GABAB gamma-aminobutyric acid type A, B
H1, H2  histamine type 1, 2
M1, M2  muscarinic acetylcholine type 1, 2 etc.
MT1, MT2  melatonin type 1, 2
OPRL-1  opioid-related nociceptin receptor
SST1, SST2  somatostatin type 1,2 etc.
TRPV1  transient receptor potential vanilloid type 1

Ion channels

Cav   calcium
Kv   potassium
Nav   sodium


5HT 5-hydroxytryptamine (serotonin)
ACE angiotensin-converting enzyme
ADH antidiuretic hormone (vasopressin)
ALS amyotrophic lateral sclerosis
AMPA α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid
APTT activated partial thromboplastin time
ATP adenosine triphosphate
AUC area under the plasma concentration–time curve
CHF congestive heart failure
CKD chronic kidney disease
Cmax maximum plasma drug concentration
CNS central nervous system
COPD chronic obstructive pulmonary disease
COX cyclo-oxygenase; alternative, prostaglandin synthase
CrCl creatinine clearance
CRP C-reactive protein
CSF cerebrospinal fluid
CT computed tomography
CVS cardiovascular system
CYP450 cytochrome P450 enzyme pathway
DIC disseminated intravascular coagulation
DOAC direct oral anticoagulant
DVT deep vein thrombosis
ECG (EKG) electrocardiogram
eGFR formula-based estimation of glomerular filtration rate
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
GFR glomerular filtration rate
GI gastro-intestinal
Hb haemoglobin
HIV human immunodeficiency virus
Ig immunoglobulin
INR international normalized ratio
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
MND motor neurone disease
MRI magnetic resonance imaging
MSU mid-stream specimen of urine
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
NSCLC non-small-cell lung carcinoma
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
PEG percutaneous endoscopic gastrostomy
PG prostaglandin
PPI proton pump inhibitor
PT prothrombin time
RCT randomized controlled trial
RIMA reversible inhibitor of mono-amine oxidase type A
RTI respiratory tract infection
SaO2 oxygen saturation
SpO2 peripheral capillary 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)
h hour(s)
Hg mercury
kcal kilocalories
kg kilogram(s)
L litre(s)
mg milligram(s)
microL microlitre(s)
micromol micromole(s)
min minute(s)
mL millilitre(s)
mm millimetre(s)
mmol millimole(s)
mosmol milli-osmole(s)
msec millisecond
nm nanometre(s)
nmol nanomole(s)
sec second(s)

Updated August 2019