Optimal management of dementia: a practical approach

Contributed by:

Lesley Charles, MBChB, CCFP(COE)
(Click for bio)

Case

Mr. Philips is 82 years old. He is presenting with a two-year history of gradual decline in cognition, which is affecting his daily function including missing bills and forgetting to take his medications. His past medical history includes hypertension, dyslipidemia, STEMI, LBBB, anxiety, depression, insomnia and benign prostatic hyperplasia. His current medications include ramipril 5 mg daily, atorvastatin 40 mg daily, ECASA 81 mg daily, citalopram 40 mg daily, quetiapine 25 mg qhs and tamsulosin 0.4 mg daily.

Issue

In primary care settings, more than half of dementia cases are missed and when recognized they are often undertreated. Patients living with dementia are projected to place an increasing burden on the health care system. Optimal management of dementia may help alleviate some of this. This article provides a practical approach to prescribing in dementia.

Background

The risk of dementia rises with age. The prevalence of dementia is 8% in those over 65 living in the community or facility living.¹ Family physicians are often the first point of contact for patients and their families thus it is important that they be skilled in diagnosing and managing dementia.²

Diagnosis should center on the DSM-5 criteria for significant cognitive decline interfering with independence in daily activities while ruling out the possibility of delirium, depression and drug side effects.³ Canadian research has shown the majority of dementia diagnoses are happening at the specialist level.⁴ There are many barriers to the diagnosis of dementia in primary care. Knowledge base around dementia, misdiagnosis, perception of futility of diagnosis and treatment are common barriers,^5-7 as is the length of time the assessment may take. There is potential for primary care to decrease the burden of dementia.⁸

Evidence

In accordance with DSM-5, delirium is ruled out in Mr. Philips’ case as this has been a gradual progression.³ His mood is stable on citalopram, but his dose is higher than what is recommended for elderly patients. Health Canada recommends a maximum dose of 20 mg for citalopram in elderly patients because of the potential to prolong the QTc9. Quetiapine should be reviewed in terms of appropriate use of antipsychotics. Antipsychotic side-effects include agitation, confusion, falls, insomnia and sedation along with increased risk of infection, strokes and cardiac events.¹⁰ In Mr. Phillip’s case he is taking it for insomnia.

The patient is diagnosed with a dementia, given his symptoms and functional decline, and consideration is given to pharmacological treatment. An individualized approach is recommended taking into account patient preferences, benefits and risks. The most commonly prescribed medications in dementia are cholinesterase inhibitors (e.g., galantamine, donepezil and rivastigmine) and NMDA antagonists (e.g., memantine).^11-13 Publicly funded drug benefit programs in all Canadian provinces now provide coverage for cholinesterase inhibitors when used to treat mild-to-moderate Alzheimer disease.

Physicians prescribing cholinesterase inhibitors should be aware of the starting doses, titration regimens, contraindications, precautions and adverse effects. Conduction abnormalities other than a right bundle-branch block are considered contraindications.¹⁴ Other contraindications are known hypersensitivity to the drug or unexplained syncope. In addition, galantamine has severe hepatic and renal impairment as contraindications and rivastigmine is contraindicated in severe hepatic impairment. Both drugs should be used with caution in patients with risk of ulcers and gastrointestinal bleeding, history of seizures, asthma, COPD or low body weight. Memantine is contraindicated if there is a known hypersensitivity to drug or severe renal impairment.¹⁴ The most common side effects of cholinesterase inhibitors are gastrointestinal, e.g., anorexia, nausea, vomiting and diarrhea. Such effects are most likely to occur at the start of therapy or when the dose is increased. Weight loss and dizziness are other commonly seen side effects.¹⁴ If side effects occur the medication should be dose reduced or stopped altogether. Consideration can be given to another cholinesterase inhibitor.

Memantine is recommended as monotherapy or as an adjunct to cholinesterase inhibitor in moderate to severe dementia.¹⁵ Combination therapy is well tolerated, with a safety profile similar to that seen with cholinesterase inhibitor therapy alone. There are cost restrictions for some patients as it is not covered by Alberta Blue Cross.

If pharmacotherapy is initiated, patients should be followed carefully for the development of adverse effects and re-evaluated to determine their response to therapy after a reasonable trial, i.e., three to six months.¹⁴ If one cholinesterase inhibitor is not well tolerated or deemed ineffective, patients can be switched to another one or to memantine.^{16, 17}

Back to the Case

It was recommended to reduce citalopram to 30 mg daily for two weeks then 20 mg daily while watching for increasing depression. Similarly, it was recommended to decrease quetiapine to 12.5 mg for two weeks then discontinue. Mr. Phillips was not prescribed a cholinesterase inhibitor because of his LBBB. A trial of memantine was commenced with follow up in three months.

Recommendation

Dementia is prevalent and undertreated in primary care but there is potential for primary care providers to decrease its burden upon the health system. Patients should be assessed, and consideration given to treatment in primary care, taking into account patient preferences, benefits and risks. A dementia strategy can improve the diagnosis and treatment of dementia in primary care.¹⁸

References

1. Canadian study of health and aging: study methods and prevalence of dementia. CMAJ. 1994 Mar 15; 150(6):899-913.
2. Hum S, Cohen C, Persaud M, Lee J, Drummond N, Dalziel W, Pimlott N. Role expectations in dementia care among family physicians and specialists. Can Geriatr J. 2014 Sep; 17(3):95-102.
3. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. Fifth Edition. Arlington, VA: American Psychiatric Association; 2013.
4. Neil Drummond, PhD, Richard Birtwhistle, MD, MSc, Tyler Williamson, PhD, Shahriar Khan, MSc, MA, Stephanie Garies, MPH, and Frank Molnar, MSc, MDCM. Prevalence and management of dementia in primary care practices with electronic medical records: a report from the Canadian Primary Care Sentinel Surveillance Network. CMAJ Open. 2016 Apr-Jun; 4(2): E177–E184.
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8. Toronto: Alzheimer Society of Canada. Rising tide: the impact of dementia on Canadian society. 2010.
9. Health Canada Endorsed Important Safety Information on CELEXA® (citalopram hydrobromide). https://www.lundbeck.com/upload/ca/en/files/pdf/productcommunication/Celexa%20HPC_ENG_%20e-signature_20Jan2012.pdf
10. Appropriate Use of Antipsychotic Medications. https://www.albertahealthservices.ca/scns/auatoolkit.aspx
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14. Hogan D, Bailey P, Black S, et al. Diagnosis and treatment of dementia: 5. Nonpharmacologic and pharmacologic therapy for mild to moderate dementia. CMAJ. 2008 Nov 4;179(10):1019-26. doi: 10.1503/cmaj.081103
15. Areosa SA, Sherriff F, McShane R. Review Memantine for dementia. Cochrane Database Syst Rev.
16. Hogan DB, Bailey P, Carswell A, Clarke B, Cohen C, Forbes D, Man-Son-Hing M, Lanctôt K, Morgan D, Thorpe L. Management of mild to moderate Alzheimer's disease and dementia. Alzheimers Dement. 2007 Oct; 3(4):355-84.
17. Waldemar G, Hyvärinen M, Josiassen MK, Kørner A, Lehto H, Wetterberg P. Tolerability of switching from donepezil to memantine treatment in patients with moderate to severe Alzheimer's disease. Int J Geriatr Psychiatry. 2008 Sep; 23(9):979-81.
18. Mukadam N, Livingston G, Rantell K, Rickman S. Diagnostic rates and treatment of dementia before and after launch of a national dementia policy: an observational study using English national databases. BMJ Open. 2014 Jan 9;4(1):e004119. doi: 10.1136/bmjopen-2013-004119.