Why Tapering is Necessary When Switching Between SSRIs in Elderly Patients
Even when switching between two SSRIs like sertraline and citalopram, tapering is necessary to minimize the risk of SSRI discontinuation syndrome, which can cause dizziness, paresthesias, anxiety, irritability, and other distressing symptoms—particularly important in elderly patients with Alzheimer's disease who may be unable to articulate these symptoms clearly. 1, 2, 3
Understanding SSRI Discontinuation Syndrome
Despite both medications being SSRIs, abrupt discontinuation of either sertraline or citalopram can trigger withdrawal symptoms because:
The FDA labels for both sertraline and citalopram explicitly warn that "abrupt discontinuation can be associated with certain symptoms" and recommend tapering "as rapidly as is feasible" when discontinuing treatment 2, 3
Discontinuation symptoms include dizziness, fatigue, nausea, headaches, insomnia, anxiety, and sensory disturbances—symptoms that can be particularly problematic in elderly patients with dementia who cannot reliably communicate their discomfort 4
Citalopram has a relatively lower risk of discontinuation syndrome compared to paroxetine and fluvoxamine, but the risk still exists and warrants gradual tapering 4
Why Cross-Tapering Doesn't Eliminate the Risk
The common misconception is that starting the new SSRI immediately will prevent withdrawal symptoms. However:
Each SSRI has unique pharmacokinetic properties, receptor binding profiles, and half-lives that don't provide complete cross-protection during the transition period 1
Sertraline and citalopram, while both SSRIs, have different potencies at the serotonin transporter and different metabolic pathways, meaning one does not fully substitute for the other during the initial switch 5, 6
Special Considerations in Elderly Alzheimer's Patients
This population requires particular caution:
Elderly patients are at higher risk for adverse drug reactions, and cognitive impairment makes it difficult for them to report discontinuation symptoms, potentially leading to misinterpretation as worsening dementia or behavioral disturbance 1
The FDA specifically notes that families and caregivers should monitor for "agitation, irritability, unusual changes in behavior" during medication changes, as these may represent discontinuation symptoms rather than disease progression 2, 3
In the context of treating hypersexuality in Alzheimer's disease with SSRIs, abrupt medication changes could destabilize both the behavioral symptoms and the patient's overall neuropsychiatric status 7
Recommended Tapering Approach
Gradually taper the current SSRI over 10-14 days while simultaneously starting the new SSRI at a low dose, then titrate the new medication upward as the old one is discontinued 1
For elderly patients, start sertraline at 25 mg daily (half the standard adult starting dose) when switching from citalopram 1
Monitor closely during the first 2-4 weeks for emergence of discontinuation symptoms, worsening behavioral symptoms, or new adverse effects 1, 2, 3
Common Pitfall to Avoid
Never perform an abrupt "cold turkey" switch between SSRIs in elderly patients, even though guidelines support direct switching in younger, healthier adults—the elderly with dementia require more conservative transitions due to their vulnerability to discontinuation symptoms and inability to reliably report them 1, 4