Lithium — Preventative Treatment Overview

Lithium (usually prescribed as lithium carbonate) is a mood stabiliser most commonly used to treat bipolar disorder. However, it also has a long history of use as a preventative treatment for cluster headache, especially chronic cluster headache (CCH).

It is one of the main second-line preventatives, particularly when verapamil alone isn’t enough.


What Lithium Is

  • Originally developed for bipolar mood stabilisation
  • Has strong effects on brain signalling and circadian rhythms
  • Well-studied in neurology and psychiatry
  • Used off-label in headache medicine for chronic cluster headaches

Because lithium stabilises the brain’s internal timing systems (and CH is tightly tied to the hypothalamus), it can reduce attack frequency in many chronic CH patients.


How Lithium Works

Lithium affects multiple brain pathways, including:

  • Modulating serotonin signalling
  • Influencing the hypothalamus and circadian rhythms
  • Reducing overactive neuronal firing
  • Increasing GABA activity (a calming neurotransmitter)

Cluster headache has strong links to the brain’s “body clock,” so lithium’s stabilising effect on circadian biology may explain its usefulness.


Evidence for Use in Cluster Headache

Lithium is one of the most established treatments for chronic cluster headache, with decades of clinical use.

Research and clinical experience show:

  • Many chronic CH patients improve on lithium
  • Attack frequency can drop significantly
  • It is often combined with verapamil for greater effectiveness
  • Some episodic CH patients benefit, but episodic cases usually respond better to verapamil alone

Lithium is not suitable for everyone due to monitoring requirements, but for the right patient, it can be life-changing.


Typical Dosing (Neurologist-guided only)

Lithium requires careful, personalised dosing.

Typical approach:

  • Start low (e.g., 300 mg once or twice daily)
  • Adjust based on response
  • Target blood levels of 0.4–0.8 mmol/L for CH (lower than bipolar treatment)

Lithium must be increased slowly, and blood tests determine the correct dose — not symptoms alone.


Monitoring & Safety

Lithium has a narrow therapeutic range, meaning the difference between “effective” and “too much” is small.

Regular monitoring is essential:

  • Lithium blood levels
  • Kidney function
  • Thyroid function
  • Electrolytes (especially sodium levels)

Monitoring typically occurs:

  • Before starting
  • 1 week after each dose change
  • Then every 3–6 months

Staying well-hydrated is important, as dehydration can increase lithium levels.


Common Side Effects

Lithium can cause side effects, especially early on or at higher doses.

Common effects include:

  • Tremor (especially hands)
  • Increased thirst
  • Frequent urination
  • Nausea
  • Diarrhoea
  • Fatigue
  • Weight gain (varies by person)
  • Cognitive slowing or mild memory issues

Side effects often improve with dose adjustments.

More serious risks include:

  • Kidney impairment
  • Thyroid dysfunction
  • Toxic lithium levels if dehydrated or interacting medications are added
  • Heart rhythm changes in susceptible patients

This is why ongoing monitoring is essential.


Who Should Avoid Lithium

Lithium may not be appropriate for people with:

  • Kidney disease
  • Thyroid disorders
  • Heart conduction issues
  • Severe dehydration risk
  • Pregnancy or planning pregnancy
  • Significant fluid/electrolyte instability
  • Use of certain interacting medications (e.g., NSAIDs, diuretics, ACE inhibitors)

Lithium interacts with many common medicines, so all other prescriptions must be checked.


Summary

Lithium is a long-established preventative medication for chronic cluster headache, often effective when other treatments fail. It helps stabilise the brain’s circadian rhythms and reduces overactive nerve signalling. However, it requires regular blood tests, careful dosing, and close supervision due to potential side effects and interactions.

Best suited for:
Chronic CH patients, or those who did not respond well to verapamil alone.

Not usually the first choice for episodic cluster headache.