What antihistamine is suitable for managing symptoms in dementia or Behavioral and Psychological Symptoms of Dementia (BPSD)?

Antihistamine Selection in Dementia and BPSD Management

For patients with dementia or BPSD requiring an antihistamine, selective serotonin reuptake inhibitors (SSRIs) such as citalopram or sertraline are recommended as first-line options due to their minimal anticholinergic effects, while traditional antihistamines should be avoided due to their anticholinergic properties that can worsen cognitive symptoms. 1, 2

Non-Pharmacological Approaches First

Before considering any medication including antihistamines:

• Establish a predictable daily routine including consistent exercise, meals, and bedtime 2
• Implement the three R's approach (repeat, reassure, redirect) to manage behavioral disturbances 1
• Use cognitive stimulation therapy for mild to moderate dementia 2
• Simplify the environment by reducing excess stimulation, minimizing glare, and reducing noise 2
• Ensure adequate hydration (1.6L daily for women, 2.0L for men) 2

Antihistamine Considerations in Dementia

Avoid Traditional Antihistamines

• First-generation antihistamines (diphenhydramine, chlorpheniramine, hydroxyzine) have strong anticholinergic properties that can:
  • Worsen cognitive impairment
  • Increase confusion and agitation
  • Cause urinary retention
  • Precipitate delirium

Preferred Medications for BPSD with Antihistaminic Properties

1. SSRIs (First Choice)

   • Citalopram or sertraline are preferred due to minimal anticholinergic effects 1
   • Start with low doses and increase slowly
   • Monitor for side effects

2. For Sleep Disturbances/Sundowning

   • Melatonin is recommended as first-line for sundowning due to fewer side effects than benzodiazepines 2

3. For Severe Agitation (When Necessary)

   • Low-dose atypical antipsychotics may be considered for short-term use when there is clear risk of harm:
     • Risperidone: start at 0.25 mg daily at bedtime (max 2-3 mg/day) 2
     • Quetiapine: start at 12.5 mg twice daily (max 200 mg twice daily) 2
   • Important: Use only after non-pharmacological interventions have failed and for shortest duration possible

Monitoring and Assessment

• Reassess cognitive status, functional abilities, and behavioral symptoms every 6 months 2
• Regularly evaluate for depression using simple assessment tools 2
• Monitor for medication side effects, particularly anticholinergic effects
• Assess for drug interactions with existing medications

Caution and Contraindications

• Thioridazine, chlorpromazine, or trazodone should not be used for BPSD 1
• Haloperidol and atypical antipsychotics should not be used as first-line management 1
• After behavioral disturbances have been controlled for 4-6 months, attempt to reduce medication dosages periodically 1
• Some behaviors, such as wandering and pacing, are not amenable to drug therapy 1

Algorithm for Antihistamine Selection in Dementia

1. Determine if an antihistamine is truly needed (allergic reaction, pruritus)
2. If antihistamine is necessary:
   • Choose second-generation antihistamines with minimal CNS penetration (cetirizine, loratadine)
   • Use lowest effective dose
   • Monitor closely for cognitive changes
3. For BPSD symptoms:
   • Start with non-pharmacological approaches
   • If medication is needed, prefer SSRIs over traditional antihistamines
   • Consider melatonin for sleep disturbances
   • Reserve antipsychotics for severe cases with risk of harm

Remember that medications used to treat behavioral disturbances should be periodically reassessed and reduced when possible to determine if continued pharmacotherapy is required 1.