Head & neck · Clinician education
Learn the regimen, examine the anatomy, and reason through preparation, injection and follow-up.
Edited by Dr. Meredith Barad
Lesson 1 of 7
Explain what must be established before treatment, and give a balanced account of likely benefit and possible harm.
OnabotulinumtoxinA is a preventive treatment for adult chronic migraine. The US label specifies at least 15 headache days per month, with headache lasting at least four hours a day. Frequency alone does not establish a complete migraine diagnosis: review the headache phenotype, diary, examination, differential diagnosis, acute medication use and prior preventive treatment.
Label §1.3; trial eligibility and baseline diary methods.
Assess resting eyelid and brow position, asymmetry and compensatory frontalis activity. Ask about neck pain, weakness, swallowing difficulty and respiratory problems. Observe neck posture and muscle function.
2017 pp. 775–776; 2023 p. 852; label §§5.5–5.6.
Hypersensitivity to a botulinum toxin preparation or its components, and infection at a proposed injection site, are label contraindications. Neuromuscular disorders and pre-existing swallowing or breathing difficulties require additional risk assessment. Review interacting medicines and recent therapeutic or aesthetic toxin treatments across providers. Pregnancy has limited human safety data; do not describe it as established safe use.
Label §§4–5.6, 7 and 8.1.
Confirm chronic migraine and review headache days, acute medication use, disability and previous preventive treatment. Record baseline eyelid position, facial and neck function, and swallowing vulnerability before comparing later benefit or adverse effects. A treatment map does not establish the diagnosis.
Label §§1.3, 2.5, 5; Blumenfeld 2017 examination guidance.
Discuss the likely benefit, the treatment burden, and what to do if symptoms arise.
Scale: 0–10 days · Week 24
1.8 additional headache days reduced, on average, versus placebo.
Mean reduction from baseline at week 24. Higher bars indicate a larger reduction, not the number of headache days remaining. Pooled randomized population: 688 active, 696 placebo. The pooled report contains the same participants as PREEMPT 1 and 2.
| Event | BOTOX | Placebo |
|---|---|---|
| Neck pain | 9% | 3% |
| Muscular weakness | 4% | <1% |
| Eyelid ptosis | 4% | <1% |
| Injection-site pain | 3% | 2% |
BOTOX 155–195 U, n=687; placebo, n=692. Rates are per trial participant. Label Table 19; definitions differ from the pooled paper’s treatment-related-event table.
Difficulty swallowing is explicitly included in counseling. It was listed among potentially related events occurring in fewer than 1% of BOTOX-treated chronic-migraine trial participants and more often than placebo; the exact rate was not provided.
New swallowing, speech or breathing difficulty requires immediate medical evaluation. Symptoms can appear hours to weeks after injection. Use the local emergency pathway.
Discuss hypersensitivity and the boxed warning for effects beyond the injection site, including generalized weakness and swallowing or breathing problems. Pre-existing neuromuscular, swallowing or respiratory impairment can increase concern.
Discuss repeated visits, multiple injections, procedural discomfort, the possibility of inadequate benefit and other appropriate preventive options. Retreatment is recommended every 12 weeks.
Needle breakage is a separate mechanical risk. Do not bend 30G needles or straighten and use damaged ones.
Use the viewer’s own navigation and skin controls. Select a dot on the image.
Preparing the original reference images…
Illustrations and animations: imagegen and MiniMax H3 Max. Appearance references: Ultimate Full Body Anatomy Collection. Anatomy references: Z-Anatomy (CC BY-SA 4.0), BodyParts3D (CC BY-SA 2.1 Japan), and University of Dundee CAHID (CC BY 4.0).
The examination animations combine generated muscle movement with authored skin-reveal effects and captions.
Z-Anatomy license