(1994; 115 pages) [French] [Spanish]
Chapter 9. STEP 4: Write a prescription
A prescription is an instruction from a prescriber to a dispenser. The prescriber is not always a doctor but can also be a paramedical worker, such as a medical assistant, a midwife or a nurse. The dispenser is not always a pharmacist, but can be a pharmacy technician, an assistant or a nurse. Every country has its own standards for the minimum information required for a prescription, and its own laws and regulations to define which drugs require a prescription and who is entitled to write it. Many countries have separate regulations for opiate prescriptions.
Information on a prescription
There is no global standard for prescriptions and every country has its own regulations. Do you know the legal requirements in your own country? The most important requirement is that the prescription be clear. It should be legible and indicate precisely what should be given. Few prescriptions are still written in Latin; the local language is preferred. If you include the following information, not much can go wrong.
Name and address of the prescriber, with telephone number (if possible)
This is usually pre-printed on the form. If the pharmacist has any questions about the prescription (s)he can easily contact the prescriber.
Date of the prescription
In many countries the validity of a prescription has no time limit, but in some countries pharmacists do not give out drugs on prescriptions older than three to six months. You should check the rules in your own country.
Name and strength of the drug
R/(not Rx) is derived from Recipe (Latin for ‘take’). After R/you should write the name of the drug and the strength. It is strongly recommended to use the generic (nonproprietary) name. This facilitates education and information. It means that you do not express an opinion about a particular brand of the drug, which may be unnecessarily expensive for the patient. It also enables the pharmacist to maintain a more limited stock of drugs, or dispense the cheapest drug. However, if there is a particular reason to prescribe a special brand, the trade name can be added. Some countries allow generic substitution by the pharmacist and require the addition ‘Do not substitute’ or ‘Dispense as written’ if that brand, and no other, is to be dispensed.
The strength of the drug indicates how many milligrams each tablet, suppository, or milliliter of fluid should contain. Internationally accepted abbreviations should be used: g for gram, ml for milliliter. Try to avoid decimals and, where necessary, write words in full to avoid misunderstanding. For example, write levothyroxin 50 micrograms, not 0.050 milligrams or 50 ug. Badly handwritten prescriptions can lead to mistakes, and it is the legal duty of the doctor to write legibly (Box 7). In prescriptions for controlled drugs or those with a potential for abuse it is safer to write the strength and total amount in words, to prevent tampering. Instructions for use must be clear and the maximum daily dose mentioned. Use indelible ink.
Box 7: Legal obligation to write clearly
Doctors are legally obliged to write clearly, as emphasized in the UK Court of Appeal ruling in the following case. A doctor had written a prescription for Amoxil tablets (amoxicillin). The pharmacist misread this and dispensed Daonil (glibenclamide) instead. The patient was not a diabetic and suffered permanent brain damage as a result of taking the drug.
The court indicated that a doctor owed a duty of care to a patient to write a prescription clearly and with sufficient legibility to allow for possible mistakes by a busy pharmacist. The court concluded that the word Amoxil on the prescription could have been read as Daonil. It found that the doctor had been in breach of his duty to write clearly and had been negligent. The court concluded that the doctor's negligence had contributed to the negligence of the pharmacist, although the greater proportion of the responsibility (75%) lay with the pharmacist.
On appeal the doctor argued that the word on the prescription standing on its own could reasonably have been read incorrectly but that various other aspects of the prescription should have alerted the pharmacist. The strength prescribed was appropriate for Amoxil but not for Daonil; the prescription was for Amoxil to be taken three times a day while Daonil was usually taken once a day; the prescription was for only seven days' treatment, which was unlikely for Daonil; and finally, all prescriptions of drugs for diabetes were free under the National Health Service but the patient did not claim free treatment for the drug. All of these factors should have raised doubts in the mind of the pharmacist and as a result he should have contacted the doctor. Therefore, the chain of causation from the doctor's bad handwriting to the eventual injury was broken.
This argument was rejected in the Court of Appeal. The implications of this ruling are that doctors are under a legal duty of care to write clearly, that is with sufficient legibility to allow for mistakes by others. When illegible handwriting results in a breach of that duty, causing personal injury, then the courts will be prepared to punish the careless by awarding sufficient damages. Liability does not end when the prescription leaves the doctor's consulting room. It may also be a cause of the negligence of others.
Source: J R Coll Gen Pract, 1989: 347-8
Dosage form and total amount
Only use standard abbreviations that will be known to the pharmacist.
Information for the package label
S stands for Signa (Latin for ‘write’). All information following the S or the word ‘Label’ should be copied by the pharmacist onto the label of the package. This includes how much of the drug is to be taken, how often, and any specific instructions and warnings. These should be given in lay language. Do not use abbreviations or statements like ‘as before’ or ‘as directed’. When stating ‘as required’, the maximum dose and minimum dose interval should be indicated. Certain instructions for the pharmacist, such as ‘Add 5 ml measuring spoon’ are written here, but of course are not copied onto the label.
Prescriber's initials or signature
Name and address of the patient; age (for children and elderly)
Box 8: Incomplete labels
The label on the drug package is very important for the patient as a reminder of the instructions for use. In many cases, however, labels are incomplete. An analysis of 1533 (=100%) labels showed:
No label or illegible
Quantity not recorded
No directions, or only ‘as before’/’as directed’
The data listed above are the core of every prescription. Additional information may be added, such as the type of health insurance the patient has. The layout of the prescription form and the period of validity may vary between countries. The number of drugs per prescription may be restricted. Some countries require prescriptions for opiates on a separate sheet. Hospitals often have their own standard prescription forms. As you can check for yourself, all prescriptions in this chapter include the basic information given above.
Exercise: Patients 29-32
Write a prescription for each of the following patients. Prescriptions are discussed below.
Boy, 5 years. Pneumonia with greenish sputum. Your P-drug is amoxicillin syrup.Patient 30:
Woman, 70 years. Moderate congestive cardiac failure. For several years on digoxin 0.25 mg 1 tablet daily. She phones to ask for a repeat prescription. As you have not seen her for some time you ask her to call. During the visit she complains of slight nausea and loss of appetite. No vomiting or diarrhoea. You suspect side effects of digoxin, and call her cardiologist. As she has an appointment with him next week, and he is very busy, he advises you to halve the dose until then.Patient 31:
Woman, 22 years. New patient. Migraine with increasingly frequent vomiting. Paracetamol no longer effective during attacks. You explain to her that the paracetamol does not work because she vomits the drug before it is absorbed. You prescribe paracetamol plus an anti-emetic suppository, metoclopramide, which she should take first, and wait 20-30 minutes before taking the paracetamol.Patient 32:
Man, 53 years. Terminal stage of pancreatic cancer, confined to bed at home. You visit him once a week. Today his wife calls and asks you to come earlier because he is in considerable pain. You go immediately. He has slept badly over the weekend and regular painkillers are not working. Together you decide to try morphine for a week. Making sure not to underdose him, you start with 10 mg every six hours, with 20 mg at night. He also has non-insulin dependent diabetes, so you add a refill for his tolbutamide.
There is nothing wrong with any of the four prescriptions (Figures 6, 7, 8 and 9). However, a few remarks can be made. Repeat prescriptions, such as the one for patient 30, are permitted. Many prescriptions are like that. But they also need your full attention. Do not write a repeat prescription automatically! Check how many times it has been repeated. Is it still effective? It is still safe? Does it still meet the original needs?
For the opiate for patient 32, the strength and the total amount have been written in words so they cannot easily be altered. The instructions are detailed and the maximum daily dose is mentioned. In some countries it is mandatory to write an opiate prescription on a separate prescription sheet.
A prescription should include:
* Name, address, telephone of prescriber
* Generic name of the drug, strength
* Dosage form, total amount
* Label: instructions, warnings
* Name, address, age of patient
* Signature or initials of prescriber
Figure 6: Prescription for patient 29
Figure 7: Prescription for patient 30
Figure 8: Prescription for patient 31
Figure 9: Prescription for patient 32