Q: Although cluster headaches are not usually associated with a significant psychological component, I have heard that mood-stabilizing agents may be effective in preventing such headaches. Which agents are effective – and why?
A: The link between mood disorders and cluster headache is an old one. The cyclical nature of cluster headache and bipolar disorder led to the use of lithium carbonate as a preventive treatment of cluster headache several decades ago.
Lithium in cluster headache prophylaxis: The mechanism by which lithium is effective in cluster headaches is poorly understood. However, it is likely that this agent exerts its effects by altering sodium channels in the nervous system, thereby modifying hyperexcitability of neuronal tissues.
Antiepileptic drugs in cluster headache prophylaxis: Since the late 1980s, multiple reports have suggested that antiepileptic drugs are also effective in cluster headache prophylaxis. Coincidentally, this group of drugs, which includes divalproex and topiramate, has also been studied and shown to be effective in the management of mood disorders and migraine prevention. However, the mechanisms of action of these drugs in headache appear to be substantially different.
Topiramate is a relative newcomer to the treatment of cluster headache. It usually begins to work quickly and may exert benefit during the first week of therapy.
Incremental decreases in dosage of topiramate may be necessary to reduce side effects, such as mental slowing or sedation: these effects are usually not dose-related, but rather are related to the rate of the titration schedule. Overall, such effects are not very common. Paresthesias and altered sense of taste, especially of carbonated beverages, occur more frequently. There are rare reports of acute glaucoma developing at the start of topiramate therapy. Renal stones have also been reported in rare cases associated with long-term use of this agent.
Like divalproex, topiramate works rapidly: a response can often be seen during week 1 or 2 of treatment.