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Clinical pharmacology.

Why don't patients use medication as prescribed?

What does the term 'adherence' mean?

Adherence describes all aspects of how well or how poorly a patient follows a prescribed drug-dosing regimen or medical advice. Adherence is synonymous with synonymous with
adjective equivalent to, the same as, identical to, similar to, identified with, equal to, tantamount to, interchangeable with, one and the same as
 the old term 'compliance', but is preferred as it is more patient centred (compliance implies following orders). Adherence to therapy remains a challenge regardless of the patient's age, illness and social background. Health care providers initiate therapeutic regimens on the assumption that patients will take all their pills at the right time. Adherence is better with acute than chronic medication and tends to wane over time in cases of chronic disease. Even in the ideal circumstances of a randomised Adj. 1. randomised - set up or distributed in a deliberately random way

irregular - contrary to rule or accepted order or general practice; "irregular hiring practices"
 clinical trial, adherence to chronic medication is seldom more than 80%.

Patterns of non-adherence

Three major patterns of non-adherence are recognised: non-acceptance (the patient never actually starts treatment), incomplete execution (extra or missed doses, including 'drug holidays'), and early discontinuation dis·con·tin·u·a·tion  
A cessation; a discontinuance.

Noun 1. discontinuation - the act of discontinuing or breaking off; an interruption (temporary or permanent)
 (early cessation of dosing that is not resumed). Adherence is not limited to the number of doses taken every day, but also includes taking the dose at the right time or dosing interval dosing interval Therapeutics The frequency of intermittent drug administration, based on the drug's half-life. See Slow-release drug. . The most commonly observed deviations are missed or delayed doses. Taking drug holidays--the sudden cessation and resumption of dosing--is a potentially hazardous adherence behaviour. Restarting medications such as anti-arrhythmics (e.g. encainide or flecainide) or peripheral vasodilators Vasodilators Definition

Vasodilators are medicines that act directly on muscles in blood vessel walls to make blood vessels widen (dilate).

Vasodilators are used to treat high blood pressure (hypertension).
 without re-titration has resulted in lethal pro-arrhythmia or hypotension hypotension
 or low blood pressure

Condition in which blood pressure is abnormally low. It may result from reduced blood volume (e.g., from heavy bleeding or plasma loss after severe burns) or increased blood-vessel capacity (e.g., in syncope).
, respectively.

The consequences of poor adherence range from personal disability (treatment failure, e.g. ineffective pain control) to a worldwide threat (e.g. emergence of multidrug-resistant tuberculosis), depending on the illness, pattern of non-adherence and acceptable limits of the dosing interval (the degree of 'forgiveness' in the dosing regimen).

Why are patients non-adherent?

Adherence is a complex human behaviour and is influenced by the patient's personal and social characteristics. Health care facilities and prescribers can be barriers to adherence. Some common barriers to adherence are listed in Table I. Note that socio-economic status (except homelessness) and level of education are not barriers to adherence.

In his book, Improving Medication Adherence--How to Talk With Patients About Their Medication, Shawn Shea suggests three considerations in the decision to take medication:

1. feeling that there is something wrong

2. feeling motivated to try to get help through the use of medication

3. believing that the advantages of taking the medication will, in the long run, outweigh the disadvantages.

In addition, he suggests that there are three different beliefs that determine if a patient will start or stay on a medication:

1. efficacy of the medication

2. cost of the medication

3. psychological meaning of the medication.

If the health care worker does not address the above issues, then it is unlikely that the patient will adhere to adhere to
verb 1. follow, keep, maintain, respect, observe, be true, fulfil, obey, heed, keep to, abide by, be loyal, mind, be constant, be faithful

 the prescribed treatment.

How can adherence be measured?

A major problem in assessing adherence, both for individual patient care and research, is that a gold standard for measuring adherence has not been identified. Direct and indirect methods are used to monitor adherence, each with advantages and disadvantages (Table II).

Directly observed therapy directly observed therapy Therapeutics A strategy for ensuring Pt compliance with therapy, where a health care worker or designee watches the Pt swallow each dose of prescribed drugs. See Patient compliance. Cf Directed observation.  and measurement of drug concentrations (e.g. therapeutic drug monitoring therapeutic drug monitoring Clinical pharmacology The regular measurement of serum levels of drugs requiring close 'titration' of doses in order to ensure that there are sufficient levels in the blood to be therapeutically effective, while avoiding potentially ) are considered direct methods of measuring adherence, but are expensive and provider intensive. Directly observed therapy has been promoted by national tuberculosis programmes, but recent studies indicate that more patient-centered approaches are more successful than traditional clinic-based directly observed therapy. 'White coat' adherence, the phenomenon whereby patients increase adherence a few days before or after a consultation, is common. If the patient is taking a drug that is suitable for therapeutic drug monitoring, white coat adherence can result in drug concentrations being in the therapeutic range, thus masking mask·ing
1. The concealment or the screening of one sensory process or sensation by another.

2. An opaque covering used to camouflage the metal parts of a prosthesis.
 poor adherence. This is especially likely if the drug has a short half-life.

Methods to monitor adherence include self-report (asking patients about adherence or using questionnaires/medication diaries), caregiver/peer reports, assessing clinical response (e.g. correlating an outcome measure to adherence), pill counts, pharmacy refill refill noun A second allotment of a prescription agent obtained from a pharmacy, which is allowed by the original prescription verb Pharmacology To obtain more of a particular drug, after the initially prescribed amount of the agent has been used or  rates, and electronic medication monitors (electronic monitors that record the date and time of opening pill bottles or actuating ac·tu·ate  
tr.v. ac·tu·at·ed, ac·tu·at·ing, ac·tu·ates
1. To put into motion or action; activate: electrical relays that actuate the elevator's movements.


How can adherence be improved?

One of the problems in addressing poor adherence is that it can be difficult to distinguish different types of adherence behaviour. For example, 50% adherence can mean either a patient who follows the dosing instructions meticulously but stops completely halfway into treatment because of intolerable side-effects, or a patient who only takes half the number of pills every day to try to save money. The interventions required to improve adherence will be completely different in these two examples.

Several adherence interventions and combinations of interventions have been studied. The type of intervention will depend on the barrier(s) to adherence. Informational interventions aim to increase the provision and retention of treatment-related information (e.g. structured individual or group counselling or education by physicians, health educators, and/or pharmacists This is a list of notable pharmacists.
  • Dora Akunyili, Director General of National Agency for Food and Drug Administration and Control of Nigeria
  • Charles Alderton (1857 - 1941), American inventor the soft drink Dr Pepper
  • George F.
). The most common and effective behavioural Adj. 1. behavioural - of or relating to behavior; "behavioral sciences"
 interventions are simplifying dose regimens, specialised packaging, and cognitive behaviour therapy. Informational and behavioural interventions are often combined.

Interventions that are simple and easy to implement in practice are:

* Always make a point of checking patients' adherence. Doctors often overestimate o·ver·es·ti·mate  
tr.v. o·ver·es·ti·mat·ed, o·ver·es·ti·mat·ing, o·ver·es·ti·mates
1. To estimate too highly.

2. To esteem too greatly.
 patients' reported medication use. Patients like to please health care providers, and will report what they expect the health care provider would like to hear.

* Asking patients in a reassuring and non-judgemental manner if it has been difficult for them to take all their medications, and asking what you can do to help them not to miss doses.

* Asking patients about side-effects; this can also often unmask poor adherence.

* It is important to make the patient feel part of the therapeutic decision-making process.

* Always follow-up adherence interventions and reassess reassess

to reconsider the value or importance of

reassessment n

Verb 1. reassess - revise or renew one's assessment
 the patient's commitment/interest in the treatment plan.

What is the take-home message?

Patients' adherence to a prescribed regimen or medical advice is a complex behaviour. A patient's engagement with his/her illness, the prescribed drug regimen, the health care providers and health care facilities can all act as barriers to acceptable levels of adherence. Health care providers usually overestimate patients' reported medication use. Monitor for poor adherence in asymptomatic a·symp·to·mat·ic
Exhibiting or producing no symptoms.

Persons who carry a disease and are usually capable of transmitting the disease but, who do not exhibit symptoms of the disease are said to be
 diseases and when patients fail therapy despite an optimal dosing regimen.

C. Everett Koop Charles Everett Koop, (born October 14 1916 in Brooklyn, New York) is an American physician. He served as the Surgeon General of the United States from 1982 to 1989, under Ronald Reagan's presidency. , former Surgeon General The U.S. Surgeon General is charged with the protection and advancement of health in the United States. Since the 1960s the surgeon general has become a highly visible federal public health official, speaking out against known health risks such as tobacco use, and promoting disease  of the USA, is accredited accredited

recognition by an appropriate authority that the performance of a particular institution has satisfied a prestated set of criteria.

accredited herds
cattle herds which have achieved a low level of reactors to, e.g.
 with the following excellent advice: 'Drug's don't work in patients who don't take them'.

Recommended reading

Diiorio C, McCarty F, Depadilla L, et al. Adherence to antiretroviral antiretroviral /an·ti·ret·ro·vi·ral/ (-ret´ro-vi?ral) effective against retroviruses, or an agent with this quality.

 medication regimens: A test of a psychosocial psychosocial /psy·cho·so·cial/ (si?ko-so´shul) pertaining to or involving both psychic and social aspects.

Involving aspects of both social and psychological behavior.
 model. AIDS Behaviour 3 November 2007 (Epub ahead of print).

Osterberg L, Blaschke, T. Adherence to medication. N Engl J Med 2005; 353: 487-497.

Shea SC. Improving Medication Adherence: How to Talk With Patients About Their Medications. Philadelphia: Lippincott Williams & Wilkins, 2006.

Simoni JM, Montgomery A, Martin E, New M, Demas AD, Rana S. Adherence to antiretroviral therapy for pediatric pediatric /pe·di·at·ric/ (pe?de-at´rik) pertaining to the health of children.

Of or relating to pediatrics.
 HIV HIV (Human Immunodeficiency Virus), either of two closely related retroviruses that invade T-helper lymphocytes and are responsible for AIDS. There are two types of HIV: HIV-1 and HIV-2. HIV-1 is responsible for the vast majority of AIDS in the United States.  infection: a qualitative systematic review with recommendations for research and clinical management. Pediatrics 2007; 119(6): e1371-e1383. (Epub 28 May 2007, Review.)

Urquhart J, Vrijens B. Introduction to pharmionics: the vagaries in ambulatory Movable; revocable; subject to change; capable of alteration.

An ambulatory court was the former name of the Court of King's Bench in England. It would convene wherever the king who presided over it could be found, moving its location as the king moved.
 patients' adherence to prescribed drug dosing regimens, and some of their clinical and economic consequences. In: Mann RD, Andrews EB, eds. Pharmacovigilance. Chichester: John Wiley John Wiley may refer to:
  • John Wiley & Sons, publishing company
  • John C. Wiley, American ambassador
  • John D. Wiley, Chancellor of the University of Wisconsin-Madison
  • John M. Wiley (1846–1912), U.S.
 & Sons Ltd, 2007: 603-618.

JAN-STEFAN VAN DER DER - Distinguished Encoding Rules  WALT WALT World Association for Laser Therapy
WALT We Are Learning To (primary education)
WALT Warning Assessment Logic Terminal
WALT West's Automatic Law Terminal
, MB ChB

GARY MAARTENS, MB ChB, MMed, FCP (Fibre Channel Protocol) See Fibre Channel.

FCP - Flat Concurrent Prolog.

["Design and Implementation of Flat Concurrent Prolog", C. Mierowsky, TR CS84-21 Weizmann Inst, Dec 1984].


Division of Clinical Pharmacology Clinical pharmacology is the science of drugs and their clinical use. It is underpinned by the basic science of pharmacology, with added focus on the application of pharmacological principles and methods in the real world. , Department

of Medicine, University of Cape Town Coordinates:
“UCT” redirects here. For other uses, see UCT (disambiguation).
Table I. Common barriers to adherence to treatment for chronic

Patient characteristics
   Running out of pills
      Missed clinic appointments
      Poor access to pharmacy
   Other priorities (including financial commitments)
   Lack of information
      Lack of belief in benefit of treatment
      Lack of insight into the illness
      Not counselled in home language
   Psychological problems
     Active depression
     Substance abuse
     Cognitive impairment
     Lack of self-efficacy (the belief that a patient can execute a
     behaviour required to produce a certain outcome successfully)

Treatment/disease characteristics

   Treatment of asymptomatic diseases
   Side-effects of medication
   Complexity of treatment (e.g. dosing frequency, number of pills,
   food restrictions)
   Treatment regimen incompatible with patient's lifestyle/routine

Prescriber characteristics

   Poor knowledge of drug costs/medical-aid coverage
   Low level of job dissatisfaction
   Prescribing complex regimen
   Prescribing a regimen incompatible with the patient's lifestyle
   Poor therapeutic relationship

Health care system

   Missed appointments
   High health care costs (costs of drugs, co-payments, or both)
   Inability of patient to access the pharmacy
   Switching to a different formulary

Table II. Advantages and disadvantages of direct
and indirect adherence methods

Method                  Advantages              Disadvantages

Self-report             Inexpensive             Considerably
Caregiver report        Allows discussion       overestimates
(questioning            of reasons for low      adherence
patients                adherence
and completing

Clinical outcome        Inexpensive             Confounded by
(measuring drug         Allows discussion       factors other
effect, e.g.            of reasons for low      than non-adherence
[HbA.sub.1c]            adherence
in diabetics,
lipid profiles
for patients on
statins, viral
loads for patients

Pharmacy refill         Suitable for            Moderately
(rates of               individual patients     overestimates
refilling               as well as              adherence
prescriptions)          programmes              (more sensitive
                                                than pill counts)

Pill count              Inexpensive             Patients rapidly
(counting the number    Useful to detect        learn to provide
of pills remaining      misconceptions about    the correct number
in the patient's        dosing, especially      of pills
medication bottles      early on in therapy     (discarding unused
or vials)                                       doses/not returning
                                                unused medication)

                                                Time consuming


Therapeutic             Direct measure          Expensive
drug monitoring         Detection/prevention
(measuring drug         of drug toxicity,       Subject to 'white
and metabolite          especially in           coat' adherence
concentrations in       populations at          and may reflect
blood or urine)         risk (e.g. elderly,     only that the
                        children, pregnancy,    last dose
                        renal or liver          was taken
                                                Confounded by
                                                other causes
                                                of low

                                                May overestimate

Electronic              Provides data on        Expensive
medication monitoring   timing and
(electronic monitor     patterns of             Unable to detect
that records the date   missed doses            if patient
and time of opening                             takes wrong dose,
pill bottles,                                   or takes multiple
actuating canisters,                            doses out of
etc.)                                           container at the
                                                same time (e.g.
                                                taking morning
                                                and evening doses
                                                out simultaneously
                                                and putting the
                                                evening dose
                                                into a small
                                                pill box)

                                                May underestimate
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Author:Van der Walt, Jan-Stefan; Maartens, Gary
Publication:CME: Your SA Journal of CPD
Geographic Code:6SOUT
Date:Feb 1, 2008
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