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236 April 2007 Family Medicine For the Office-based Teacher of Family Medicine William Huang, MD Feature Editor Editor’s Note: In this month’s column, Karl Iglar, MD; Natalie Kennie, PharmD; and Jana Bajcar, MScPharm, EdD, of St Michael’s Hospital and the University of Toronto, present the I Can PresCribE A Drug mnemonic, which summarizes the systematic approach to prescribing that they teach their residents. Office-based teachers can similarly use this approach to help residents and students select the most approprate medication for their patients. I welcome your comments about this feature, which is also published on the STFM Web site at www. stfm.org. I also encourage all predoctoral directors to make copies of this feature and distribute it to their preceptors (with the appropriate Family Medicine citation). Send your submissions to williamh@bcm. tmc.edu. William Huang, MD, Baylor College of Medicine, Department of Family and Community Medicine, 3701 Kirby, Suite 600, Houston, TX 77098-3926. 713-798-6271. Fax: 713-798-7789. Submissions should be no longer than 3–4 double-spaced pages. References can be used but are not required. Count each table or figure as one page of text. I Can PresCribE A Drug: Mnemonic-based Teaching of Rational Prescribing Karl Iglar, MD; Natalie Kennie, PharmD; Jana Bajcar, MScPharm, EdD Rational prescribing refers to the “selection of the most appropriate therapeutic regimen for a specific patient.”1 There is a need to teach learners principles of rational prescribing since one study found that medical students and residents often do not perform important tasks such as checking dosage calculations or searching for possible drug-drug interactions prior to writing a new prescription.2 Further, prescribing or prescription errors have been discovered in as many as 11% of all prescriptions in primary care.3 (Fam Med 2007;39(4):236-40.) From the Department of Family and Community Medicine, St. Michael’s Hospital, Toronto, and the Department of Family and Community Medicine (all) and the Leslie Dan Faculty of Pharmacy (Drs Kennie and Bajcar), University of Toronto. A previous survey found that only 38.5% of family medicine residency programs offered a formal pharmacotherapy curriculum.4 More recently, the Society of Teachers of Family Medicine Group on Pharmacotherapy has published guidelines for a pharmacotherapy curriculum that can be offered during family medicine residency training.5 Proper training in rational pharmacotherapy does result in rational prescribing habits, at least in the short term6 and therefore should be an integral part of residency curricula. Several systematic approaches to selection of pharmacotherapy have been described in the literature.7-9 The World Health Organization has published the Guide to Good Prescribing that promotes a global approach to rational prescribing.7 It includes creating a personal formulary of effective medications that are likely to be used frequently, defining the problem (diagnosis), specifying the therapeutic objective, ensuring that a medication from the personal formulary has proven efficacy and safety for the patient under consideration, informing the patient about the treatment, and then monitoring the results and stopping the drug when the problem has resolved. More recently, Bazaldua et al have incorporated these same principles including the consideration of nondrug therapy into the ESSEnCE approach to rational prescribing.8 In his description of a family medicine residency curriculum on prescribing, Gaspar lists efficacy, convenience, safety, and cost as “rational criteria” in choosing prescription drugs.9 Not surprisingly, various authors report similar components that are important in the rational prescribing process. For the Office-based Teacher of Family Medicine After focus groups of residents and faculty identified a need to develop a systematic approach to drug prescribing, the Family Medicine Residency Program of St. Michael’s Hospital, a fully-affiliated teaching institution within the University of Toronto, developed and adopted a formal curriculum in 2001 focusing on relevant pharmacotherapeutics knowledge and medication prescribing skills. Since then, through the therapeutics curriculum, residents have learned a systematic approach to prescribing, easily remembered by the mnemonic, I Can PresCribE A Drug, that isolates specific steps that lead to an individualized selection of a medication for a specific patient. This paper describes this approach and the related medication knowledge that the learner will need to consider at each step, which will ideally lead to the best medication being prescribed to a specific patient. This tool can be Vol. 39, No. 4 used by family medicine residents during their residency training as well as by medical students doing their clinical rotations. I Can PresCribE A Drug Mnemonic The mnemonic, comprised of seven components related to rational prescribing, starts with the learner creating a list of all potential pharmacotherapeutic and nondrug alternatives. This is followed by a sequence of steps that systematically eliminate or retain certain alternatives from the initial list. The end result is a selection of the best medication for a patient at a given time. Table 1 shows how this mnemonic can be applied to a specific patient situation and potential drug information resources that can be used or accessed by the learner to acquire the pharmacotherapeutic content for each step. 237 1. Indication The first step is to identify the diagnosis for the patient and decide if therapy is indicated. The learner must consider the general goals of therapy as well as the needs and expectations of the patient. The learner may access therapeutic information from clinical practice guidelines as well as other available evidence from clinical trials or systematic reviews. From this evidence, the learner identifies all potentially effective alternatives for therapy, both drug and nondrug, and learns if medication is indicated. 2. Contraindications The second step is to determine if any medications are absolutely contraindicated and thus need to be eliminated from the list of potential alternatives. This prompts the learner to consider drug allergies, Table 1 Use of the I Can PresCribE A Drug Mnemonic Case Scenario: Mrs DM, a 67-year-old woman (weight 70 kg, ideal body weight 65 kg), presents with poorly controlled diabetes mellitus (A1c 8.4%). She is currently treated with glyburide 10 mg by mouth twice per day. Her past medical history is significant for myocardial infarction complicated by congestive heart failure 1 year ago (symptoms now stable). Her medications include: glyburide 10 mg twice per day, gemfibrozil 600 mg twice per day, ramipril 10 mg once per day, aspirin 81 mg once per day, Furosemide 40 mg once per day. Mnemonic Components Indication I C a n Contraindications Case Example Description Treatment is indicated to achieve optimal control of glycemia of an A1c < 7%. In this case, the patient is currently taking glyburide at a maximum dose, and combination therapy is recommended from clinical practice guidelines, along with lifestyle changes. (Information such as this can be found in recent evidence-based clinical practice guidelines on diabetes mellitus.11-13 ) Potential therapeutic available alternatives to choose from include: • biguanides (eg, metformin) • glitazones (eg, pioglitazone, rosiglitazone) • α-glucosidase inhibitors (eg, acarbose) • insulin secretagogues (eg, nateglinide, repeglinide) • insulin Due to this patient’s history of congestive heart failure, one can eliminate glitazones as a potential choice.12,16,17 (continued on next page) Potential Resource Type • Evidence from clinical trials • Evidence-based clinical practice guidelines • Evidence from systematic reviews (including Cochrane reviews14 or Clinical Evidence reviews15) • Drug product monographs, including those from: • Published drug information references16-17 • Electronic drug information databases such as Epocrates®,18 Lexi-comp,19 and Micromedex® Healthcare Series20 238 April 2007 Family Medicine Table 1 (continued) Mnemonic Components Precautions P r e s C r i b E Case Example Description Pregnancy and lactation as a precaution is not applicable in this case. Potential Resource Type • Resources on medications during pregnancy and lactation (eg, Briggs et al. Laboratory indices that should be performed prior to drug therapy include Drugs in Pregnancy and Lactation21 ) a serum creatinine and liver enzymes. • Drug product monographs from published drug information references Potential drug-drug interactions should be considered. In this case, one or electronic drug information databases can eliminate repaglinide (a short-acting secretagogue) as a potential noted above choice, since when used in combination with gemfibrozil, it may cause • Drug interaction references including: 16,17 severe and prolonged hypoglycemia. • Published references22,23 • Electronic drug information databases18-20 Cost/ Compliance • Drug benefit or managed care In consulting drug benefit formularies, one may eliminate some alternatives due to their excessive cost. For example, acarbose and insulin formularies secretagogues may have limited coverage based on specific criteria. • Drug product monographs from published drug information references One may rule out the use of insulin at this stage since the need for or electronic drug information databases subcutaneous administration is inconvenient for the patient and has the noted above potential to lead to noncompliance. Efficacy One can rule out acarbose at this stage as it usually produces only a mean decrease in A1c of 0.5% to 0.8%, which is inadequate for this case scenario.12,13 Other oral hypoglycemic alternatives such as insulin secretagogues and metformin are likely to produce an average A1c lowering of 1.0% to 1.5%.12 Use of drug classes with similar mechanisms of action (eg, sulfonylureas and insulin secretagogues) is less effective than combination therapy with agents that have different mechanisms of action.13 For this reason, use of insulin secretagogues such as nateglinide can be ruled out at this stage. • Evidence from clinical trials • Evidence-based clinical practice guidelines • Evidence from systematic reviews (including Cochrane reviews14 or Clinical Evidence reviews15) Metformin, when used in obese patients, may improve cardiovascular outcomes, which would be of further benefit for this patient.24 At this stage, one realizes that metformin is a good option. Fasting blood glucose and A1c will need to be monitored to determine the effectiveness of drug therapy. Adverse effects A Potential common and serious side effects for potential treatment alternatives are considered, discussed with the patient, and monitored. For example, with metformin, a common side effect is gastrointestinal intolerance, while more-serious but rare side effects include hypoglycemia and lactic acidosis.16,17 • Drug product monographs from published drug information references or electronic drug information databases noted above • Adverse drug reaction reports (such as US Food and Drug Administration Safety Alerts25) Considering the step-wise process above, metformin is determined as the most appropriate alternative for this case, as other therapeutic alternatives have been ruled out. D r u g Dose/Duration/ Direction An appropriate starting dose for this patient would be metformin • Drug product monographs from published 500–1,000 mg orally each day and titrate by 500 mg increments every drug information references or electronic 7 days if home blood sugar readings remain high, to a maximal dose of drug information databases noted above 2,500 mg/day based on efficacy and tolerability.16,17 For the Office-based Teacher of Family Medicine major organ disease (eg, renal or hepatic, etc) or other concomitant disease in a given patient that would contraindicate the use of each therapeutic option. Drug product monographs that can be found in written references or electronic database products can be useful resources for this type of information. decision and what parameters will indicate that the therapy being considered is effective. On many occasions, the learner may also consult applicable evidence from clinical trials, systematic reviews, or clinical practice guidelines to ensure the most efficacious medication is chosen. 3. Precautions The evaluation of precautions has three distinct steps that may lead to further reducing the list of potential alternatives. First, the learner considers if the patient is pregnant or lactating. Second, the learner is asked to determine if there are any laboratory indices that need to be assessed prior to starting therapy to ensure that all potential precautions have been considered. Third, the learner considers the patient’s medical history and other drug therapy the patient may be taking to ascertain if there are any significant drug-disease or drugdrug interactions with the therapeutic option in question. Drug product monographs can be useful for this step as well as specialized resources on drug-drug interactions and the use of medications in pregnancy and lactation. 6. Adverse Drug Effects The learner then considers not only the common adverse drug reactions a patient may encounter as a result of the therapy but also the potentially serious side effects that could further influence the choice of drug therapy. Drug product monographs from written references or electronic databases are useful resources for this step. At this point in the stepwise process, the learner has narrowed down the choice to the best possible pharmacotherapeutic alternative and is ready to proceed with step 7. 4. Cost/Compliance This step prompts the learner to inquire about drug coverage the patient possesses and whether the therapeutic option is covered. The learner should also determine the cost of the medications being considered and consider which drug formulation allows for better compliance or easier administration, such as those that minimize the frequency of dosing. 5. Efficacy The learner now must consider the efficacy of treatment and compare the relative efficacy of the alternatives that remain as potential choices. In this step, the learner considers whether there are any patient-related factors relating to efficacy that could influence the 7. Dosage/Duration/Direction The learner must determine the appropriate dosage, duration of therapy, and any additional directions for the specific patient scenario. Drug product monographs from written references or electronic databases are potential resources for this step. Once the appropriate therapy is selected, the mnemonic can serve as a communication framework when discussing the rationale for therapy with a patient. Failure to consider or inform patients of important aspects of new medications, such as the name, purpose, adverse effects, and duration of therapy, may lead to nonadherence by the patient.10 Discussion Our I Can PresCribE A Drug approach is complementary to other approaches reported previously and provides an additional framework that learners can use to learn how to choose medications for individual patients. In addition Vol. 39, No. 4 239 to the key factors in medication selection reported by others,7-9 our approach emphasizes that learners consider all possible effective pharmacotherapeutic alternatives and also explicitly reminds them to address issues such as contraindications and precautions. By going through each step of this approach and including or excluding medications based on individual patient factors, the learner will arrive at the most suitable medication for the patient and also be able to explain to the patient why that medication was selected. The I Can PresCribE A Drug mnemonic has served as a useful framework for delivering a pharmacotherapeutics curriculum to family medicine residents at St. Michael’s Hospital, Toronto. When discussing specific patients and their need for drug therapy, office-based teachers of family medicine can use this approach to help students or residents learn how to select the most appropriate medication for the patient. Corresponding Author: Adress correspondence to Dr Iglar, 30 Bond Street, Toronto, Ontario M5B 1W8, Canada. 416-360- 4000, ext. 8013. Fax: 416-867-7498. [email protected]. REFERENCES 1. Knollmann BC, Smyth BJ, Garnett CE, et al. Personal digital assistant-based drug reference software as tools to improve rational prescribing: benchmark criteria and performance. Clin Pharmacol Ther 2005; 78(1):7-18. 2. Garbutt JM, Highstein G, Jeffe DB, Dunagan WC, Fraser VJ. Safe medication prescribing: training and experience of medical students and housestaff at a large teaching hospital. Acad Med 2005;80(6):594-9. 3. Sandars J, Esmail A. The frequency and nature of medical error in primary care: understanding the diversity across studies. Fam Pract 2003;20(3):231-6. 4. Dickerson LM, Denham AM, Lynch T. The state of clinical pharmacy practice in family practice residency programs. Fam Med 2002;34(9):653-7. 5. Bazaldua O, Ables AZ, Dickerson LM, et al. Suggested guidelines for pharmacotherapy curricula in family medicine residency training: recommendations from the Society of Teachers of Family Medicine Group on Pharmacotherapy. Fam Med 2005;37(2): 99-104. 240 April 2007 6. Karaalp A, Akici A, Kocabasoglu YE, Oktay S. What do graduates think about a 2-week rational pharmacotherapy course in the fifth year of medical education? Med Teach 2003; 25(5):515-21. 7. de Vries TPGM, Henning RH, Hogerzeil HV, Fresle DA. Guide to good prescribing: a practical manual. Geneva, Switzerland: World Health Organization, Action Programme on Essential Drugs, 1994. 8. Bazaldua O, Pollock M, Roaten S, Dobbie A. Teaching the ESSEnCE of office-based prescribing. Fam Med 2006;38(5):316-8. 9. Gaspar DL. Choosing prescription drugs rationally: a curriculum for a family practice residency program. Acad Med 1995;70(5):454-5. 10. Tarn DM, Heritage J, Paterniti DA, Hays RD, Kravitz RL, Wenger NS. Physician communication when prescribing new medications. Arch Intern Med 2006;166:1855-62. 11. American Diabetes Association. Standards of medical care in diabetes—2006. Diabetes Care 2006;29(suppl 1):S4-S42. 12. Canadian Diabetes Association Clinical Practice Guidelines Expert Committee. Canadian Diabetes Association 2003 Clinical Practice Guidelines for the Prevention and Management of Diabetes in Canada. Can J Diabetes 2003;27(suppl 2):S1-S140. Family Medicine 13. Nathan DM, Buse JB, Davidson MB, Heine RJ, Holman RR, Zinman SB. Management of hyperglycemia in type 2 diabetes. A consensus algorithm for the initiation and adjustment of therapy; a consensus statement from the American Diabetes Association and the European Association for the Study of Diabetes. Diabetologia 2006;49:1711-21. 14. The Cochrane Collaboration. Available at www.cochrane.org. Accessed November 16, 2006. 15. BMJ clinical evidence. Available at www. clinicalevidence.com. Accessed November 16, 2006. 16. Repchinsky C, ed. Compendium of pharmaceuticals and specialties. Ottawa, Ontario: Canadian Pharmacists Association, 2006. 17. Drug facts and comparison 2006, 60th edition. St Louis: Wolters Kluwer Health, Inc, 2005. 18. Epocrates®. Available at www.epocrates. com. Accessed November 16, 2006. 19. Lexi-Comp®. Available at www.lexi.com. Accessed November 16, 2006. 20. Micromedex® Healthcare Series. Available at www.micromedex.com/products/hcs. Accessed November 16, 2006. 21. Briggs GG, Freeman RK, Yaffe SJ. Drugs in pregnancy and lactation, seventh edition. Philadelphia: Lippincott Williams and Wilkins, 2005. 22. Hansten PD, Horn JR. Hansten and Horn’s drug interactions, analysis, and management (updated quarterly). St. Louis: Wolters Kluwer Health, Inc, 2006. 23. Tatro DS, ed. Drug interaction facts™ (updated quarterly). St. Louis: Wolters Kluwer Health, Inc, 2006 24. UK Prospective Diabetes Study Group. Effect of intensive blood-glucose control with metformin on complications in overweight patients with type 2 diabetes (UKPDS 34). Lancet 1998;352:854-65. 25. US Food and Drug Administration. Medical product safety information. Available at www.fda.gov/medwatch/safety.htm. Accessed November 16, 2006.