Botulinum toxin type A (Botox, Allergan) is a purified neurotoxin complex, which is derived from the bacterium Clostridium botulinum. It has neuromuscular transmitter blocking effects. Botox® (onabotulinum toxin A) is licensed specifically for the treatment of chronic migraine. Botox® has not been shown to be effective for any other headache type (e.g. episodic migraine, tension-type headache, cluster headache) as yet.
Botox injections can provide sustained pain relief in patients with chronic migraine headaches. NICE (The National Institute for Health and Care Excellence) has recommended considering botox treatment in patients who have not responded to prophylactic drugs and other conservative management. However it is important to note that in some cases injection treatment may not provide the desired results or the pain relief may not be sustained. At Pain Spa Dr Krishna is very experienced in interventional treatments, including botox injections for patients suffering from chronic migraines.
Botulinum toxin type A is recommended as an option for the prophylaxis of headaches in adults with chronic migraine (defined as headaches on at least 15 days per month of which at least 8 days are with migraine):
Treatment with botulinum toxin type A should be stopped in people whose condition: is not adequately responding to treatment (defined as less than a 30% reduction in headache days per month after two treatment cycles) or has changed to episodic migraine (defined as fewer than 15 headache days per month) for three consecutive months.
Two Phase 3 Research Evaluating Migraine Prophylaxis Therapy (PREEMPT) trials recruited 1384 patients with chronic migraine, and randomised them to treatment with Botox® or placebo. These patients were suffering on average 20 days of headache each month, of which 18 were moderate or severe. Those randomised to Botox® received fixed-site, fixed dose injections every 12 weeks over 56 weeks. These injections covered seven specific areas of the head and neck, with a total dose of between 155-195 units. At six months, after two cycles of treatment, those treated with Botox® had on average eight less days of headache each month. After 12 months, 70% of those treated had ≤50% the number of headaches that they had done originally. Botox® was well tolerated, the commonest side effects being neck pain (6.7%), muscular weakness (5.5%), and drooping of the eyelid (3.3%). No serious irreversible side effects have ever been reported in trials of Botox® in headache.
Botox injections should generally avoided in patients with systemic infection or skin infection over puncture site, bleeding disorders or coagulopathy and allergy to botulinum toxin.
Botox is generally contraindicated in patients with pre-existing neuromuscular disorders (peripheral motor neuropathic diseases, amyotrophic lateral sclerosis, myasthenia gravis or Lambert-Eaton syndrome). Patients with neuromuscular disorders may be at increased risk of clinically significant effects including severe dysphagia and respiratory compromise from therapeutic doses of botox.
Botox injections for migraine are performed on a day case basis. The recommended reconstituted dose is 155–195 units, administered intramuscularly as 0.1 ml (5 units) injections to between 31 and 39 sites around the head and back of the neck. The recommended re-treatment schedule is every 12 weeks.
Patients should be aware that the outcome of the procedure is variable and they may not receive the desired benefits. Similarly, they must be aware of the transient nature of the therapeutic benefits and that there may need repeated injections.
Complications are rare. Possible complications include bruising, infection, hematoma, nerve injury and reaction to the injectates. Infection can be avoided with appropriate aseptic precautions. Severe allergic reactions to botulinum toxin are uncommon. Side effects include rash, neck pain, myalgia, musculoskeletal pain, musculoskeletal stiffness, muscle spasms, muscle tightness, muscular weakness, facial paresis, eyelid ptosis, pruritus and injection site pain.
At Pain Spa Dr Krishna is very experienced in interventional treatments, including botox injections for patients suffering from chronic migraines.