Injection therapy (PBS-Approved Nerve Blocking Therapy)

If you suffer from chronic migraines, are over 18 years of age, not pregnant, breastfeeding or planning for a pregnancy in the next 3 months you should consider injection therapy. You should also consider the therapy if at least 3 preventative medications provided from your doctor have limiting side effects or have been unable to provide you with significant benefit.

Injection therapy is generally well tolerated. The precise location and quantity of each injection has been tested extensively for safety and effectiveness. A brief stinging sensation can be produced at each injection site. In a small percentage of patients, (3-9%), neck pain, headaches, heaviness of the brow and or eyelids can be experienced, however these are all temporary should they occur.

It may take 4 weeks after the injections to notice a benefit, although some patients may see an improvement sooner. In some patients a benefit may not be seen until after their second injection series. After the injections patients are able to drive home and resume normal activities. Vigorous neck exercises, neck massage, and or physiotherapy are however discouraged for 24 hours after the procedure.

There is good evidence that when it works, injection therapy has a cumulative effect, with better and better response with each cycle administered every 3 months across a year. However after 2 injection cycles, as per PBS criteria, if no improvement is noticed, the injections should be discontinued.

Injection therapy is not a cure for migraines, it does however represent an effective preventative intervention in many migraine patients.

Injection therapy (PBS-Approved Nerve Blocking Therapy) has been subject of several well conducted trials, as well as ongoing clinical reviews, with the following outcomes achieved:

  • It is effective for chronic migraine, with a 70% response rate after 3 injection cycles1
  • A significant reduction in severe migraine events is seen in treatment responders, with a 90% reduction in emergency department visits2
  • Significant improvements in headache related disability, resulting in significantly improved functioning, vitality and overall Headache related Quality of Life Assessments can be achieved3
  • Compliance with migraine prophylactic medications is a major issue, with the need to consume an oral medication every day, or sometimes 2 to 3 times per day. Convenience is superior in this regard with injection therapy, with the injection cycles administered every 12 weeks
  • Patients receiving injection therapy also had significantly fewer intakes of triptans (acute therapy), than did placebo groups

Injection therapy (CGRP blocking therapy)

A new, first of its kind injectable treatment for the prevention of migraine in adults has been approved in Australia. The medication is a calcitonin gene related peptide (CGRP) receptor blocker.

CGRP is a neurotransmitter associated with the development of migraine. CGRP levels have been shown to increase significantly during a migraine and return to normal with migraine relief. This new injectable treatment works specifically by blocking the activity of the CGRP molecule.

The drug was evaluated for prevention of both chronic and episodic migraine in two separate randomised, multi-centre, placebo-controlled, double blind studies. For many patients, the medication was shown to reduce the number of monthly migraine days versus placebo and in some patients cut monthly migraine days by 50% or more.4, 5

Improvements were seen within four weeks of commencing treatment with the medication. The drug is also efficacious in patients who had previously failed prophylactic migraine treatment due to lack of efficacy or intolerance and in patients with a history of medication overuse.

A favourable adverse effect profile was seen from the pivotal trials, with no major side effects apparent. A few mild adverse events for the therapy have been reported however, including injection site reactions, constipation, muscle spasms and itchy skin.

Thus far, these drugs have shown no major side effects when given to patients, although potential problems of blocking CGRP on a long term basis, if any, are not yet known, and further observation will be required.


  1. Percent of patients with chronic migraine who responded per ‘injection therapy’ treatment cycle, Silberstein et al PREEMPT JNNP; 2015 Sep;86(9):996-1001.
  2. Experience with ‘injection therapy’ with chronic refractory migraine: focus on severe attacks, Oterino etc et al, J Headache Pain 2011 Apr;12(2):235-238
  3. ‘Injection therapy’ for Treatment of Chronic Migraine, Aurora et al, Headache 2011;51(9);1358-1373
  4. A Controlled Trial of Erenumab for Episodic Migraine, Goadsby et al, N Engl J Med, 2017; 377: 2123-32
  5. Safety and Efficacy of Erenumab for preventative treatment of chronic migraine: a randomized, double-blind, placebo-controlled phase 2 trial , Tepper et al, Lancet Neurol 2017; 16:425-34
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