Patient Safety Tip of the Week


April 12, 2011

Medication Issues in the Ambulatory Setting



Acute care settings have dominated the literature on patient safety. But there are significant patient safety issues on the ambulatory care side as well. Probably the four most common safety issues in ambulatory care are (1) diagnostic errors (2) medication errors (3) failure to follow up on test results and (4) missed opportunities to prepare patients for hospitalizations.


But medication errors are both frequent occurrences in the ambulatory setting and perhaps most amenable to improvement. One of the earliest studies on the frequency and impact of drug complications in outpatients (Gandhi 2000) found that 18% of outpatients responding to surveys reported a drug complication but that chart review found documentation of the event in only 3%. Number of medical problems, failure to explain side effects, and language other than English or Spanish were factors associated with drug complications. Almost half those with complications sought medical attention and 5% required hospitalization. 13% had a documented previous reaction to the offending drug. The occurrence of a drug complication also impacted negatively on patient satisfaction.


The same group later did a prospective cohort study (Gandhi 2003) in ambulatory practices and found 25% of outpatients had adverse drug events, 13% of which were serious. They found 28% of the events were ameliorable and 11% preventable. Number of medications was significantly associated with adverse events. Drug classes most often involved were SSRI’s, beta blockers, ACE inhibitors, and NSAID’s. Significantly, physician failure to respond to medication-related symptoms was notetd in 63% of the ameliorable adverse events and in 37% the patient failed to inform the physician of the symptoms. Most of the errors occurred in the prescribing or monitoring phases. They also noted that many of the events could be potentially preventable using computerized medication prescribing using clinical decision support tools.


An even later study by the same group (Gandhi 2005) showed that basic computerized prescribing systems may not be adequate to prevent serious medication adverse events and that more advanced systems using clinical decision support tools (like dose and frequency checking) are likely necessary to improve patient safety. The theoretical potential impact of medication safety alerts on medication safety and healthcare utilization is substantial (Weingart 2009a) but in practice most physicians override such safety alerts in currently implemented systems (Isaac 2009). Hence, avoid alert fatigue by using alerts for just the most important safety issues and consider making those “hard” alerts that cannot be easily overridden.


A study done on ambulatory patients aged 65 and older (Gurwitz 2003) found a rate of 5% per year of adverse drug events. This study used a variety of methods to detect the adverse events but did not directly contact the patients. The higher rates in the Gandhi studies suggests that chart-based methods are likely to significantly underestimate the frequency of adverse drug events. Almost 28% of the events were considered potentially preventable. Problems in the prescribing and monitoring phases were most common and problems with patient adherence were also significant.


Compared to the offending drugs in inpatient adverse drug events (which involve more often insulin, anticoagulants, narcotics, sedative/hypnotics, and chemotherapy), those in the ambulatory setting more often involve antidepressants, antihypertensive medications, cardiovascular medications, hypoglycemic agents, and non-opioid analgesics. However, keep in mind that the above studies were done prior to the recent surge in use of narcotic analgesics, particularly the longer-acting ones, that may be associated with adverse events (Bohnert 2011, Cohen 2010). And don’t forget that many of the hospitalizations result from adverse events related to anticoagulants.


Just as importantly though, many of the inpatient adverse drug events are related to confusion regarding medications originally presecribed on outpatients. Insulin is the classic drug in the regard. In fact, in the UK there has been a recent emphasis on using “insulin passports” to help avoid such problems when patients get admitted (NPSA 2011). The actual passport is a foldable medication list that the patient can carry in a wallet or purse. There is also a separate information booklet for patients describing what questions they should be asking when admitted to the hospital. You can also use patient medication tools like the Massachusetts Coalition for the Prevention of Medical Errors Patient Med List or the AHRQ411 “How to Create a Pill Card”.


The mechanics of the drug prescription are also important. Even when we are doing what we think may be the safest practices, we must be wary of unintended consequences. For example, as neurologists we often prescribe anticonvulsants “daw” (dispense as written) so that the patient always gets a brand name rather than a generic equivalent. That is not because we think the brand name is any better than the generic. It is simply that the bioavailability may differ from one generic manufacturer to another. Patients always given the anticonvulsant from the same generic manufacturer do usually achieve stable blood levels. However, if the pharmacy switches manufacturers, the blood levels may change and a patient may end up below or above the desired therapeutic range. So many of us use the “daw” to ensure that a drug from the same manufacturer is dispensed each time. However, recently a paper looked at the consequences of “daw” prescribing and found that a much higher percentage of patients are not adherent when their medications are dispensed “daw” – another unintended consequence of what we thought was the safest procedure!


And how you tell patients to take their meds (the “sig:” on your prescriptions) is also critical. A recent study (Wolf 2011) gave well-educated volunteers prescriptions for seven drugs and watched them try to figure out how and when to take them all. They could theoretically be consolidated to be taken in 4 dosing sets per day. Yet only 15% were able to consolidate the regimen to 4 times daily or less. Most ended up with regimens taking medications 6 or 7 times daily. Even the instructions “twice daily” and “every 12 hours” resulted in medications being taken at different times.


There is also often a disparity between what the physician thinks the patient is taking and what the patient is actually taking. In one study (Schillinger 2005) 50% of patients reported taking warfarin doses that were discordant with what the physician reported, often resulting in either over- or under-anticoagulation.


And don’t forget to avoid dangerous abbreviations. Use ISMP’s expanded list of “Do Not Use” abbreviations rather than the shorter “Joint Commission” minimal list used by most hospitals (see our July 14, 2009 Patient Safety Tip of the Week “Is Your “Do Not Use” Abbreviations List Adequate?”). Remember that any abbreviation you use in your prescriptions, lists or medical records has a chance of being copied into an order or medical record in a hospital or other setting. Interestingly, in some settings computerized alerts have helped reduce use of dangerous abbreviations (Myers 2011).



We’ve also done several columns on medication errors in other ambulatory settings (see our Patient Safety Tips of the Week for June 12, 2007 “Medication-Related Issues in Ambulatory Surgery”, August 14, 2007 “More Medication-Related Issues in Ambulatory Surgery”, March 24, 2009 “Medication Errors in the OR”, October 16, 2007” Radiology as a Site at High-Risk for Medication Errors). And, of course, we’ve done numerous columns on Beers’ List of potentially inappropriate medications in the elderly (see our January 15, 2008 Patient Safety Tip of the Week “Managing Dangerous Medications in the Elderly“ and our What’s New in the Patient Safety World columns for June 2008  Potentially Inappropriate Medication Use in Elderly Hospitalized Patients” and September 2010 “Beers List and CPOE” and October 19, 2010” Optimizing Medications in the Elderly”).



So what should you be doing?

·        Use electronic prescribing with clinical decision support tools

·        Discuss with patients what side effects to watch for and when to call when prescribing new medications

·        Develop medication-specific checklists to go over on return visits after initiating new medications

·        Utilize other healthcare workers (pharmacists, nurses, advanced practice nurses, etc.) to contact patients after new medications are begun

·        Improve medication reconciliation in both directions with hospitals (and other levels of care)

·        Focus on improving patient adherence with medication regimens

·        Avoid dangerous abbreviations in prescribing medications (and use the ISMP list, not the short “Joint Commission” list)

·        Always consider a patient’s resources (eg. financial, caregiver, etc.) in prescribing medications

·        Make medication instructions as simple as possible yet be explicit (and be sure the patient clearly understands how the drug is to be taken)

·        Always consider any potential language barriers and the health literacy of the patient in understanding medications

·        For those drugs requiring monitoring, build alerts and reminders into your system (whether your system is electronic or paper-based)

·        Consider using “insulin passports” or any of several readily available patient medication lists for patients to keep with them at all times

·        Think twice when prescribing “d a w” (dispense as written)







Gandhi TK, Burstin HR, Cook EF, et al. Drug complications in outpatients.

J Gen Intern Med. 2000; 15(3): 149-154



Gandhi TK, Weingart SN, Borus J, et al. Adverse Drug Events in Ambulatory Care.

N Engl J Med 2003; 348: 1556-1564



Gandhi TK, Weingart SN, Seger AC, et al. Outpatient prescribing errors and the impact of computerized prescribing. J Gen Intern Med. 2005; 20(9): 837-841



Weingart SN, Simchowitz B, Padolsky H, et al. An Empirical Model to Estimate the Potential Impact of Medication Safety Alerts on Patient Safety, Health Care Utilization, and Cost in Ambulatory Care. Arch Intern Med. 2009;169(16):1465-1473



Isaac T, Weissman JS, Davis RB, et al. Overrides of Medication Alerts in Ambulatory Care. Archives of Internal Medicine 2009; 169(3): 305-311



Gurwitz JH, Field TS, Harrold LR, et al. Incidence and preventability of adverse drug

events among older persons in the ambulatory setting. JAMA 2003;289:1107-16



Bohnert ASB, Valenstein M,  Bair MJ, et al. Association Between Opioid Prescribing Patterns and Opioid Overdose-Related Deaths

JAMA. 2011; 305(13): 1315-1321



Cohen M. Doctors risk patient safety by prescribing fentanyl painkiller for short-term pain. November 8, 2010



National Patient Safety Agency (UK). Patient Safety Alert: The adult patient’s passport to safer use of insulin. March 30, 2011



Insulin “passport” (foldable list)



Patient information booklet for insulin passport



Massachusetts Coalition for the Prevention of Medical Errors. Patient Med List.



AHRQ411 “How to Create a Pill Card”.



Wolf MS; Curtis LM, Waite K, et al. Helping Patients Simplify and Safely Use Complex Prescription Regimens. Arch Intern Med. 2011; 171(4): 300-305



Schillinger D, Machtinger E, Wang F, Rodriguez M, Bindman A. Preventing medication errors in ambulatory care: the importance of establishing regimen concordance. In: Henriksen K, Battles J, Lewin DI, Marks E, eds. AHRQ Peer-Reviewed Publication: Advances in Patient Safety: From Research to Implementation, Vol. 2. Rockville, MD; 2005.









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