While there have as yet been no double-blind, placebo-controlled studies proving the effectiveness of Botox as a treatment for severe chronic migraine, Botox may well be one of the best preventive treatments for severe chronic migraine sufferers. This opinion is based on a number of small controlled trials combined with a large number of anecdotal reports, and extensive clinical observation.
A person with chronic migraines is defined as having headaches at least 15 days out of the month, with actual migraine symptoms at least 8 days a month. In one clinic, over the course of 13 years, nearly 2,000 patients were treated with Botox, and it is estimated that, of those, 60-70% got relief from Botox. Many of those had tried multiple other therapies to no avail.
One of these patients was a 76 year old woman who had endured migraines for 60 years. After dozens of different medications, nerve blocks, and other therapies, she saw a neurologist, who recommended Botox. After a single treatment, she experienced three months of total relief from her migraines.
One of the most interesting things about Botox is that it is quite safe. This is probably due to the fact that it is a local injection, rather than a systemic treatment like medication, and that it is used in minute doses. Botox is used for so many different conditions that it has been used in millions of times in the past 20 years. Botox is a bit pricy, but studies have shown that it actually reduces healthcare costs in migraine patients, not to mention the costs attributed to time off work and reduced productivity.
Recent reports have raised concerns regarding FDA review of the safety of Botox. It is important to note that the safety issues were related to two very specific groups of patients. The first group was children with cerebral palsy who received Botox to treat spasticity. There is a concern that they could receive too many doses leading to system toxicity. The second group of concern is patients who were treated with Botox for torticollis, a condition where tightened or spastic neck muscles prevent normal head movement, who developed trouble swallowing.
There was also a case of an unlicensed practitioner who injected himself and three others with a dose 3,000 times higher than normal with commercial grade botulinum toxin. All victims spent several months on a respirator, but ultimately recovered.
Though generally safe, Botox is just like any other drug in that it does carry some risk of side effects. Most side effects are temporary and usually mild. These include worsening of pain immediately after the injections, bruising, redness, and undesirable cosmetic outcomes (such as mismatched eyebrow height). Injections in the trapezius muscles can lead to a collapsed lung, and injections in the neck muscles can cause weakness requiring a soft collar temporarily. Most side effects, especially the more serious ones, are generally avoidable through proper technique.
While it is possible to have an allergic reaction to Botox, severe reactions are extremely rare, probably because the dosage is so minute. The typical dose for treating headaches is only 5 nanograms, or 5 billionths of a gram. For those not familiar with the metric system, there are more than 28 billion nanograms in an ounce.
Myobloc, another botulinum toxin product, is available, but with some disadvantages. It has a very low pH (is quite acidic), so injections are more painful. It takes effect a little faster, but doesn’t last quite as long as Botox. The risk of it spreading beyond the treated area is also higher, increasing the risk of muscle weakness near the treated area. Despite the disadvantages, in those rare instances when a patient develops antibodies to Botox, Myobloc may still be effective.
It is important that Botox only be used in patients who have undergone thorough evaluation. It is important to rule out factors that may be contributing to headaches, such as too much caffeine, too little magnesium, or hypothyroidism, as eliminating contributing factors may be sufficient to offer relief. Then, triptans or other therapies, including medication, exercise, nutrition, and supplements should be tried. Anticonvulsant medication or a β-blocker may also be considered prior to Botox.
Botox has not been approved for use in women who are pregnant or breastfeeding, but is appears to be safer than many other migraine medications, many of which are also not approved. Just because it isn’t approved does not mean pregnant women cannot receive Botox. Many have, and with excellent results.
After so many years of using Botox for so many different conditions, why have there not been more studies to prove the safety and efficacy of Botox? There are a couple of reasons.
One of the biggest reasons is the difficulty in conducting double-blind trials of injectable medications because placebos produce a response so frequently. While there have been a number of small trials that support the efficacy of Botox in treating chronic migraines, large studies have failed to reduce the number of headache free days. However, when patients using prophylactic medications are eliminated, the difference becomes more significant. This difference clarifies why it is important to exclude patients on prophylactic medications from migraine trials.
Another trial was poorly designed because the injections were only given in the front of the head. In that study, patients given 25 units of Botox showed improvement, while those receiving 75 units did not. It is possible that patients with strictly frontal headaches were more concentrated in the lower dose group than in the higher dose group.
Two other medications, topiramate (Topamax) and gabapentin (Neurontin), have proven moderately effective, but have not received FDA approval for migraine treatment.
There is some concern that Botox has become a popular treatment due to higher reimbursement rates by insurance companies than some other treatments. While a valid concern, nerve blocks are also reimbursed at a high rate, without gaining the popularity that Botox has achieved.
Another round of trials in progress will hopefully persuade the FDA of the safety and efficacy of Botox for chronic migraines.