Safe prescribing

This is becoming an important issue, as evidenced by its increasing prominence in the undergraduate medical syllabus. Issues which need to be considered include^[1]:

• Prescribing within limits of competence.
• Evidence-based prescribing.
• Interaction with other drugs.
• Concordance, tolerability and formulation.
• Adverse effects.
• Checking dosages.
• Using prescribing formularies.
• Keeping up to date and following clinical guidelines, where available, from the National Institute for Health and Care Excellence (NICE) or Scottish Intercollegiate Guidelines Network (SIGN).
• Using electronic systems where available that can enhance the safety of prescribing.
• Responsible delegation of prescribing administration and dispensing.

Prescribing guidance

Writing prescriptions

Many prescriptions are now computer-produced but, if you are writing one by hand, write legibly in indelible ink, date the prescription and state the full name and address of the patient. All prescriptions should be signed by the prescriber. It is a legal requirement in the case of prescription-only medicines to state the age for children under 12 years, but it is good practice to do so in all cases. Other things to take care of include:

• Write generics unless there are bioavailability issues, as this will enable the pharmacist to dispense any suitable preparation, avoiding expense and delay.
• Avoid unnecessary use of decimal points (eg, 3 mg, not 3.0 mg). For quantities less than 1 gram, write in milligrams (eg, 500 mg, not 0.5 g). For quantities less than 1 milligram, write in micrograms (eg, 100 micrograms, not 0.1 mg). Don’t abbreviate micrograms, nanograms or units. Use millilitres (ml or mL) not cubic centimetres or cc.
• Schedules should be written in English, without abbreviation but some Latin abbreviations are acceptable. The British National Formulary (BNF) lists these in full, but common ones in use include:
  • stat = immediately.
  • p.r.n. = pro re nata = when required.
  • o.d. = omni die = every day.
  • o.n. = omni nocte = every night.
  • b.d. = bis die = twice daily.
  • t.d.s. = ter die sumendum = to be taken three times daily.
  • q.d.s. = quater die sumendum = to be taken four times daily.
• State minimum dose interval and maximum total amount when prescribing p.r.n items.
• The ‘number of days of treatment’ box can be used on NHS forms.
• Specify the strength and quantity. In the absence of this information the pharmacist will attempt to contact you. If unable to do so, they can use their discretion and professional judgement to dispense up to five days’ worth of treatment or appropriate amounts of combination packs or oral contraceptives. If they have insufficient information to make a judgement, they will return the prescription to you.
• Write on the prescription in inverted commas anything other than the name, strength and dosage of the tablets that you want to appear on the label – eg, ‘Sedative Tablets’.
• Avoid abbreviations of drug names and preparations as these can be misinterpreted – eg, Mist.Expect. Don’t invent compound generic names, especially for sustained-release preparations.

Computer-issued prescriptions

Recommendations include:

• Minimum data requirements:

• • Date.
  • Patient’s surname, one forename, other initials.
  • Address, title.
  • Date of birth.
  • The age of children under 12 years and of adults over 60 years must be printed in the box available; the age of children under 5 years should be printed in years and months.

• Doctor’s name must be printed at the bottom of the prescription form, surgery address, telephone number, reference number and primary care organisation. Prescriptions issued by GP registrars, assistants, locums, or deputising doctors should bear the name of a responsible principal.
• The prescription must be printed in English without abbreviation, the dose must be in numbers, the frequency in words, and the quantity in numbers in brackets (eg, 40 mg four times daily).
• All points about dose, frequency, strength, preparation, units above must be followed.
• Supplementary warnings or advice should be written in full.
• Handwritten alterations should only be made in exceptional circumstances and any alterations must be countersigned in the doctor’s own handwriting.
• Clearly mark duplicates as such.
• Unused space must be cancelled, or the end of the prescription indicated.