Botox Injection Sites for Migraine Treatment
For chronic migraine treatment, onabotulinumtoxinA (Botox) should be administered across 31-39 specific sites in the head and neck muscles, with a total dose of 155-195 units administered intramuscularly every 12 weeks. 1
Standard Injection Protocol (PREEMPT Paradigm)
The FDA-approved protocol for Botox injections in chronic migraine follows the PREEMPT (Phase III REsearch Evaluating Migraine Prophylaxis Therapy) injection paradigm, which targets specific muscle groups:
Fixed-Site Approach (Core Areas):
- Procerus muscle: 5 units (1 site)
- Corrugator muscles: 10 units (2 sites, 5 units each)
- Frontalis muscles: 20 units (4 sites, 5 units each)
- Temporalis muscles: 40 units (8 sites, 5 units each)
- Occipitalis muscles: 30 units (6 sites, 5 units each)
- Cervical paraspinal muscles: 20 units (4 sites, 5 units each)
- Trapezius muscles: 30 units (6 sites, 5 units each)
Follow-the-Pain Approach (Additional Sites):
- Additional 40 units can be administered using the "follow-the-pain" approach, targeting specific areas where the patient experiences pain 2, 3
- Common additional injection sites include:
- Additional temporal region injections
- Additional occipital region injections
- Additional trapezius muscle injections
Technical Considerations
When injecting in the upper face (glabellar and frontal regions), special attention should be paid to:
- Glabellar region: Inject into the procerus and corrugator supercilii muscles while considering individual facial anatomy to prevent ptosis 3
- Frontal region: Space injections appropriately in the frontalis muscle to avoid excessive forehead immobility 3
- Temporal region: Inject at least 1.5 cm above the orbital rim to avoid complications 3
Efficacy and Dosing Considerations
- The VA/DoD Clinical Practice Guideline provides a "weak for" recommendation for onabotulinumtoxinA injection specifically for chronic migraine (not episodic migraine) 4
- Mayo Clinic notes that onabotulinumtoxinA is FDA-approved for prophylaxis of headache in adults with chronic migraine 4
- Higher doses (195 units) may provide better efficacy than standard doses (155 units) after repeated injections 5
- Treatment response is typically defined as at least 30-50% reduction in headache days 1
Important Caveats
- Botox is not recommended for episodic migraine treatment 4
- Treatment should be administered by clinicians trained in the PREEMPT protocol
- Patients should be monitored for adverse effects including neck pain, muscle weakness, and eyelid drooping 1
- Treatment intervals should remain at 12 weeks to avoid development of antibodies against onabotulinumtoxinA 3
Treatment Outcomes
Studies have demonstrated that Botox treatment can:
- Reduce headache days per month by approximately 56% 2
- Decrease headache intensity by approximately 25% 2
- Provide relief lasting approximately 3-4 months between treatments 6, 7
The standardized PREEMPT injection protocol has been validated in both clinical trials and real-world settings, making it the preferred approach for administering Botox for chronic migraine prophylaxis.