Magnesium Bisglycinate for Periodic Limb Movements in Sleep (PLMS)
There is insufficient evidence to recommend a specific dose of magnesium bisglycinate for treating periodic limb movements in sleep (PLMS), as no FDA-approved treatments exist specifically for PLMS and current guidelines do not support routine pharmacologic treatment for this condition. 1
Understanding PLMS and Treatment Approach
PLMS is characterized by:
- Repeated rhythmical extensions of the big toe and dorsiflexions of the ankle with occasional flexions of the knee and hip 1
- Movements typically lasting 2-4 seconds occurring approximately every 20-40 seconds 1
- Movements that may cause brief awakenings or arousals from sleep 1
- Diagnostic criteria requiring >15 events per hour in adults or >5 events per hour in children 1
Current Treatment Recommendations
Evidence Against Routine Treatment
- The American Academy of Sleep Medicine (AASM) guidelines state there is very little evidence to support pharmacologic treatment to suppress PLMS, even with insomnia or hypersomnia 1
- No agent has been FDA-approved specifically to treat PLMS or PLMD 1
First-Line Approaches
- Address any underlying conditions that may be causing or exacerbating PLMS 1
- Evaluate for restless legs syndrome (RLS), as 90% of individuals with RLS have PLMS 1
- Consider discontinuation of medications that may worsen PLMS, particularly antidepressants 1
Magnesium for PLMS
Limited Evidence
- One open pilot study showed that oral magnesium (12.4 mmol in the evening) over 4-6 weeks decreased PLMS associated with arousals significantly (from 17±7 to 7±7 events per hour) 2
- However, a 2019 systematic review concluded that there is insufficient evidence to determine the effectiveness of magnesium for RLS/PLMD 3
Potential Mechanism
- Lower serum magnesium levels have been associated with higher PLMS index in population-based studies 4
- Magnesium may help with muscle relaxation and neuromuscular function 2
Clinical Considerations
When to Consider Magnesium
- May be considered as a complementary approach when:
Important Caveats
- Parental reports of leg movements in children correlate poorly with objective PLMS measurements (sensitivity 50%, specificity 51%) 6
- A high PLMS index does not necessarily correlate with symptom severity or treatment response 5
- PLMS without clinical sleep disturbance should be reported as a polysomnographic finding but does not meet criteria for PLMD diagnosis 1
Conclusion
While some clinicians recommend magnesium supplementation for PLMS based on anecdotal evidence and limited research, there is insufficient high-quality evidence to recommend a specific dose of magnesium bisglycinate. If considering magnesium, the dose used in the only published pilot study was 12.4 mmol in the evening 2, but this should not be considered a standard recommendation due to the low quality of evidence.