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Psychiatric symptoms of dementia: Treatable, but no silver bullet

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References

Choosing an antidepressant

Only a few randomized controlled trials of antidepressants for depression with dementia have been completed, each with a small number of patients.

Table 3 is a guide to choosing an antidepressant based on published evidence but organized according to our experience. The algorithm assumes that the physician has considered whether drugs and coexisting medical conditions might be contributing to the depressive symptoms. The algorithm also assumes that the physician has ruled out bipolar disorder as a cause of behavioral symptoms mimicking hypomania such as reduced sleep, irritability, excessive spending, and pressured speech.

Mirtazapine (Remeron) is what we recommend to improve sleep and appetite and restore lost weight. 21 It can be used in patients with Parkinson disease or parkinsonian symptoms who experience increased tremors or bradykinesia with selective serotonin reuptake inhibitors (SSRIs). On the other hand, it may not be the best option for those with diabetes mellitus, metabolic syndrome, hyperlipidemia, or obesity. It may rarely also cause a reversible agranulocytosis.

Venlafaxine (Effexor) and duloxetine (Cymbalta) are serotonin-norepinephrine reuptake inhibitors (SNRIs) and may help in concomitant pain syndromes. 22 Either drug can cause anorexia at any dose and can elevate blood pressure at higher doses. Venlafaxine may also cause insomnia in some patients.

Bupropion (Wellbutrin) can be difficult to titrate to an effective dose in an older person with unsuspected renal insufficiency, and it may interact at the P450 complex. 23 The risk of seizures is greater at higher bupropion serum levels. There is also a high incidence of weight loss. Frail elderly patients, those with hypertension, and those vulnerable to hallucinations will likely do better with another drug.

Nefazodone is a third- or fourth-line antidepressive choice because of the risk of hepatic failure. However, it can help reduce disabling anxiety associated with depression. The FDA requires periodic liver function testing if this drug is used.

Trazodone in low doses (≤ 100 mg) each evening may help with sleep, but it cannot be titrated to antidepressive doses in older adults because of orthostatic effects.

Nortriptyline is recommended by some geriatricians for depression or pathologic crying in patients with mixed vascular dementia. However, it often causes cardiac conduction delays with reflex sympathetic tachycardia and anticholinergic side effects.

Monoamine oxidase inhibitors interact with many foods and drugs, limiting their use in older adults.

Methylphenidate (Ritalin) at low doses is used off-label for depression in palliative care, with noted rapid improvements in mood and appetite. 24 Monitoring for increases in blood pressure, heart rate, and respiratory rate is essential if this stimulant is chosen. Patients who respond may make a transition to other traditional drugs after 2 to 4 weeks.

Caveats with SSRIs

  • Despite the safety profile of SSRIs in older adults, care must be taken when prescribing them to frail elderly patients, given recent data associating SSRIs with falls and fragility fractures 25,26 and urinary incontinence. 27
  • SSRIs may decrease appetite during initial treatment.
  • Sertraline (Zoloft) may have to be started at a very low dose to decrease possible adverse gastrointestinal symptoms, such as diarrhea.
  • Paroxetine (Paxil) has multiple interactions at the cytochrome P450 complex and has the most anticholinergic properties of the SSRIs, rendering it more likely to cause adverse drug reactions, constipation, and delirium.
  • Daily fluoxetine (Prozac) may not be appropriate in older adults because of its long half-life and the risk of insomnia and agitation. 28
  • Tremors can emerge with all the SSRIs; akathisia, dystonia, and parkinsonism are also possible. 29
  • Hyponatremia, bruising, and increased bleeding time can occur with any SSRI.
  • Abrupt cessation of any SSRI except fluoxetine (due to its long half-life) or of SNRIs may cause a very unpleasant flu-like withdrawal syndrome.
  • Apathy can be a reversible, dose-dependent adverse effect of SSRIs in young persons 30; there are no data on the dose at which this adverse effect might emerge in demented elderly patients.

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