Does hydroxyzine worsen REM (Rapid Eye Movement) behavior disorder in patients taking simvastatin?

Hydroxyzine Does Not Worsen REM Behavior Disorder in Patients Taking Simvastatin

Hydroxyzine is not known to worsen REM behavior disorder in patients taking simvastatin, and there is no evidence in current clinical guidelines suggesting such an interaction.

Understanding REM Behavior Disorder (RBD)

REM Behavior Disorder is characterized by:

• Loss of normal REM sleep muscle atonia
• Complex behavioral manifestations during dreams
• Potential for sleep-related injuries to patient or bed partner
• Often associated with neurodegenerative diseases (particularly synucleinopathies)

Medications Known to Affect RBD

Medications That Can Worsen or Induce RBD:

• Serotonergic antidepressants (SSRIs) 1
• Monoamine oxidase inhibitors 2
• Tricyclic antidepressants 2
• Noradrenergic antagonists 2

Medications Used to Treat RBD:

1. First-line treatments:

   • Clonazepam (0.25-2.0 mg before bedtime) 1
   • Melatonin (starting at 3 mg, can increase to 15 mg) 1, 3

2. Second-line or adjunctive treatments:

   • Rivastigmine (for patients with RBD and cognitive impairment) 1

Hydroxyzine and RBD

Hydroxyzine is an antihistamine with sedative properties commonly used for anxiety and as a sleep aid. Based on the available clinical guidelines:

• Hydroxyzine is not listed among medications known to induce or worsen RBD 1, 2
• There is no documented interaction between hydroxyzine and simvastatin that would specifically affect RBD symptoms
• Hydroxyzine does not have significant serotonergic activity (unlike SSRIs which are known to potentially worsen RBD) 1

Simvastatin Considerations

Regarding simvastatin:

• Statins (including simvastatin) have shown no excess toxicity in patients with impaired kidney function or on dialysis 1
• There is no evidence in the guidelines suggesting that simvastatin affects RBD symptoms or interacts with RBD treatments 1

Clinical Management Approach

For patients with RBD who are taking simvastatin and considering hydroxyzine:

1. Assess RBD severity and current management:

   • Document frequency and intensity of dream enactment behaviors
   • Evaluate risk of sleep-related injuries

2. Consider first-line RBD treatments:

   • Clonazepam (0.25-2.0 mg before bedtime) 1
   • Melatonin (3-15 mg before bedtime) 1, 3

3. Implement safety measures:

   • Remove potentially dangerous objects from bedroom
   • Consider padding around bed or sleeping on mattress on floor
   • Separate sleeping arrangements if bed partner safety is a concern 1

4. Monitor for treatment response:

   • Be aware that depression may negatively impact treatment response 4
   • Some degree of dream enactment may persist despite treatment 1

Conclusion

Hydroxyzine can be used in patients with RBD who are taking simvastatin, as there is no evidence suggesting this combination worsens RBD symptoms. If sleep medication is needed in a patient with RBD, melatonin may be preferable as it has both sleep-promoting effects and can help manage RBD symptoms 1, 3.