A Practical Approach to Botulinum Toxin Injections

Injection with botulinum toxin has been the most commonly performed minimally invasive procedure for the past 20 years. In 2022, more than 8.7 million botulinum toxin procedures were performed in the United States. Currently, five botulinum toxin formulations are approved by the US Food and Drug Administration (FDA).

Botulinum toxin injections are well known for cosmetic use, with specific FDA approval for treating wrinkles in the frontal lines, glabellar lines, lateral orbicularis oculi lines (also known as crow’s feet), and platysma bands of the neck. Botulinum toxin injections improve dynamic wrinkles that occur with muscle contraction and are less effective for wrinkles apparent at rest. This differential effect is related to the mechanism of action of botulinum toxin, which relaxes muscles by inhibiting acetylcholine release.

Other FDA-approved indications for botulinum toxin injections include overactive bladder with urinary incontinence due to a neurological condition, chronic migraine headache prophylaxis, upper limb spasticity, cervical dystonia, hyperhidrosis, blepharospasm, and strabismus. A Cochrane review found that botulinum toxin injections for chronic migraine prophylaxis reduce headaches by 2 to 3 days per month.

Potential adverse effects of botulinum toxin injections include ecchymosis and other injection-related effects, allergic reactions (less than 0.1%), headache, paresthesia or dysesthesia (less than 1%), unintended muscle relaxation (eg, blepharoptosis, eyebrow ptosis, facial asymmetry), antibody formation against botulinum toxin (less than 1%), and botulinum-like effects (occurs rarely and typically with high doses used for therapeutic purposes).

Contraindications or precautions to injection with botulinum toxin include body dysmorphic disorder, neurological disorders (including gross motor weakness in treatment area and neuromuscular conditions), immunocompromise, pregnancy, breastfeeding, allergy to components of the injection, history of keloid formation, infection or dermatoses in treatment region, and those whose job depends on facial expressiveness (eg, actors). Additionally, botulinum toxin injections should be used with caution in patients taking medications that affect neuromuscular signaling, such as muscle relaxants.

Additional information on botulinum toxin injections may be found in an American Family Physician article on botulinum toxin procedures. Hands-on training courses for botulinum toxin injections are recommended before offering the procedure for patients. Courses are available through many conferences and organizations, including the American Academy of Procedural Medicine.