The concept of the prescribing cascade was introduced by Rochon and Gurwitz^1,2 in the 1990s and has been a key concept in the field of geriatric pharmacotherapy since that time. The prescribing cascade begins when an adverse drug reaction is misinterpreted as a new medical condition, and another drug is prescribed to treat this presumed new condition. This second drug can sometimes produce a new adverse drug effect, which then triggers additional drug therapy.

One example of the prescribing cascade is the misdiagnosis of extrapyramidal side effects from metoclopramide, resulting in the initiation of therapy with levodopa/carbidopa or another medication for Parkinson’s disease. In a 1995 study with the New Jersey Medicaid population, Avorn and colleagues found that older adults who were receiving metoclopramide were three times more likely to have drug therapy initiated for Parkinson’s disease.³

Despite the time that has passed since this problem has been identified, a study reported earlier this year by Esper and Factor reveals that the lack of recognition of drug-induced Parkinsonism in the elderly continues to be a problem.⁴ The authors conducted a retrospective review of 354 Parkinsonian patients evaluated by neurologists in a movement disorders clinic. They found that 24 patients (6.8%) had drug-induced Parkinsonism. Of these cases, metoclopramide was responsible for 29% and atypical antipsychotics were responsible for 46%.

What was particularly alarming was that only one of the 24 patients with drug-induced Parkinsonism had been accurately diagnosed. If neurologists in a movement disorders clinic are failing to find these problems, it is unlikely that primary care physicians and psychiatrists are doing better.

In a more recent example of the prescribing cascade, Gill and colleagues conducted a study of older adults with dementia in Canada.⁵ Those who received cholinesterase inhibitors—donepezil, rivastigmine, and galantamine—were over 50% more likely to receive an anticholinergic drug to manage urinary incontinence. Clearly, giving an anticholinergic medicine while also giving a cholinergic medicine is likely to minimize the benefits of both medications.

In a study reported in the October 2008 issue of Drugs & Aging, Johnell and Fastbom confirmed the increased likelihood of the use of anticholinergic medications in older adults taking cholinesterase inhibitors.⁶ In the Swedish population involved in this study, they found that male sex and use of many drugs were independently associated with concurrent use of anticholinergic drugs and cholinesterase inhibitors.

The concomitant use of bladder anticholinergics and cholinesterase inhibitors has been found to accelerate functional decline compared to residents taking the cholinesterase inhibitor alone. Sink and colleagues studied 3,536 nursing home residents in Indiana taking a cholinesterase inhibitor.⁷ They found that 10.6% of these residents were also taking oxybutynin or tolterodine. Those taking the combination of medications had a 50% greater rate of quarterly decline in activities of daily living compared to those taking the cholinesterase inhibitor alone.

These are just two examples of the prescribing cascade that are still relatively common. Consultant and senior care pharmacists can make an important contribution to patient care by identifying patients who may be victims of these prescribing cascades and alerting prescribers so that appropriate changes can be made.

The Centers for Disease Control and Prevention (CDC) has launched a campaign to promote appropriate use of antibiotics. The campaign, titled "Get Smart: Know When Antibiotics Works," targets use of antibiotics in the community. The campaign's Web site address is http://www.cdc.gov/drugresistance/community.

The CDC previously launched another campaign to prevent development of antibiotic resistance in health care settings, including long-term care. The Web site address for that campaign is http://www.cdc.gov/drugresistance/healthcare/default.htm.

The Centers for Disease Control and Prevention (CDC) has updated its seasonal influenza Web page with questions and answers about the current flu season. The supply of influenza vaccine this year is expected to be adequate.

CDC's primary Web page on influenza is at http://www.cdc.gov/flu.

Another Web site that is useful for tracking influenza throughout the flu season is FluStar . This Web site provides current information on influenza status by zip code, and also has an e-mail alert service.

The Quality Standards Subcommittee of the American Academy of Neurology and the European Federation of Neurological Societies has released a report recommending carbamazepine (Level A evidence) or oxcarbamazepine (Level B) for pharmacotherapy of trigeminal neuralgia. Lamotrigine and baclofen (Level C) may also be considered useful.

View the abstract and full report at http://www.neurology.org/cgi/content/full/71/15/1183.

Neurology 2008;71:1183-1190.

1. Rochon PA, Gurwitz JH. Drug therapy. Lancet 1995;346:32-6.
2. Rochon PA, Gurwitz JH. Optimising drug treatment for elderly people: the prescribing cascade. BMJ 1997;315:1096-9.
3. Avorn J, Gurwitz JH, Bohn RL, et al. Increased incidence of levodopa therapy following metoclopramide use. JAMA 1995;274(22):1780-2.
4. Esper CD, Factor SA. Failure of recognition of drug-induced parkinsonism in the elderly. Mov Disord 2008;23(3):401-4.
5. Gill SS, Mamdani M, Naglie G, et al. A prescribing cascade involving cholinesterase inhibitors and anticholinergic drugs. Arch Intern Med 2005;165:808-13.
6. Johnell K, Fastbom J. Concurrent use of anticholinergic drugs and cholinesterase inhibitors: Register-based study of over 700,000 elderly patients. Drugs & Aging 2008;25(10):871-7.
7. Sink KM, Thomas J, Xu H, et al. Dual use of bladder anticholinergics and cholinesterase inhibitors: Long-term functional and cognitive outcomes. J Am Geriatr Soc 2008;56:847-53.