Botox Treatment for Migraine

Although many people only know of Botox because of its multiple mentions in the popular press and magazines as a treatment for frown lines and wrinkles, its is a very unusual drug in that it has multiple potential uses – with over 90 different cited indications now published  in clinical papers.
Botox has been used as a treatment for migraines for many years – although this has been restricted to “off license” use until recently when Botox received a UK license in 2010.

Although it doesn’t help everyone - our experience at MediZen in the use of Botox injections for the treatment of migraine has shown it to be an effective and safe treatment for chronic migraine. Over the last few years many of the people that we have treated have tried different drug or complementary medicine treatments, but their migraines were still having a significant impact on their quality of life.

Clinical Studies

A number of different studies have been published examining the evidence for the effectiveness of Botox as a preventative treatment for migraine, including the PREEMPT study which was the main supporting trial for the license application. 

The PREEMPT (Phase III REsearch Evaluating Migraine Prophylaxis Therapy) clinical programme which consisted of two phase III studies both of which were randomised, double-blind and placebo controlled enrolling over 1,300 patients diagnosed with chronic migraine.

In these studies, patients were given either BOTOX® injections or placebo injections for 24 weeks, then all patients received BOTOX® until the end of the 56 week study.

The results of these studies are consistent across multiple headache symptom measures, including headache days and quality of life. These studies show that BOTOX® is significantly better than placebo in reducing the number of headache days, migraine days and improving functioning, vitality and overall health related quality of life.


Key Facts about BOTOX® for chronic migraine from the PREEMPT programme:

  • At baseline, patients in the BOTOX® treatment group had an average of 19.1 days with migraine. Patients in the placebo group had an average of 18.9 migraine days. Following treatment with BOTOX® patients had an average of 8.2 fewer migraine days at week 24, which was significantly greater than the change from baseline observed in placebo treated patients (6.2 days);
  • Patients treated with BOTOX® had significantly fewer headache days compared to those patients treated with placebo (47.1% of BOTOX® treated patients compared to 35.1% of placebo treated patients achieved >50% reduction from baseline in the number of headache days at the week 24 primary timepoint).
  • At the end of the second phase of the trial (week 56), nearly 70% of patients treated with BOTOX® experienced >50% reduction from baseline in migraine days;
  • Patients treated with BOTOX® experienced improvements in their ability to complete normal everyday activities as well as a reduction in their sense of frustration and helplessness.

The conclusion from the PREEMPT programme is that BOTOX® is a generally well-tolerated and effective prophylactic (preventative) treatment for adults with chronic migraine:

Throughout the PREEMPT trials including the open label phase, patients received up to 5 courses of treatment with BOTOX® every 12 weeks. Most adverse events reported in the trials were mild to moderate and resolved without further problems. The discontinuation rate was low in both treatment arms; 3.8% in the BOTOX® treated arm and 1.2% in the placebo arm.

How does Botox work for the treatment of Migraine?


This is the "science bit", so don't worry if you don't understand! – but according to Allergan Limited, the manufacturers of Botox, the presumed mechanism for migraine headache prophylaxis with Botox injections is by blocking peripheral signals to the central nervous system, which inhibits central sensitisation, as confirmed by clinical and non-clinical studies.

Clinical evidence suggests that Botox reduces or prevents local neuropeptide (NP) release and thus reduces NP-induced sensitisation of peripheral nociceptive (pain-conducting) nerve fibres, thereby reducing peripheral pain signals to the central nervous system.
Additionally, Botox preferentially targets Cfibres and probably TRPV1-receptors, block neurotransmitter release and subsequently reduces pain, neurogenic inflammation and cutaneous heat pain thresholds.

These hypotheses regarding the proposed mechanism of action for prevention of headaches in chronic migraine are also supported by non-clinical data.

Botox is typically injected in the glabella (in the muscles that cause furrows between the eyes), temples, forehead, and sometimes the masseters (jaw muscles), occipital muscles, neck muscles and upper trapezius (shoulders).

It is really important to understand that the treatment of migraine needs to be tailored accurately to the individual, and may also vary in an individual from session to session. Dose of Botox used varies from 60-100 units or more depending on factors such as number of trigger points, size of muscles, sex and so on. The technique requires a detailed knowledge of anatomy and is not something that should be offered other than by a doctor specifically trained in the treatment of migraine with Botox.