Table Of ContentAnalytical Chemistry for Assessing
Medication Adherence
Emerging Issues in Analytical Chemistry
Series Editor
Brian F. Thomas
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Analytical Chemistry
for Assessing Medication
Adherence
Sangeeta Tanna
De Montfort University, Leicester, United Kingdom
Graham Lawson
De Montfort University, Leicester, United Kingdom
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BIOGRAPHIES
Sangeeta Tanna
Sangeeta Tanna has a PhD in Pharmaceutics and is a Reader in
Pharmaceutical Bioanalysis. Her expertise and research interests are
the bioanalysis and drug delivery fields. Her early research focused on
developing instrumental methods for measuring the glucose-dependent
delivery of insulin from a “smart” gel. This led to the development of
microanalytical methodologies for the determination of therapeutic
drugs from dried blood spots based on LC-MS, LC-MS/MS, and LC-
HRMS studies. Applications of this work to patient healthcare include
improved medications for newborn babies and to assess adherence to
cardiovascular drug therapy for adult patients. She has a track record
of published papers, invited international conference presentations,
grants, and awards for this research.
Graham Lawson
Graham Lawson has a PhD in Analytical Chemistry and has exper-
tise in instrumental analysis, in disparate areas such as environmental
exposure in the polymer industry, the identification of migrants from
food packaging, and factors influencing drug delivery and clinical
applications. The unifying themes are the detection of ultra-low levels
of contamination in complex matrices and the protection of people
from adverse exposures. He was co-opted onto a NATO special studies
group on the standoff detection of radiation. His current research
interests include novel analytical techniques applied to dried blood
spot analyses and to counterfeit drug detection.
PREFACE
This is a book about a problem, a worldwide problem, a problem that
needs the input from a disparate range of skills for a solution. The
problem is poor adherence to prescription medicines. The challenge for
the authors was to communicate the extent of the problem and the
efforts to overcome it in a way that is informative to everybody with
an interest in this situation.
In this book, the authors have attempted to capture a global per-
spective of the problem of nonadherence and to apply their bioanalyti-
cal and instrumental analytical chemistry expertise to considering
alternative objective but yet patient-friendly methods to assess individ-
ual adherence. This approach has proved to be a bigger challenge than
anticipated with a rapidly growing worldwide interest in this problem
becoming evident from public domain but not necessarily peer-
reviewed literature.
It is a simple fact that at least half of all prescription medicines may
be wasted because they are not taken as prescribed. Under these cir-
cumstances, patients get no benefit from their prescribed drug therapy
and billions of dollars are lost to the healthcare provider. In the cold
light of day, this seems an unrealistic situation—why should patients
suffer unnecessarily, why throw away such large sums of money? And
yet it happens. The pharmaceutical industry spends billions of dollars
on marketing its products but there are few examples of it helping peo-
ple to take them correctly. Healthcare professionals carry out patient-
centered checks on adherence, but in many cases, now accept that the
results will be optimistic. Patients present various reasons for not tak-
ing their prescribed medicines, many are understandable, even more
are not, but in most cases their clinicians are unaware of their actions.
Prescriptions are meant to achieve therapeutic levels of a particular
drug in a patient’s bloodstream. Analytical chemistry now has the
techniques to unequivocally measure these drug levels. Direct analysis
of blood or other biosamples can confirm that the clinician’s prescrip-
tion has achieved these levels, indicate patient adherence and identify
x Preface
any unexpected drug(cid:1)drug interaction or even an incorrect diagnosis.
This level of information is necessary because the therapeutic window
for some drugs is so narrow that if it is not achieved patient lives may
be at risk.
The book follows a logical sequence from an assessment of the
global problem of medicine nonadherence, in the chapter “Medication
Adherence,” to considering how noninvasive samples can be obtained
from a patient to assess the relevant drug levels. This approach, out-
lined in the chapter “Opportunities and Challenges for Analytical
Chemistry in the Assessment of Medication Adherence,” requires
knowledge of the factors affecting drug disposition in the body and
identifies both possible suitable biosamples and the anticipated drug
levels to be detected. Detection of the target drug presents analytical
chemistry with two challenges, namely specificity and sensitivity. Bio-
samples are complex mixtures, and the chapter “Analytical Chemistry
Methods for the Assessment of Medication Adherence” details the
different approaches taken to provide the specificity to ensure that only
the target species will be measured. Developing sufficient sensitivity is a
combination of sample size, drug concentration, and possibly sample
pre-work-up. Factors affecting sample throughput and some notional
instrumental comparisons are documented. The alternative approach
of measuring a disease symptom, as a measure of adherence, is also
considered. The complementary nature of both approaches is indicated
fromresultsfordifferentillnesses.
The authors accept that the chapter “Application of Bioanalytical
Methods to Assess Medication Adherence in Clinical Settings” probably
underrepresents all the work that is done worldwide to measure patient
sampledruglevelsandhenceassessadherencetomedication.Themissing
datawillbesharedbetweenhospitallaboratoriesandprivatehealthlabo-
ratories and is secured by patient confidentiality. Nevertheless, there is
sufficient material presented in the chapter “Application of Bioanalytical
MethodstoAssessMedicationAdherenceinClinicalSettings”todemon-
strate both international interest and collaboration in the direct assess-
ment of medication adherence in a wide range of illnesses. The chapter
“Medication Adherence: Where Do We Go From Here?” attempts to
bring together the problems perceived by different stakeholders in the
provision of the analytical services necessary to deliver a more objective
assessment of adherence and suggests some possible routes forward
Preface xi
including the concept of the attained drug level being a measure of
adherence rather than a determination of “when” or “if” the medication
wastaken.
Theauthorshopethatthisbookwillbeofinteresttoabroadreader-
ship audience including healthcare professionals; biomedical scientists;
analytical instrument manufacturers and users; sectors of the pharma-
ceutical industry; pharmacy, medical and biomedical students, and aca-
demics; researchers in drug analysis and related clinical chemistry
disciplines; regulatory bodies; government departments and policy-
makers for public health issues; patients and journalists with an interest
in public health issues; international public health agencies such as the
WorldHealthOrganization.
ACKNOWLEDGMENTS
We gratefully acknowledge Steve Lawson for production of most of the
images. We thank Carolyn Jones and Dr Elaine Woodland for proof-
reading the manuscript and for their valuable suggestions, without
which the manuscript would have been the poorer. Thank you Brian
for providing the opportunity and challenge to commit our thoughts
andideastopaper.
Sangeeta Tanna
Graham Lawson
11
CHAPTER
Medication Adherence
INTRODUCTION
Medicines are the most common intervention in healthcare and are
crucial in maintaining health, preventing illness, managing chronic
conditions, and curing disease. Getting the most from medicines for
both patients and health service providers is becoming increasingly
important as people are living longer and are suffering from more than
one long-term condition. Medicines are dispensed with the expectation
that they will be taken exactly as prescribed. However, their benefits
are often not realized because, alarmingly, only 50% of medicines pre-
scribed in developed countries are taken as recommended and this
figure is estimated to be lower in developing countries.1 In the words
of Dr C. Everett Koop, “drugs don’t work in patients who don’t take
them.”2 This lack of adherence to prescribed therapies is termed “med-
ication nonadherence” and is one of the most understated problems
facing healthcare systems worldwide.
WHAT IS MEDICATION ADHERENCE?
Adherence to (or compliance with) a medication regimen is generally
defined as the ability of a patient to take their medications in the way
recommended by their healthcare providers.1,2
The terms adherence and compliance are commonly used inter-
changeably to describe the extent to which a patient takes their
medication as prescribed.3 Compliance is defined as the extent to which
the patient’s behavior matches the prescriber’s recommendations.
Adherence in turn is the extent to which the patient’s behavior matches
the agreed recommendations from the prescriber. Their meanings
are, therefore, somewhat different since adherence presumes the
patient’s agreement with the recommendations, whereas compliance
suggests that a patient is passively following a doctor’s instructions,
rather than actively collaborating in the treatment process.3 Adherence
AnalyticalChemistryforAssessingMedicationAdherence.DOI:http://dx.doi.org/10.1016/B978-0-12-805463-5.00001-8
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