body-container-line-1
27.10.2008 Feature Article

Taking The Right Dose

Taking The Right Dose
27.10.2008 LISTEN

Liza visited a pharmacy and made a health complaint. After asking a few questions, the pharmacist gave her a bottle (containing medicine) and said to her: 'Follow the label instructions accordingly.'

Liza returned to the pharmacy three days later and the following conversation ensued:

Liza: Good morning, sir. There's still no improvement in my condition.

Pharmacist: Did you take your medicine as I asked you to?

Liza: I did exactly what you asked me to do followed the label instructions! The label read: 'Keep tightly closed', and that's exactly what I did.

Obviously, this patient's condition did not improve simply because she didn't take her medicine. Ironically, she was following the instruction given by her pharmacist.

The label contained information including dosage instructions, storage instructions, batch number, manufacturing and expiry date etc.

 

In fact, the pharmacist had just handed on a silver platter, a reason for Liza (who dislikes taking medicine, especially bitter ones) not to take her medicine.

Of course the label clearly stated how Liza should take her medicine, but since she had been told to follow label instructions, she chose which instruction to follow.

 

What better choice could have been made by someone who dislikes taking medicines?

One of the serious errors that a dispenser (pharmacist, dispensing technician, nurse) can commit is 'to assume a patient knows what to do'. Guided by this assumption, we (pharmacists, dispensing technicians) often use how well dressed our patients are, as a measure of their knowledge. It is time we realised that 'outward looks are by no means mirrors of the brain'.

 

– Unfortunately, it is still common to see dosage instructions like '2 x 3' written on tablet/capsule envelopes.

 

A young man ended up in the hospital after taking 18 tablets of his medicine within a 24-hour period.

 

He took six tablets in the morning, took another six in the afternoon, and less than an hour after taking the final six tablets, he collapsed.

Investigations revealed he followed dosage instructions that read: '2 x 3'. Who are we (medical team) to blame him for such an interpretation?

 

After all, 'two times three' equals six! This was a clear case of negligence on the part of whoever dispensed the medicine to this young man.

 

Some medicine dispensers (especially those who are not professionals) are in this habit because they want to save time when writing dosage instructions on medicines.

 

Think again. What is our duty as health professionals? To save lives, or to save time?

Consider a typical verbal instruction like: 'two morning, two afternoon, two evening'.

Let's see what makes this instruction ambiguous. First, let's assume the medicine under discussion is in tablet form.

 

Tablets are formulated using technology that takes into consideration the means by which the drug will be introduced into the body.

 

Some tablets are designed to be chewed, others swallowed, sucked, placed under the tongue, etc.

Though they are all tablets, they have different properties. Chewing a tablet that is meant to be swallowed (and vice versa) can effect the action of the drug and for certain medicines, could expose you to harmful drug effects (eg. stomach irritation in the case of Diclofenac).

 

Therefore the above verbal instruction does not specify whether the patient should swallow, chew or suck the tablets.

Again, the terms morning, afternoon and evening are non-specific. Unless there is a consensus on which hour of the day refers to morning, afternoon, and evening, the presence of such words in any dosage instruction introduces ambiguity.

 

 The problem with giving instructions using these words (morning, afternoon, evening) is that it offers the patient an opportunity to exercise his or her discretion with regard to when to take his/her medication.

One patient may decide to take her medication at 10 a.m. (morning), 2 p.m. (afternoon) and 8 p.m. (evening); while another patient may take her medicine at 7a.m. (morning), 12 noon (afternoon) and 9:30 p.m. (evening).

 

Both patients have fully complied with their dosage instruction.

 

However, we observe that they took their medicine at different times. Also, for both patients, the dosage intervals (in hours) differed from one dose to another.

 

This brings to light one of the possible reasons for the varying responses to the same medicine, taken by different people.

Taking the right dose (e.g. one 500mg tablet) of a medicine, but disregarding its dosage interval, is as inappropriate as taking the wrong dose of a medicine and following its dosage interval.

Ideally, specific hours of the day must be stated when giving dosage instructions.

 

This, among other benefits, reduces the incidence of adverse effects/ side effects and reduces the likelihood of therapeutic failure [this is when a treatment regimen fails to achieve its intended purpose; or when the set objectives (of prescribers) that guide the prescribing process are not met].

 

Alternatively, the dispenser could specify the dosage interval (in hours), such as: 'every six hours', 'every eight hours', 'every 12 hours'.

 

However, it is always advisable for a dispenser (pharmacist, dispensing technician etc.) to design a dosage regimen which fully complies with the medicine's dosage interval, as well as complies with the patient's preferences regarding which hours of the day will be convenient for him or her.

Consider the phrases: 'before food' and 'after food', often used in giving dosage instructions.

Just like the above illustration, one can expect different patients (following the same ambiguous instruction) to take their medicine at different times of the day.

 

While some patients may take their medicine immediately after their last food bite, others may take theirs at times ranging from a few minutes to several hours 'after their last bite'.

 

Ironically, both groups would be complying with the instruction: 'after food'.

The rationale for such instructions — 'before food', 'after food' — is among other reasons, to prevent drug-food interactions, which may ultimately render the medicine ineffective.

Ideally, such a phrase must be qualified with a specific time/period. For instance, it is more appropriate to say and write 'one hour before food' instead of 'before food'; and 'two hours after food' instead of 'after food'.

 

The phrase must always be qualified with time (e.g. 30 minutes, one hour, two hours etc.) in order to eliminate ambiguity.

The above illustrations are not exhaustive. However, I have highlighted the commonest of these errors, with the aim of drawing the attention of health professionals to the effects of such acts of negligence; and cautioning the general public about one of the dangers of purchasing medicines from unauthorised persons and premises.

For most medicines, there is a thin line between efficacy, safety and toxicity. What actually makes any medicine 'good' is the information that accompanies it. Good (efficacious, safe) medicine dispensed with bad (wrong, inadequate, inaccurate) information will predictably result in bad (unwanted, harmful) effects and/or inefficacy.

I entreat all health professionals, especially pharmacists, to lay extra emphasis on giving accurate, unambiguous and comprehensible verbal dosage instructions, accompanied by clearly written (or printed) accurate, unambiguous and comprehensible labels.

Hopefully, the general public can now understand why it is extremely risky to purchase medicines from unauthorised (unprofessional) persons and from unauthorised premises such as buses.

 

You may just be missing the necessary information required to make your medicine safe and efficacious. Do not take your health for granted.

 

Discuss your health matters only with qualified people — preferably, a doctor, or a pharmacist.

Remember, 'your health is your wealth.'

By Samuel N. B. Poku-Bonsu

body-container-line