Principles and Practice of Pharmaceutical Medicine

27.10 Which forms of partial

compliance and

noncompliance are

particularly relevant?

White-coat compliance

The patient’s compliance in the observation
period is predominantly inadequate. A few days
prior to the consultation with his doctor, he
improves his compliance and with it also most of
the clinical parameters. This leads to the doctor
wrongly assuming that the patient’s long-term
treatment with the prescribed medication is
adequate.
A high blood pressure, for instance, can
become normal within a few days after regular
short-term treatment with many antihypertensive
agents. The regression of left ventricular hyper-
trophy (diminution of a dangerous increase of
the mass of heart muscle due to an illness) can
however only be achieved through regular intake
of the medication over a prolonged period of
time.

Drug holidays

This term implies that the patient discontinues the
intake of his medication for three or more conse-
cutive days. These so-called ‘drug holidays’ may
tend to occur on days on which the patient changes
his usual daily activities, that is chiefly at week-
ends, holidays and vacations.
Studies by Dr. W. Kruse and Prof. Dr. E. Weber,
Heidelberg, have shown that approximately 50%
of patients observed had at least one treatment-free
phase within a four weeks of treatment period.
According to these studies ‘drug holidays’ occu-
pied 15% of the entire observation period (Kruse
et al., 1990).
If a ‘drug holiday’ occurs shortly before a med-
ical consultation, the doctor may have the impres-
sion that his patient is not under satisfactory control
with the medication so far prescribed. The conse-
quence may be an increase in dosage or an unne-
cessary change of medication.

Skewed dosing

The statistical distribution of drug exposure among

ambulatory patients is strongly skewed downward,

with relatively little overdosing, but a great deal of

underdosing, relative to the prescribed dosing regi-

men. The consequences of this prevalent pattern of

drug exposure for treatment outcomes are product

specific.

Skipped dosing

The patient omits a scheduled dose. For example, if

the prescription is ‘twice daily’, the patient often

takes the medication once a day; if the recom-

mended dosage is one tablet daily, he often takes

one tablet every second day. Again, the conse-

quences of this frequent error are specific to each

pharmaceutical product, varying according to the

frequency and timing of skipped doses and the

products forgiveness.

Timing noncompliance

The daily intake of the medication is not at a

regular, set time but with large temporal deviations

or completely unstructured. This type of noncom-

pliance may fail to ensure adequate therapeutic

coverage, depending on the product’s forgiveness.

27.11 Actions to enhance

compliance and

persistence

The prevalence of suboptimal compliance in all

fields of chronic, ambulatory pharmacotherapy is

well established. This fact prompts the question:

How to insure good outcomes in a world of imper-

fect compliers? Also, there is the crucial question,

for chronic-use medicines: How long a patient will

continue to take the prescribed medicine?

Drugs can only exert their full benefit if they are

taken within certain limits of compliance with the

recommended regimen. These limits are, for most

27.11 ACTIONS TO ENHANCE COMPLIANCE AND PERSISTENCE 363