Physical Address

304 North Cardinal St.
Dorchester Center, MA 02124

Botulinum Toxin and Fillers


Key Points

  • 1.

    Of the botulinum toxins available, Botox® has the longest record of safety and efficacy as well as the most FDA-approved indications. However, due to similar mechanism of action and widespread off-label use, Dysport®, Xeomin®, and Jeuveau® may also be used for cosmetic purposes.

  • 2.

    Hyaluronic acid–based fillers are the most commonly used facial fillers.

  • 3.

    Major adverse reactions to injection with facial fillers are rare and can largely be prevented through meticulous technique and injection into the correct plane.

Pearls

  • 1.

    Botulinum toxin cleaves SNAP-25 at the presynaptic neuromuscular junction, inhibiting acetylcholine release. This leads to temporary muscle paralysis.

  • 2.

    Upper eyelid ptosis secondary to botulinum toxin injection can be treated with alpha-2 adrenergic ophthalmic drops.

  • 3.

    An understanding of a filler’s rheologic and physicochemical properties, such as G′, helps the clinician select which products are the most suitable for a given clinical need.

  • 4.

    Sculptra® acts by invoking a host tissue response that leads to the gradual ingrowth of type I collagen.

Questions

1

What is botulinum toxin and what is its mechanism of action?

Clostridium botulinum produces botulinum exotoxin (BTX), of which there are seven serotypes (A-G). These potent neurotoxins cause flaccid paralysis by preventing the release of acetylcholine from presynaptic vesicles at the neuromuscular junction. This is accomplished by cleaving the SNARE complex of proteins (SNAP-25, synaptobrevin, and syntaxin) that allows the vesicles containing acetylcholine to fuse with the plasmalemma of the nerve terminal, leading to exocytosis. By preventing muscle contraction, BTX prevents the formation of facial rhytids from dynamic muscle movement.

2

What are the formulations of botulinum toxin that are available in the United States?

There are currently four FDA-approved formulations of BTX-A:

  • Botox and Botox Cosmetic (onabotulinumtoxinA, Allergan, Irvine, CA)

  • Dysport (abobotulinumtoxinA, Valeant, Laval, Quebec)

  • Xeomin (incobotulinumtoxinA, Merz, Frankfurt, Germany)

  • Jeuveau® (prabotulinumtoxinA-xvfs, Evolus, Santa Barbara, CA)

  • The only BTX-B formulation available is Myobloc (rimabotulinumtoxinB, Solstice Neurosciences, San Francisco, CA).

3

What is botulinum toxin used for?

From a cosmetic standpoint, Botox Cosmetic, Dysport, Xeomin, and Jeuveau are all FDA approved for the temporary improvement of glabellar lines. Botox Cosmetic also has an additional cosmetic indication for the temporary improvement of lateral canthal lines, otherwise known as crow’s feet. Use of these products in other locations for aesthetic purposes is considered off-label.

Other medical indications include the following:

  • 1.

    Botox®: overactive bladder, detrusor overactivity due to a neurologic condition, chronic migraine, upper and lower limb spasticity, cervical dystonia, axillary hyperhidrosis, blepharospasm, and strabismus

  • 2.

    Dysport®: cervical dystonia, upper and lower limb spasticity

  • 3.

    Xeomin®: chronic sialorrhea, upper limb spasticity, cervical dystonia, and blepharospasm

  • 4.

    Jeuveau®: no medical FDA-approved indications

Other common off-label uses for botulinum toxin include facial tics, spasmodic dysphonia, myofascial pain syndrome, and sialorrhea.

4

What is the onset and duration of botulinum toxin?

For cosmetic injections in the face, it takes 3 to 7 days for the effects of botulinum toxin to be seen, reaching maximal efficacy around 2 weeks after injection. This effect lasts for approximately 3 months. However, with repeated injection, the duration could extend to 4 to 6 months as the facial muscles atrophy. The return of normal muscle function occurs through axonal sprouting and production of new neuromuscular junctions.

5

What is the lethal dose of Botox and what is a common dose for cosmetic purposes?

The LD 50 (lethal to 50% of those injected) is 2500 to 3000 units in humans. For cosmetic purposes, use of 40 to 60 units per treatment is common.

6

What are typical doses of Botox® for facial rhytids?

  • Glabella: 20–40 units divided in 5 sites

  • Forehead: 10–30 units divided in 4–8 sites; inject at least 2 centimeters above the eyebrow

  • Crow’s feet: 8–12 units on each side divided in 2–4 sites

  • Perioral area: 4–10 units divided in 2–6 sites

  • Chin: 2–8 units divided in 1–2 sites

  • Neck (platysmal banding): 10–40 units divided in 2–4 sites per band

7

What are the depressors and elevators of the brow?

  • Depressors: corrugator supercilii, procerus, depressor supercilii (part of the orbicularis muscle)

  • Elevator: frontalis

These muscles are demonstrated in Fig. 65.1 .

Fig. 65.1, Depressors and elevators of the brow.

8

You're Reading a Preview

Become a Clinical Tree membership for Full access and enjoy Unlimited articles

Become membership

If you are a member. Log in here

Related Posts