Lower risk of adverse drug reactions in elderly
August 1, 2002 5 minutes read
When an elderly man came to the emergency department (ED) complaining of general malaise, a potassium level of 6.2 was discovered. Although the man had run out of his prescribed diuretic, he had continued taking his potassium supplement.
"He was continuing to take the supplement because the doctor told me to take this medication,’ even though he had been unable to refill the [furosemide]," says Fred A. Neis, RN, MS, CEN, NREMT-P, interim clinical coordinator for the ED at Oregon Health & Science University/Doernbecher Children’s Hospital in Portland. "He did not understand the relationship between the two medications." Discontinuing the diuretic and continuing to take the potassium supplement can lead to hyperkalemia, which is a potentially life-threatening situation, says Neis.
Neis gives another example of an elderly patient taking warfarin who presented to the ED with a hypercoagulable state. "We also see the patient who presents with dehydration or impaired renal function and thus may have digoxin toxicity," he says. Recently, an elderly patient was found to have angioedema caused by angiotensin I-converting enzyme (ACE) inhibitors, reports Neis. "This was originally diagnosed as a drug reaction from the new antibiotic the patient had been prescribed," he says.
When the patient had complained of a swollen tongue, his primary care provider discontinued the antibiotic, assuming it was the cause. "However, the patient then presented to the ED a week later with the same complaint," says Neis. "The ED physician reviewed the medication list and became suspicious of the ACE inhibitor." When this medication was discontinued, the angioedema resolved within a couple of days, he adds.
Neis acknowledges that it can be difficult to pinpoint adverse drug reactions in the ED because the patient may complain of a variety of symptoms, such as abdominal pain, respiratory distress, headache, and dizziness. While your ED evaluation should address the possibility of an adverse drug reaction, you also must consider potentially life-threatening diagnoses such as myocardial infarction, congestive heart failure, and bowel obstruction, he cautions.
Here are some ways to prevent adverse drug reactions in elderly patients:
• Realize that patients probably are taking multiple medications. Neis points to a recent study which found that elderly ED patients averaged 5.9 prescription medications.1 He recommends advising elderly patients to have a single pharmacy tracking and dispensing all of the patient’s prescriptions. "Many pharmacies are equipped to uncover potential medication reactions," he says.
Take time to educate patients
• Explain how new medications should be incorporated with existing medications. In the above study, only 42% of elderly patients were able to identify all of the medications they were currently taking.
Karen Hayes, PhD, ARNP, professor at the School of Nursing at Wichita (KS) State University, urges you to discuss with patients how to incorporate new medications into their current regime. "This is often a source of confusion," she says. She advises you to remind patients to continue their routine medications if appropriate.
• Instruct patients to follow up with their primary care provider. This is particularly important if any dosages of current medicines were changed in the ED or any new medications added, says Neis. With the increased use of technology and computerized medical records for entire health systems, physicians, pharmacists, and nurses are better connected to the patient’s full medical record, says Neis, which should help prevent adverse drug reactions.
• Consider the elderly patient’s nutritional status. Neis says this is an important education piece for the patient taking drugs that are metabolized and excreted through the renal or hepatic systems, or medications that are sometimes not tolerated well in the gastrointestinal system without food.
• Educate patients to prevent future problems. Hayes points to a study that assessed the prevalence of elderly ED patients with drug-related problems — and whether they could have been prevented. "The investigators determined that 28% of the elders presented to the ED with a drug-related problem," she says. "Most were preventable."2
Hayes says you can prevent problems by carefully explaining medication instructions, monitoring side effects, and educating patients. She acknowledges that ED nurses face a challenge in educating elderly patients about their medications, especially when the patient already has a very complex medication regimen to follow. Hayes recommends giving patients medication instructions in written form, using large print and vocabulary for a fifth-grade (or below) reading level and reinforcing these instructions with verbal teaching.
• Always ask patients about new or recently added medications. When an elderly woman recently presented to the ED with complaints of dizziness, headache, tremor, and confusion, she was underwent a computerized tomography of the head, electroencephalogram, and extensive laboratory testing. "All of the work-up was negative," says Hayes. It was later discovered that the patient recently had started taking an antidepressant. "Although she told the nurse about the antidepressant, she did not disclose it was a recent addition to her medications," says Hayes. "The symptoms stopped after the antidepressant was stopped."
Another example of problems with new medications is the frail, elderly female who presented with abdominal pain, Hayes says, explaining that 2,300 cc of urine was obtained upon catheterization. "The patient had recently begun on [oxybutynin] for urinary incontinence," says Hayes.
References
1. Chung MK, Bartfield JM. Knowledge of prescription medications among elderly emergency department patients. Ann Emerg Med 2002; 39:605-608.
2. Tafreshi MJ, Melby MJ, Kaback KR, et al. Medication-related visits to the emergency department: A prospective study. Ann Pharmacother 1999; 33:1,252-1,257.
Sources
For more information about elderly patients and adverse drug reactions, contact:
• Karen Hayes, PhD, ARNP, School of Nursing, Wichita State University, 1845 Fairmount, Wichita, KS 67260. Telephone: (316) 978-5721. E-mail: [email protected].
• Fred A. Neis, RN, MS, CEN, NREMT-P, Interim Clinical Coordinator, Emergency Department, Oregon Health & Science University, Emergency Department, 3181 S.W. Sam Jackson Park Road, Mail Code UHS 40, Portland, OR 97201. Telephone: (503) 494-6051. Fax: (503) 494-0299. E-mail: [email protected].
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