Trigeminal neuralgia is a rare form of headache that is typically treated with antiseizure medication. Now a new study reveals that this treatment increases the risk of ischaemic stroke and Alzheimer’s disease.
Most people do not know much about trigeminal neuralgia because this kind of headache, which affects the whole face, is very rare.
In Denmark, 5,000 people have trigeminal neuralgia, which is typically treated with antiseizure drugs such as carbamazepine and oxcarbazepine. A new study reveals that this treatment increases the risk of ischaemic stroke.
According to a researcher behind the study, the results should lead to slightly better monitoring of risk factors for ischaemic stroke among people with trigeminal neuralgia who take these two drugs.
“The dilemma is that these two drugs can increase the risk of ischaemic stroke but are also the most effective for individuals with trigeminal neuralgia. This study therefore implies that neurologists should improve the monitoring of people with trigeminal neuralgia, especially if they have a higher cardiovascular risk profile,” explains Thomas Folkmann Hansen, Associate Professor, Danish Headache Center, Rigshospitalet, Copenhagen, Denmark.
The study, with Jacob Worm as the first author, has been published in Pain.
Data on 7.2 million people
The researchers examined Denmark’s national health registers using advanced models (the Danish Disease Trajectory Browser) to identify the other diagnoses people had received before and after their trigeminal neuralgia diagnosis.
Data on 7.2 million residents of Denmark from 1994 to 2018 were obtained from the Danish National Patient Register, and the results revealed that 18 other diagnoses often preceded a diagnosis of trigeminal neuralgia – with nine other diagnoses often following.
Some of these diagnoses such as for back pain, musculoskeletal disorders and multiple sclerosis were often known to precede a diagnosis of trigeminal neuralgia.
However, the scientific literature has not similarly described any diagnoses that increase the risk of ischaemic stroke and Alzheimer’s occurring more often among individuals diagnosed with trigeminal neuralgia compared with the rest of the population.
In fact, these people had a 55% increased risk of stroke.
Medication increases the risk of stroke
In addition, the researchers investigated genetic data from the Copenhagen Hospital Biobank, which contains information on more than 200,000 people, to determine whether the risk of ischaemic stroke resulted from some people already having genes that increase the risk of stroke.
Trigeminal neuralgia could heighten the risk among people who already had a higher genetic risk of stroke, but the researchers were able to reject this possibility.
Finally, the researchers investigated whether the medication individuals with trigeminal neuralgia took could explain the increased risk of ischaemic stroke.
This part of the study was carried out using data from Denmark’s Register of Pharmaceutical Sales, which registers the consumption of medication in Denmark by monitoring the purchase of prescribed drugs.
The researchers found that the individuals studied who took carbamazepine and oxcarbazepine for trigeminal neuralgia had a 78% increased risk of stroke. However, no similar risks were found for other medicines.
The researchers also found that the increased risk of stroke among people with trigeminal neuralgia who stopped using the two drugs declined to the same level as the background population six months after stopping.
“Our research clarifies that these two drugs increase the risk of ischaemic stroke among people with trigeminal neuralgia. Six drugs are used to treat trigeminal neuralgia, but only these two are associated with an increased risk of stroke. Unfortunately, they are also the most effective,” says Thomas Folkmann Hansen.
New drugs needed
Thomas Folkmann Hansen says that the study does not show that individuals with trigeminal neuralgia taking carbamazepine or oxcarbazepine should stop using them.
However, both doctors and patients should be aware when these drugs are used and check blood pressure, cholesterol level and other ischaemic stroke risk factors a little more often.
“Unfortunately, we do not have good substitutes for carbamazepine and oxcarbazepine for these people, but we hope that some drug manufacturers may be attracted to the idea of developing new medication that is not associated with the same stroke-related risk. In addition, investigating why these drugs are associated with an increased risk of stroke may be relevant – especially because other people use these drugs to treat pain,” concludes Thomas Folkmann Hansen.
