Pushing Pharmacy Towards Evidence-Based Practice

Today’s post is from a pharmacist who blogs under the pseudonym Avicenna, who looks at how to bring evidence to bear on decision-making. With this post Avicenna officially joins SBP as a contributor. Go check out his bio and his prior posts.

I am a community pharmacist who spends little time practicing evidence-based pharmacy. Most of my workday is devoted to medication distribution instead of medication management, patient care and education. Although I must say, I love being a community pharmacist with a passion and I’m glad that I chose this career. It’s incredibly fulfilling to realize that you’ve made a difference in a patient’s health, and being thanked for just doing your job.

When a someone asks me why they need a second medication to decrease their blood pressure, I must be ready to form a good answer. Part of what constitutes a good answer is if it is supported by evidence, while the rest is the result of counseling and communication skills. I need to emphasize the benefits and specify any harm of such therapy in a understandable way that relates to my patient. If I am limited in time but need to update my knowledge, I can offer my patient a callback when I’ll have done a bit of research. However, in order to increase my ability to find and use new evidence for my answer, I need to have a process to help me quickly locate and apply the latest studies. Evidence based practice is a process that deals with this important issue.

What is Evidence Based Practice?

Evidence based (EB) practice, in medicine or pharmacy, ”is the conscientious, explicit, and judicious use of current best evidence in making decisions about the care of individual patients”(1). It integrates the best science currently available with individual expertise of clinicians (physicians, pharmacists, nurses, etc.) while focusing on patients health outcomes, needs and preferences. It is important to use both expertise and evidence, since the former prevents us from being overwhelmed by inapplicable or inappropriate studies, while the latter assures us that our practice does not rapidly become outdated.

Importantly, EB practice is not a ”cookbook” or ”one size fits all” approach. It is ultimately a clinician’s own expertise that applies the best and relevant evidence to help each patient. This type of practice permits us to streamline clinical decision-making by using what’s been proven to work and to avoid what hasn’t been proven. It is not an evil ploy to prevent innovation, cut health care costs or limit medical freedom. Because it relies on real evidence, EB practice is the opposite of  “rules of thumb”, intuition, traditional remedies and pseudo-science.

Limitations to EB pharmacy

Usual barriers to adopting a more evidence-based pharmacy practice are becoming (slightly) less of a problem: recognition of professional (“cognitive”) services by patients and physicians; government incentive programs (e.g., medication history-taking and reviews); shifting of pharmacy administrative and technical tasks to pharmacy technicians; and availability of evidence-based references (e.g., Dynamed, ACP journal club, Clinical Evidence, Bandolier) have made it easier to adopt this type of practice.

However, limitations of EB practice include some significant barriers that are universal within the practices of medicine and pharmacy.(2) Health professionals often have to resolve situations for which there is no relevant evidence from clinical or basic research. However, the exponential growth in clinical research along with international efforts to identify, sort and rationalize the evidence will help to close the paucity of clinical studies. Difficulties in applying evidence, because of human biological variations and patient reluctance to use medications, make it hard to extrapolate and relate the evidence to individual patients. This has been partly resolved by incorporating specific trial methodologies (ie: sub-group analysis) and the use of numbers needed to treat (or harm) to relate statistics to patients in a way that is easily understandable. Also, the ever expanding demand for health care and the limited amount of resources have put pressures on professionals to treat more in less time.

Barriers unique to the practice of EB pharmacy include the need to develop literature searching and critical appraisal skills. Being able to read a trial and understand enough of the methodology and results to be able to criticize its limitations requires education and training. Finally, whether or not evidence-based practice improves medical outcomes is hard to quantify by randomized clinical trials, but there does exist research that say this type of practice improves outcomes (3,4,5). Even if physicians and pharmacists are required to do various clinical rotations and residencies throughout their education, there will always be enough gray area in medical decision-making to drive EB professionals to seek out new information.

The Evidence Based Practice Model

The process of evidence-based practice can be outlined by a 5-step model:

  1. Form a specific clinical question
  2. Search for the best evidence
  3. Critically appraise evidence for validity, clinical relevance and applicability
  4. Integrate the evidence with the patients clinical situation
  5. Evaluate the results

First, ask a Clinical Question

The focused clinical question formed must contain all the relevant information about a patient or clinical problem (P = patient characteristics, diagnosis, comorbidities, etc.), as well as a precise description of the intervention prescribed (I= medication, diagnostic tool, exposure), comparator (C= placebo, standard care, another intervention, etc.) and relevant outcomes (O= surrogate markers, morbidity, mortality, quality of life, symptoms, etc.). A good clinical question must be relevant to patient’s problem and thoughtful enough to make it easy enough to search the literature. A single sentence should highlight the important information about a patient and lead us to important medical outcomes to be managed by medication therapy. For example:


“In a 63 year old white female with uncontrolled hypertension (systolic HTN), controlled type 2 diabetes, and kidney damage (nephropathy) (P), which class of blood pressure lowering medication (I= ACE-inhibitor, or angiotension receptor blockers) is considered first-line therapy over other classes (C= beta blockers, calcium channel blockers, thiazide diuretics) to treat hypertension and prevent mortality, morbidity and kidney disease (O)?”

Search for the Evidence

The next step in EB practice is to search the literature for the latest evidence. Acquiring training in literature searching in medical school has been demonstrated to increase students’ abilities to retrieve quality evidence and the number of studies. (6,7) By improving efficiency with Pubmed and other databases, we can rapidly find relevant data. But relevant evidence isn’t just RCTs; it can also, in some clinical situations, come from clinical guidelines, secondary, or tertiary references (e.g., systematic reviews, critically appraised abstracts, and even textbooks).

Questions in areas of medicine that have a large pool of studies to support general interventions (as in PICO#1) can be usually be answered quickly by referring to the latest version of a guideline or textbook. However, for clinical questions that don’t have a large pool of studies or a guideline recommendation, health professionals are still challenged to quickly find the best evidence to guide their decision-making. Here is an example of a clinical question that may require a more thorough search:


“In a 62 year old white male with uncontrolled hypertension (systolic hypertension), despite taking a diuretic, at high risk of a heart attack and with chronic kidney disease (P), is a certain antihypertensive (I= ACE inhibitor and calcium channel blocker) combination better than another combination (C=ACE inhibitor and diuretic) in preventing mortality, morbidity and other related outcomes such as kidney disease (O)?”

By searching Pubmed using MESH terms and putting specific limits on the search (e.g., searches can be limited only to randomized clinical trials), one can find relevant data more quickly. (8) This is where training is important to easily and quickly find relevant evidence.

Critically Appraise the Evidence

Critical appraisal is the process of assessing and interpreting evidence by considering if a study has valid methodology, clinically significant results and is valid enough to use in a specific patient.
The usual mode of treatment in pharmacy is an intervention – a medication, typically. The ideal level of evidence needed to establish a treatment effect of an intervention is a randomized controlled trial (RCT). And with RCTs, the more the better.

Certain concepts of medical research are needed to fully appreciate the difference between a properly and a poorly done study. Randomization, proper control, blinding, inclusion-exclusion criteria, confounding factors, and statistical significance are all important concepts in clinical pharmacy research (Wikipedia gives a good overview). Health professionals that want to give evidence-based answers need to understand study types (e.g., cohort, case-control) and the strengths and weaknesses in these different study designs. To answer some types of questions (e.g., real-world adverse events) other study designs are almost always employed.

Within the last decade or so, many medical and pharmacy schools have added critical appraisal education to their curriculum. Even some continuing professional development programs have been funded to teach critical appraisal to professionals who want to learn this process. (9,10) There are now few barriers for health professionals interested in improving their practice.

Integrate the Evidence and Evaluate the Results

Here is where the practice of medicine becomes an art. Using all the hard data from our search and subsequent appraisal, we must answer the clinical question for patients that may or may fit the profile of a study’s inclusion criteria. We must then extrapolate the evidence to the clinician’s best judgment to evaluate if their patient should be expected to benefit from the intervention.

When a pecific question does not have robust data to support an intervention, clinicians may (cautiously) decide to form a decision on more basic science (e.g., animal studies, in-vitro studies, pharmacokinetic studies, etc.). For example, if a menopausal woman taking estrogen therapy wants to switch from tablets to an estrogen patch, pharmacists can use pharmacokinetic studies to estimate the appropriate patch dose that will relieve symptoms but not be expected to cause adverse effects. Laboratory values, symptoms, potential drug interactions, and other drug-related problems all come into play when evaluating the expected benefits and possible harms of a treatment.


The pharmacy profession continues to shift from being a dispenser of medication to a more active medication manager. Pharmacists are now required to make clinical decisions, (usually with a physician’s consent), that affect their patient’s medical care. Changing doses, therapeutic switches between medications, and and starting and stopping medication are all decisions that pharmacists make on a daily basis.

In an era where clinical evidence is growing exponentially, the pharmacist’s emerging role as a medication management expert requires a solid grounding in evidence-based practice. Training needs to start at the undergraduate level, and continue throughout a pharmacist’s education. (11)  But even for practicing pharmacists, short, intensive workshops can make a meaningful difference. (12) And when pharmacists practice in an evidence-based way, they can feel comfortable they’re bringing the best science to bear on pharmacy patient care.


1) Sackett DL et al., Evidence based medicine: what it is and what it isn’t., BMJ VOLUME 13 January 1996

2) Straus SE, McAlister FZ, Evidence-based medicine: a commentary on common criticisms, CMAJ, oct.3, 2000;163(7)

3) Fox CS, et al, Use of evidence-based therapies in short-term outcomes of ST-segment elevation myocardial infarction and non-ST-segment elevation myocardial infarction in patients with chronic kidney disease: a report from the National Cardiovascular Data Acute Coronary Treatment and Intervention Outcomes Network registry.  Circulation. 2010 Jan 26;121(3):357-65. Epub 2010 Jan 11.PMID: 20065168

4) Hoeks SE et al., Medication underuse during long-term follow-up in patients with peripheral arterial disease. Circ Cardiovasc Qual Outcomes. 2009 Jul;2(4):338-43. Epub 2009 Apr 24.PMID: 20031859

5) Timo E et al., Multifactorial Intervention to Prevent Recurrent Cardiovascular Events in Patients 75 years or Older: The Drugs and Evidence-Based Medicine in the Elderly (DEBATE) Study,American Heart Journal. 2006;152(3):585-592

6) Rosenberg WM, et al., Improving searching skills and evidence retrieval. J R Coll Physicians Lond. 1998 Nov-Dec;32(6):557-63

7) Schilling K, et. al., An interactive web-based curriculum on evidence-based medicine: design and effectiveness. Fam Med. 2006 Feb;38(2):126-32.

8 ) Pubmed Search: ((“Hypertension”[Mesh] AND “Kidney Diseases”[Mesh]) AND “Angiotensin-Converting Enzyme Inhibitors”[Mesh]) AND (“humans”[MeSH Terms] AND (Meta-Analysis[ptyp] OR Randomized Controlled Trial[ptyp]) AND English[lang] AND (“middle aged”[MeSH Terms] OR “aged”[MeSH Terms]) AND “2005/05/21″[PDat] : “2010/05/19″[PDat])

Relevant Study:Bakris GL, Sarafidis PA, Renal outcomes with different fixed-dose combination therapies in patients with hypertension at high risk for cardiovascular events (ACCOMPLISH): a prespecified secondary analysis of a randomised controlled trial, Lancet. 2010 Apr 3;375(9721):1173-81.
9)Continuing Pharmacy Education Online, College of Pharmacy Dalhousie University,Halifax, NS, Canada : http://cpe.pharmacy.dal.ca/PROGRAMS/Dal CPE Online/

10) CEBM.net : http://www.cebm.net/index.aspx?o=1732

11) Arri Coomarasamy et al., What is the evidence that postgraduate teaching in evidence based medicine changes anything? A systematic review BMJ 2004;329:1017 (30 October), doi:10.1136/bmj.329.7473.1017

12) Fritsche L, et al. Do short courses in evidence based medicine improve knowledge and skills? Validation of Berlin questionnaire and before and after study of courses in evidence based medicine
BMJ 2002;325:1338-1341 ( 7 December )

3 thoughts on “Pushing Pharmacy Towards Evidence-Based Practice

  1. Hi there,
    Great article on Evidence-Based Practice! I’m a 3rd year B.S.Pharm. student working for RxFiles in Saskatoon, SK this summer. RxFiles is made up of a group of pharmacists who publish evidence-based drug comparison charts for a variety of common conditions, which are designed to assist in the academic detailing sessions we also provide to physicians around the province. We operate as a not-for-profit organization on an arm’s-length grant from the SK government. Most importantly, WE DO NOT RECEIVE ANY INDUSTRY FUNDING OF ANY KIND. Please feel free to check out our website, which links to all of our charts, Newsletters, Q&A’s, and Major Trial Summaries. Thanks and keep up the great writing!

    Michael Hewitt

    “RxFiles – It’s All In The Details”

    • Despite the obvious and blatant advertisement, which is in violation with SBP’s commenting policy, I’ll let this go, simply because I like RxFiles.

  2. Even though a shameless plug, I’ll still take the compliment for the article, Michael! 😉

    I also like RxFiles as a quick reference guide and for its broad range of drug classes. I also like its evidence-based comparative charts coupled with solutions to some common drug related issues. As with any tertiary reference (textbook), it can become quickly outdated in some respects, but always a good reference to have on hand.

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