Dr. Howland is Associate Professor of Psychiatry, University of Pittsburgh School of Medicine, Western Psychiatric Institute and Clinic, 3811 O’Hara Street, Pittsburgh, Pennsylvania.
The author discloses that he has no significant financial interests in any product or class of products discussed directly or indirectly in this activity, including research support.
Address correspondence to Robert H. Howland, MD, Associate Professor of Psychiatry, University of Pittsburgh School of Medicine, Western Psychiatric Institute and Clinic, 3811 O’Hara Street, Pittsburgh, PA 15213; e-mail: HowlandRH@upmc.edu.
Age-related changes in pharmacokinetic and pharmacodynamic drug processes, discussed in last month’s Psychopharmacology article, have potentially important implications for psychotropic medication use in older adults. However, with the exception of a few drug classes, such as medications for dementia, elderly patients are underrepresented in clinical studies of most psychotropic drugs. This occurs because clinical trials often exclude patients with comorbid medical and psychiatric disorders, as well as patients taking multiple medications (Banerjee & Dickinson, 1997). Hence, much of what we know about the use of medications is based on studies that cannot be readily generalized to elderly patients. This is surprising and very disconcerting, given that elderly patients take many more medications than younger patients. In this article, I will discuss how the tolerability and safety of drugs differ in older individuals and how medications should be prescribed for elderly patients.
Adverse Medication Effects in Older Adults
Compared with younger patients, the use of various psychotropic drugs is typically associated with expected, but exaggerated adverse effects in elderly patients. In addition, some drugs are associated with adverse effects that are unique to older adults.
Hyponatremia is a rare and potentially serious complication associated with the use of serotonergic drugs in elderly patients, including the selective serotonin reuptake inhibitor (SSRI) and serotonin-norepinephrine reuptake inhibitor (SNRI) antidepressant drugs, especially when they are used together with diuretic and other drugs that might contribute to hyponatremia (Egger, Muehlbacher, Nickel, Geretsegger, & Stuppaeck, 2006). Possible symptoms are irritability, confusion, and lethargy, and seizures are a major risk.
The use of SSRI and SNRI drugs has been associated with easy bruising and prolonged bleeding times (Yuan, Tsoi, & Hunt, 2006). Rarely, serious upper gastrointestinal bleeding has been described, primarily among elderly patients taking nonsteroidal anti-inflammatory drugs (NSAIDs). Elderly patients should be assessed for bruising or bleeding during clinical visits, particularly if they are taking NSAIDs or any prescription or nonprescription drug that might affect coagulation (e.g., heparin, fish oil supplements, vitamin E).
Older adults are especially sensitive to the effects of anticholinergic and antihistamine drugs, including blurred vision, dry mouth, urinary retention, constipation, cognitive impairment, confusion, and delirium (Roberts & Tumer, 1998). In addition to medications that are primarily classified as anticholinergic or antihistamine, many drugs have inherent anticholinergic or antihistamine effects. Examples include some antidepressant drugs (especially tricyclic antidepressant agents and mirtazapine [Remeron®]) and some antipsychotic drugs (i.e., low-potency typical antipsychotic drugs, several of the atypical antipsychotic drugs), as well as many nonprescription medications marketed for insomnia, diarrhea, allergies, headache, and pain.
Older patients are more sensitive to drugs’ effects on cardiac function, including changes in heart rate, blood pressure, and heart rhythm. The psychotropic drugs most likely to have an effect on cardiac function are tricyclic antidepressant, monoamine oxidase inhibitor antidepressant, and most of the typical and atypical antipsychotic drugs. These effects are magnified in patients taking other nonpsychotropic drugs that affect cardiac function.
Elderly patients are more susceptible to the extrapyramidal (parkinsonian) effects of anti-psychotic medications (Martí Massó & Poza, 1996). Although this is more pronounced with the use of typical antipsychotic drugs, it is also a concern with atypical drugs. There is a small elevated risk of adverse cerebrovascular events (i.e., stroke) and death associated with the use of all antipsychotic drugs in elderly patients with dementia-related psychosis (Howland, 2008).
Lithium and mood-stabilizer anticonvulsant drugs are associated with greater adverse neurological effects in elderly patients, such as tremors and ataxia, as well as sedation, cognitive impairment, and confusion (Mulsant & Pollock, 2004). Similarly, benzodiazepine and other sedative-hypnotic drugs can cause more sedation, cognitive impairment, confusion, and ataxia.
Falls are the single most important serious complication associated with all types of prescription and nonprescription drug use in older adults. All psychotropic drugs increase the risk of falls. No particular drug or class of drugs should be considered risk free. Psychotropic drugs contribute to or cause falls by various direct and indirect mechanisms, including sedation, confusion, vision changes, blood pressure changes, cardiac rhythm changes, balance problems, and neuromuscular in-coordination. The risk of falls is increased when multiple medications are used and among patients who have comorbid medical conditions.
Clinical Use of Medications in Older Adults
As a general principle, elderly patients should be started on low dosages of medication. Depending on the patient’s age, general health, and use of other medications, the starting dosage would typically be one third to one half the amount that might be started for a younger patient. If using smaller initial dosages is not practical based on the product (i.e., pills that cannot be cut, capsule formulations), dosing could commence using the smallest available unit dosage given every other day or every third day. The schedule for upward dosage titration should also be slower for elderly patients. Although the targeted therapeutic dosage of a medication is generally expected to be lower for elderly patients, some will still require higher dosages within the recommended range.
Patients should not be under-treated using subtherapeutic dosages of medication simply because they are older and are “expected” to require lower dosages. To avoid this problem, elderly patients should be monitored carefully for therapeutic efficacy as well as adverse effects during the titration phase of medication. However, because of the potential risk of drug accumulation over time, elderly patients also need to be monitored closely during longer-term therapy for the delayed development of adverse effects, especially with the use of long-acting injectable medications.
The selection of medication should be “matched” to the patient on the basis of his or her particular clinical characteristics. Such clinical characteristics include mental health symptoms, all known medical comorbidities, and current medication regimen. All prescription and nonprescription medications, other drug products (including vitamins, supplements, and herbal products), alcohol, nicotine, and illicit drugs should be recorded. The choice of medication should be based on knowledge of the known side effect profile of available drugs, as well as any potential adverse effects unique to older adults. Although not always clinically possible, selecting a medication with the least expected “unsafe” profile is preferred when multiple medications are available. Medications with short half-lives and no active metabolites are preferred.
The patient’s medication regimen should be simplified whenever possible. Doing so requires attention to the number and types of all psychotropic and nonpsychotropic medications taken, the timing of medication dosages, eliminating unnecessary medications, and avoiding potential drug-drug interactions. This involves active cooperation among all of the patient’s health care providers, along with counseling the patient and family or other caregivers. Medications should be reviewed at all clinical visits with the patient and family or other caregivers. Information about medications and medication changes should be given in writing, using language they can read and understand, and should be reinforced verbally.
Laboratory testing can be useful in some ways for monitoring pharmacotherapy in elderly patients, but this should not be considered an appropriate substitute for careful clinical assessment and sound clinical judgment. The kinds of blood tests usually ordered for liver function or liver enzymes are not useful for measuring the metabolism of drugs or for predicting medication dosages, although they can sometimes demonstrate the damaging effects of certain medications on the liver. By contrast, renal function tests do provide useful information about the patient’s capacity to excrete drugs through the kidneys. This is most important clinically for the use of lithium, but also for other psychotropic drugs whose clearance is highly dependent on kidney functioning.
Measuring serum drug concentrations is possible for all medications. However, this information is difficult to interpret or use clinically, because the clinical or scientific basis for the drug concentration reference range that is usually printed on the laboratory report is typically not well established, for determining either a “therapeutic” or a “toxic” level. Exceptions include lithium, some anticonvulsant drugs, and some tricyclic antidepressant drugs. Measuring serum electrolytes is important for monitoring patients taking drugs that can cause hyponatremia. The electrocardiogram is used for monitoring the cardiac effects of certain medications, but assessing orthostatic (i.e., from sitting to standing) heart rate and blood pressure changes at each visit provides more practical information about cardiovascular function, which is especially helpful in assessing the risk of falls.
Nurses often have the most direct and frequent contact with patients, families, caregivers, and other health care providers. In their role of providing, monitoring, and coordinating treatment, nurses should be very knowledgeable about the appropriate use and clinical monitoring of medication in elderly patients (Banning, 2005; Miller, 2003).
- Banerjee, S. & Dickinson, E. (1997). Evidence-based health care in old age psychiatry. International Journal of Psychiatry in Medicine, 27, 283–292.
- Banning, M. (2005). Medication management: Older people and nursing. Nursing Older People, 17(7), 20–23.
- Egger, C., Muehlbacher, M., Nickel, M., Geretsegger, C. & Stuppaeck, C. (2006). A review of hyponatremia associated with SSRIs, reboxetine, and venlafaxine. International Journal of Psychiatry in Clinical Practice, 10, 17–26. doi:10.1080/13651500500410216 [CrossRef]
- Howland, R.H. (2008). Risks and benefits of antipsychotic drugs in elderly patients with dementia. Journal of Psychosocial Nursing and Mental Health Services, 46(11), 19–23. doi:10.3928/02793695-20081101-05 [CrossRef]
- Martí Massó, J.F. & Poza, J.J. (1996). Drug-induced or aggravated parkinsonism: Clinical signs and the changing pattern of implicated drugs. Neurología, 11, 10–15.
- Miller, C.A. (2003). Safe medication practices: Nursing assessment of medications in older adults. Geriatric Nursing, 24, 314–317. doi:10.1016/S0197-4572(03)00256-8 [CrossRef]
- Mulsant, B.H. & Pollock, B.G. (2004). Psychopharmacology. In Blazer, D.G., Steffens, D.C. & Busse, E.W. (Eds.), Textbook of geriatric psychiatry (3rd ed., pp. 387–411). Washington, DC: American Psychiatric Publishing.
- Roberts, J. & Tumer, N. (1998). Pharmacodynamic basis for altered drug action in the elderly. Clinics in Geriatric Medicine, 4, 127–149.
- Yuan, Y., Tsoi, K. & Hunt, R.H. (2006). Selective serotonin reuptake inhibitors and risk of upper GI bleeding: Confusion or confounding?American Journal of Medicine, 119, 719–727. doi:10.1016/j.amjmed.2005.11.006 [CrossRef]