Erenumab relieves trigeminal neuralgia – another case series

Trigeminal neuralgia (TN) is an extremely painful and often debilitating condition. Many people respond to the standard therapy with epilepsy drugs such as carbamazepine (Tegretol) or oxcarbazepine (Trileptal). Botox injections can be helpful as well. A significant minority of patients, however, do not respond to these treatments and sometimes require brain surgery.

Fortunately, we have a new class of drugs that has allowed some of my patients to avoid having an operation. These drugs are CGRP monoclonal antibodies (mAbs). They have been approved by the FDA only for the prevention of migraine headaches, so their use for TN is considered to be “off-label”.

The first case series was reported in 2019 by the Cleveland Clinic doctors. They found that six out of eight TN patients had a good response to erenumab (Aimovig).

A group of Israeli physicians published another case series in the current issue of Neurology. They found that nine out of ten TN patients obtained very good relief from erenumab.

Erenumab was the first CGRP mAb. It was approved in May of 2018. Another two, galcanezumab (Emgality) and fremanezumab (Ajovy) were approved about six months later. These are given by a monthly subcutaneous injection. About a year ago, an intravenous CGRP mAb, eptinezumab (Vyepti) was also approved. These four drugs are very similar. However, some patients find one to be more effective than others. I’ve found this to be true not only in migraine patients but also in those with TN. Erenumab is slightly different in its mechanism of action and it is the only one that has a warning about the potential for causing severe constipation and increased blood pressure. Since TN patients tend to be older and more prone to these side effects, I prefer galcanezumab or fremanezumab. Unlike eptinezumab, they can be self-administered.

Off-label use is totally legitimate. However, insurance companies are not likely to pay for an expensive drug that is not explicitly approved by the FDA for a specific indication. And these drugs are not cheap – about $600 to $700 for each monthly shot. Because of the competition among pharmaceutical companies, they provide us with plenty of free samples (except for eptinezumab). TN is a relatively rare disorder so we can provide free samples to all of our TN patients who respond to these drugs. This is true for most neurologists’ private offices. This may not be true in big hospitals where sampling is not allowed.