PRESCRIPTION WRITING - DOC

							                                                                                               1



                         PRESCRIPTION WRITING

This handout is divided into two parts:

 Regulation of Medicines

 Prescription Writing


                              Regulation of Medicines
Before a pharmaceutical company can sell a new medicine in NZ it needs the consent of
the Minister of Health. To obtain this it submits a registration dossier to the Therapeutics
Section of the Ministry of Health (also known as Medsafe).

The application is then considered by MAAC or the Medicines Assessment Advisory
Committee. Before applications for new medicines are submitted to regulatory bodies
the company usually completes trials on 1,000 to 3,000 subjects. MAAC has to consider
whether a medicine is of:
                              - proven efficacy
                              - acceptable safety

MAAC then makes a recommendation to the Minister of Health as to whether the
company should be allowed to market the medicine in NZ.

Datasheets for medicines that are registered in New Zealand can be obtained from the
Medsafe website which is www.medsafe.govt.nz

At the moment just because a medicine is registered in New Zealand it does not always
mean that it is registered in Australia. There are separate processes in the two countries
for the registration of new medicines. This is going to change and in the future there will
be a single process for registering medicines in Australia and New Zealand.

A parallel process occurs in other countries. In the US the agency responsible for
registration of medicines is the FDA or Food and Drug Administration.

If a medicine is registered for one indication and the company then wants to market the
medicine for a different indication they have to apply for this separately. For example
captopril was originally approved for the treatment of hypertension and heart failure.
Subsequently it became clear that it was also effective for the treatment of diabetic
nephropathy. The company, that manufactured captopril, sought and gained approval to
also market it for diabetic nephropathy.
                                                                                             2


Once a medicine is registered a doctor can prescribe the medicine for any indication that
they deem appropriate -
but the company can only promote a medicine to doctors for those indications that have
been approved by the Ministry of Health.



When a medicine is registered a decision is also made on its classification i.e. as a
                             - Prescription Medicine
                             - Over the Counter Medicine (OTC)

Prescription medicines can only be dispensed when a prescription has been written by a
doctor, midwife or dentist. (The law was amended to allow nurses, other than midwives,
to prescribe in defined areas such as child health but so far very few nurses have
completed the required training.)


OTC medicines do not require a prescription. They are divided into those:

- On General Sale e.g. aspirin or paracetamol.
  These medicines can be purchased in a supermarket.

- Pharmacy Only Medicines which can only be sold in a pharmacy e.g. econazole cream
  for use on the skin for treating fungal infections.

- Restricted Medicines. Although these medicines do not require a prescription they
  must be sold by a pharmacist and the sale recorded in a book e.g diclofenac tablets (this
  is to ensure it is not sold to someone with a contraindication such as peptic ulcer).

Most OTC medicines were initially available only as prescription medicines and they
became available as OTC medicines once they had been used for sometime and there
were no longer thought to be important concerns about their safety if sold directly to the
public.

Some medicines can be obtained both over the counter and on prescription e.g.
diclofenac.

If you wish to take diclofenac 25mg t.i.d. for 2 days it is cheaper and more convenient
(you don't have to see a doctor) to buy them over the counter. If on the other hand you
need to take 25mg t.i.d. for three months it is cheaper to go and see a GP even after you
pay the consultation fee.
                                                                                                 3


A contentious area is the regulation of herbal remedies that are sold by health food shops
and supermarkets as well as by pharmacies. Herbal remedies do not need go through the
same regulatory process as medicines provided they do not make therapeutic claims.
Companies making herbal remedies can make nonspecific claims such as "improves
vitality".

If however a therapeutic claim is made such as "relieves breathlessness and improves
lung function in patients with asthma" it becomes a medicine and cannot be sold until it
has been through the registration process.

A few years ago the Ministry of Health withdrew lyprinol (an extract of green lipped
muscle) from the market. It was being sold as herbal remedy but therapeutic claims were
made in advertising that it was effective in the treatment of cancer (even though there
was no evidence for this from clinical trials).



Once a medicine is registered it can be sold in New Zealand but this does not
automatically entitle it to a subsidy.
An example is Finasteride (trade names Proscar and Propecia). Finasteride is a 5
reductase inhibitor. It inhibits conversion of testosterone to dihydrotestosterone and is
used to treat benign prostatic hyperplasia and male pattern baldness (although it is not
dramatically effective for the latter indication).
It has been registered in NZ for some years but it has never been subsidised on the
pharmaceutical schedule. Any doctor can prescribe finasteride but the patient will have to
pay the full cost of about $80 per month.


Medicines that receive funding from the public purse go onto the Pharmaceutical
Schedule. The agency responsible for deciding if medicines go onto the Pharmaceutical
Schedule is Pharmac which is short for the Pharmaceutical Management Agency.


If a medicine is fully subsidised it does not mean that it is entirely free to the patient but
the only charge that the patient pays is the prescription charge.

Prescriptions are free for children under the age of six years.

Holders of Community Services Cards pay $3 per item.

Individuals with a High User Card (sees GP and/or hospital doctor 12 or more times in a
year) pay $3 per item.

Other individuals pay $15 per item (although there are an increasing number of other
exceptions – see below). If the item costs less than $15 the patient only pays the cost of
                                                                                             4


the item e.g. if a patient does not have a community services card they will only pay $5
for a salbutamol inhaler rather than paying a $15 prescription charge.

Once a family has collected 20 or more items in the course of one year, the prescription
charges fall to $2 per item.

Changes in the funding of primary health care are leading to changes in the prescription
charges. The $3 charge for prescriptions has been extended to everyone between 6 and 18
years of age and to everyone over the age of 65 years provided they are registered with a
Primary Healthcare Organisation (PHO). In addition patients who are registered with
practices where the majority of patients are in lower socio-economic groups (Access
Practices) also pay the lower prescription charge. Cheaper prescription charges will be
extended to other groups over the next few years.


Pharmac is concerned with how new medicines compare with the treatments that are
already available. They consider both efficacy and cost. Not surprisingly if they decide
that a new medicine is less effective and more expensive than the medicines that are
already available they are unlikely to fund it. There has been a great deal of controversy
about whether Pharmac is too slow to fund new medicines compared with other
developed countries.

There are a number of ways that the availability of a medicine can be restricted. This may
be done either because there are concerns that the medicine is expensive or because there
are concerns about the safe and appropriate use of a medicine if it is prescribed too
widely.

These strategies include:
                               -   Special Authority
                               -   Specialist Prescriptions
                               -   Part Charges

A Special Authority means that there are specified criteria that have to be met before a
medicine can be prescribed. The doctor has to complete a form indicating that the patient
meets these criteria. The form is then faxed or mailed to Health Benefits Limited in
Wanganui.
If the form is filled in correctly and the patient meets the criteria the patient is given a
special authority number e.g. CHEM/00012345/May 2005
This number has to be written on each prescription for the medicine if the patient is to
receive the subsidy.

An example of a medicine that requires a special authority is salmeterol which is a long
acting inhaled beta agonist.
The criteria is that the patient:
- has asthma
- uses 1500mcg /day of beclomethasone (or equivalent dose of other inhaled steroids)
                                                                                             5


- the asthma is uncontrolled
-they are unable to tolerate eformoterol

This is purely a cost saving measure since eformoterol which is another LABA that is no
or more less safe or effective can be prescribed without special authority.

Special Authority Forms can be downloaded from www.pharmac.govt.nz
Some medicines can only be prescribed by the appropriate specialist. An example is
amiodarone which can only be prescribed by physicians. This is a safety issue rather
than a cost issue because amiodarone is associated with many adverse effects such as:
                              - torsades de pointes
                              - interstitial lung disease
                              - peripheral neuropathy
                              - hepatic steatonecrosis
                              - photosensitivity
                              - hyper or hypothyroidism

The use of this medicine should be closely monitored by someone who has experience of
using it. Like most specialist medicines, other doctors can write prescriptions for it
provided the appropriate specialist (in this case a physician) has recommended it. If a
physician initiates treatment with amiodarone, a GP can continue the treatment by writing
a prescription that says "Recommended by Dr (name of specialist)".


A Part Charge is where a medicine is partly subsidised and the patient has to pay an
additional charge in addition to the standard prescription charge (but they still pay less
than the full cost of the medicine). Pharmac is not keen on part charges and is phasing
them out.
                                                                                            6




                                 Prescription Writing


There are a number of requirements that need to be fulfilled for a prescription to be legal.
It is important to be aware of these.


IT IS ESSENTIAL THAT THE PRESCRIPTION IS LEGIBLE.

Ideally the prescription should be printed to increase legibility.

There are many horror stories of the consequences of not writing prescriptions legibly.

One much cited example that occurred in this city was when a patient was prescribed
chlorpromazine ( a neuroleptic). The prescription was not written legibly, the pharmacist
dispensed chlorpropamide (an oral hypoglycaemic) and the patient died of
hypoglycaemia.


The name (surname and initials), address and registration number of the doctor needs
to be clearly identified on the prescription form.

The name of the doctor should be printed at the top of the form along with his or her
Medical Council Number and the Doctor's address.
Ideally the Doctor's phone number should be provided on the prescription form in case
the pharmacist needs to contact them. Hospital doctors should consider providing an
extension or locator number in addition to the phone number of the hospital.

The name and full residential address of the patient has to be recorded on the
prescription (a PO Box number is not adequate). If the patient is under 13 years of age
their date of birth also has to be recorded on the prescription.

There is provision on the prescription form to record the patients code for prescription
charges:

A = adult
J = under 16 years
Y = under 6 years
O = prescription for oral contraceptive

1 = Community Services Card
3 = Others

Z = High User Card
                                                                                            7




Each prescription has three parts.


The first part of the prescription is where lists
                               - the name of the medicine
                               - the formulation e.g. caps, tabs, syrup etc
                               - the strength of the medicine

Traditionally this portion begins with the symbol Rx which is short for the Latin "Recipe"
which translates as "Take thou"

If the prescription is for amoxicillin this portion might read:

Rx Amoxicillin caps 250mg




Alternatively if the prescription is for a child the prescription might read:

Rx Amoxicillin syrup 125mg/5ml

Although the use of Rx is hallowed by tradition it is not a legal requirement. It is
sufficient to write:
Amoxicillin caps 250mg or Amoxicillin syrup 125mg/5ml.
The second part of the prescription is the instructions for the patient that go on the label.

Traditionally this begins with the abbreviation Sig . This is short for Signa which means
mark or write. (Again it does not invalidate the prescription if you omit Sig).

In the case of amoxicillin the second section of the prescription may be written as:

Sig: i t.i.d or Sig: i t.i.d p.o.

This will be written on the label as "Take one capsule three times a day" or " Take one
capsule three times a day by mouth".

The bioavailability of amoxicillin is greater with food so the pharmacist may write on the
label: "Take one capsule three times a day with food".

One does not need to limit one's instructions to something as brief as: i t.i.d.
If you want more detailed instructions to be written on the label you can specify this.
Etidronate, a bisphosphonate used for the treatment of osteoporosis, is an example of this.
                                                                                              8


Etidronate is taken cyclically for 2 weeks every three months and has to be taken on an
empty stomach because of its poor bioavailability. You could give the patient separate
written instructions about this.
Alternatively you could write the prescription so that the information was on the label i.e
Sig: 2 tabs with a glass of water in the morning an hour before food while upright. Take
for the first two weeks of every three months.

When it comes to writing this part of the prescription there are a number of other
abbreviations that you need to be aware of. These include:

o.d.           once daily
b.i.d.         twice daily
t.d.s.         three times daily
q.i.d.         four times daily

p.o.           orally
p.r.           rectally
s.c.           subcutaneously
i.m.           intramuscularly
i.v.           intravenously
s.l.           sublingual
p.r.n.         as required
a.c.           before food
p.c.           after food


The third part of the prescription tells the pharmacist how much to dispense.
Traditionally this is preceded by the symbol M which is an abbreviation of the Latin
Mitte (again it does not invalidate the prescription if you omit M).

If you wanted to calculate the number of capsules for amoxicillin 250mg t.d.s. for 5 days
it would be:
M: 15 caps

On the other hand it is simpler and less prone to error if you simply write:
M: 5 days supply
and you leave the pharmacist to calculate the number of capsules to be dispensed.


The maximum that can be dispensed on a single prescription is 3 months supply except
for oral contraceptives where it is 6 months.

Until recently most medicines were dispensed as one months supply at a time. This meant
that even if you wrote a prescription for three months supply the patient would have to
return to the pharmacy each month to pick up the next months supply.
                                                                                             9


This was recently changed and now for most medicines three months supply will be
dispensed all at once.

There are however some medicines that are still only dispensed in one month quantities
because they are expensive and there are concerns about wastage if the patient stops
taking the medicine.

The doctor still has the option of asking for a medicine to be dispensed more frequently
than once very three months.

This could be because of concerns about safety. It may not be appropriate to give a
patient a three month supply of tricyclic antidepressants if they are deemed to be at high
risk of taking an overdose.

Alternatively there may be issues of compliance. Because of problems with compliance
some patients have their medicines dispensed in blister packs and they may collect a
new blister pack every fortnight.

If the medicine is to be dispensed less often than every three months the prescription
should be annotated as Close Control or CC and the prescriber should specify how often
the medicine should be dispensed.
The bottom of the prescription must be signed by the doctor in his or her own hand.

The prescription must also be dated.


Trainee Interns cannot sign prescriptions. (They can write the rest of the prescription
out but a registered medical practitioner must check the prescription and then sign it).

First Year House-Officers can only write prescriptions for hospital patients using
hospital letterhead. You ae not allowed to write prescriptions outside hospital until you
are fully registered.


Controlled Medicines

Prescriptions for medicines that have been classified as Class A, Class B or Class C4
controlled medicines have to be written on a special triplicate Controlled Drugs
Prescription Form.

An example of medicine where you need this form is morphine.

In hospital these prescription forms are kept under lock and key.

The patient details have to be written by hand – a sticker is not acceptable.
                                                                                         10


One cannot provide more than 30 days supply per prescription and no more than 10 days
supply will be dispensed by the pharmacist at one time.

The patient presents all three copies of the prescription to the pharmacy and has to do so
within 8 days of the prescription being written. (Other prescriptions can be presented up
to 6 months later).

Unregistered Medicines

There is provision under Section 29 of the Medicines Act for a doctor to obtain an
unregistered medicine to treat a named patient.

Details of any patient treated with an unregistered medicine have to be forwarded to the
Ministry of Health. If a patient suffers an adverse event with an unregistered the medical
liability is unclear (ACC do not accept responsibility) and on occasion it may be
advisable to get a patient to sign a consent form when using an unregistered medicine.

Unregistered medicines are also used in clinical trials. Before an unregistered medicine is
used in a clinical trail the study has to be approved by the Standing Committee on
Therapeutic Trials (SCOTT).