Can a 78-year-old female on divalproex sodium and lacosamide be started on escitalopram (Lexapro) for inappropriate sexual behaviors?

Can Escitalopram (Lexapro) Be Started in This Patient?

Yes, escitalopram can be initiated in this 78-year-old female on divalproex sodium and lacosamide for inappropriate sexual behaviors, but this requires careful consideration of drug interactions, geriatric-specific risks, and the paradoxical nature of using an SSRI for sexual disinhibition.

Critical Safety Considerations

Drug-Drug Interactions

The 2019 AGS Beers Criteria 1 specifically warns about concurrent use of three or more CNS-active agents (antidepressants, antiepileptics, and others), which increases fall risk in older adults. Your patient is already on two antiepileptic drugs (divalproex sodium and lacosamide), and adding escitalopram would create a three-drug CNS regimen—this combination requires heightened vigilance for:

• Increased sedation
• Cognitive impairment
• Fall risk
• Potential serotonin syndrome (though less likely with antiepileptics)

Geriatric-Specific Risks with SSRIs

The FDA label for Lexapro 2 and AGS Beers Criteria 1 highlight several concerns in older adults:

• Hyponatremia/SIADH risk (particularly relevant as patient is already on divalproex)
• Increased bleeding risk if on anticoagulants or NSAIDs
• Cognitive/motor impairment compounding existing issues
• Falls and fractures from combined CNS depression

The Paradox: SSRIs for Sexual Disinhibition

Here's the clinical reasoning: While SSRIs like escitalopram commonly cause sexual dysfunction 2, 3, 4, this side effect becomes therapeutic in managing inappropriate sexual behaviors. The mechanism involves:

• Serotonergic suppression of sexual drive and arousal
• Delayed orgasm/anorgasmia effects
• Reduced libido

Evidence for this approach: A 2008 review 5 examining inappropriate sexual behaviors in cognitively impaired elderly found that SSRIs are reasonable first-line agents (after TCAs) for managing sexual disinhibition, particularly when behaviors don't involve dangerous physical contact. The serotoninergic effects that typically constitute "side effects" become the desired therapeutic outcome.

Practical Implementation Algorithm

Step 1: Assess Appropriateness

• Use escitalopram IF: Behaviors are primarily verbal or non-contact physical gestures
• Consider alternatives IF: Behaviors involve dangerous physical contact (antiandrogens or LHRH agonists may be needed) 5
• Rule out: Delirium, UTI, pain, or medication-induced disinhibition from current drugs

Step 2: Dosing Strategy

• Start low: 5 mg daily (lower than standard 10 mg starting dose given age and polypharmacy)
• Titrate slowly: Increase by 5 mg every 2-4 weeks if needed
• Maximum dose: 10 mg daily in elderly 2 (avoid higher doses given hepatic metabolism concerns and drug interactions)

Step 3: Monitoring Protocol

• Week 1-2: Daily assessment for sedation, confusion, falls
• Week 2-4: Check sodium levels (hyponatremia risk)
• Ongoing: Monitor for:
  • Behavioral response (reduction in inappropriate sexual behaviors)
  • Excessive sedation or cognitive decline
  • New-onset tremor, ataxia, or gait instability
  • Bleeding if on anticoagulants
  • Activation/agitation (though rare, possible early in treatment)

Step 4: Alternative Considerations

If escitalopram fails or is poorly tolerated 5:

• Second-line: Antiandrogens (medroxyprogesterone acetate, cyproterone acetate)
• Third-line: LHRH agonists or estrogens (requires medical clearance)
• Combination therapy: May be needed if monotherapy inadequate

Key Caveats and Pitfalls

Common mistake: Assuming all SSRIs are equivalent. While escitalopram may have slightly lower sexual dysfunction rates in depression treatment 6, 4, 7, this is actually a disadvantage when sexual suppression is the goal. However, its favorable tolerability profile in elderly still makes it reasonable.

Critical warning: The FDA label 2 emphasizes monitoring for suicidal ideation, particularly in the first weeks of treatment, though this patient's age (78) places her outside the highest-risk group (under 24 years).

Drug interaction nuance: While no direct pharmacokinetic interaction exists between escitalopram and antiepileptics, the pharmacodynamic interaction (additive CNS depression) is the primary concern 1.

Sexual dysfunction as therapeutic effect: Unlike typical antidepressant use where sexual side effects reduce quality of life 3, here they're desired. However, monitor for excessive suppression leading to distress if the patient has preserved insight.

Documentation and Consent

Given the off-label use for behavioral management and the three-drug CNS regimen, document:

• Rationale for SSRI use specifically for sexual disinhibition
• Discussion of fall risk and need for environmental safety measures
• Informed consent regarding potential for increased sedation
• Plan for close monitoring and dose adjustment

Bottom line: Proceed with escitalopram 5 mg daily, but implement aggressive fall precautions, monitor sodium levels, and reassess the entire medication regimen for opportunities to simplify if possible. The combination is feasible but requires vigilant management of cumulative CNS effects in this elderly patient.