63 Botulinum Toxin & Fillers Flashcards
What is botulinum toxin and what is its mechanism of action?
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.
What are the formulations of botulinum toxin that are available in the United States?
What are the formulations of botulinum toxin that are available in the United States?
There are currently three FDA-approved formulations of BTX-A:
- Botox and Botox Cosmetic (onabotulinumtoxinA, Allergan, Irvine, CA)
- Dysport (abobotulinumtoxinA, Valeant, Laval, Quebec)
- Xeomin (incobotulinutoxinA, Merz, Frankfurt, Germany)
Botox and Xeomin have an equivalent strength of activity per unit. Dysport has less strength per unit, and it takes on average 2 to 3 units of Dysport to equal the strength of 1 unit of Botox.
The only BTX-B formulation available is Myobloc (rimabotulinumtoxinB, Solstice Neurosciences, Louisville, KY).
What is botulinum toxin used for?
What is botulinum toxin used for?
From a cosmetic standpoint, Botox Cosmetic, Dysport, and Xeomin 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.
From a medical standpoint, Botox, Dysport, and Xeomin also have FDA approval for the treatment of cervical dystonia. Botox and Xeomin are also approved for the treatment of blepharospasm. Botox, because it has been around the longest and has the longest record of safety, is also FDA approved for the treatment of strabismus, upper limb spasticity, chronic migraines, urinary incontinence in patients with overactive bladder due to neurologic disease, and severe primary axillary hyperhidrosis.
Other common off-label uses for botulinum toxin include facial tics, spasmodic dysphonia, myofascial pain syndrome, and sialorrhea.
What is the onset and duration of botulinum toxin?
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.
What is the lethal dose of Botox and what is a common dose for cosmetic purposes?
What is the lethal dose of Botox and what is a common dose for cosmetic purposes?
The LD50 (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.
What are typical doses of Botox for facial rhytids?
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 cm above eyebrow
- Crow’s feet: 8–12 units on each side divided in 3–4 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
What are the depressors and elevators of the brow?
What are the depressors and elevators of the brow?
- Depressors: corrugators supercilii, procerus, depressor supercilii (part of the orbicularis muscle), procerus
- Elevators: frontalis
What is the “Mr. Spock” look and how do you treat it?
What is the “Mr. Spock” look and how do you treat it?
The “Mr. Spock” look is caused by excessive elevation of the lateral brow while the medial brow remains relatively fixed. The look is due to overactivity of the lateral aspect of the frontalis and is easily treated by injecting botulinum toxin in that area to weaken its activity.
What is a chemical brow lift?
What is a chemical brow lift?
Botox is injected in the superolateral orbicularis oculi muscle just below the eyebrow to weaken the orbicularis oculi’s depressor function. This results in a 1 to 2 mm elevation of the brow.
What are some common side effects of botulinum toxin?
What are some common side effects of botulinum toxin?
Pain and bruising at the injection site are most common. Headache, dry mouth, tiredness, neck pain, and eye problems can also occur.
What are some serious potential side effects of botulinum toxin?
What are some serious potential side effects of botulinum toxin?
Serious, potentially fatal, side effects include difficulty breathing, difficulty swallowing, dysphonia, dysarthria, loss of bladder control, and generalized weakness. This is most likely due to spread of the toxin from the injection site to other parts of the body. At usual cosmetic doses, these side effects are very unlikely.
How does eyelid ptosis occur after botulinum toxin injection and how do you treat it?
How does eyelid ptosis occur after botulinum toxin injection and how do you treat it?
Ptosis occurs by diffusion of the botulinum toxin to the levator palpebrae superioris or levator aponeurosis, usually by injection of botulinum toxin too close to the upper eyelid. It can best be prevented by injecting at least 1 cm above the orbital rim.
Apraclonidine (Iopidine) and phenylephrine (Mydfrin) eye drops will selectively target α2 and α1 adrenergic receptors, respectively, leading to contraction of Müller muscle which will decrease the ptosis.
Can a patient be resistant to botulinum toxin?
Can a patient be resistant to botulinum toxin?
Yes. While rare, there are reports of patients developing resistance to botulinum toxin. This is felt to be due to the formation of antibodies either to the neurotoxin or the complexing proteins that accompany it. To avoid this possibility, it is recommended to use the smallest possible doses to achieve the desired effect and to wait at least 3 months between treatments.
What precautions should patients take after botulinum toxin injection?
What precautions should patients take after botulinum toxin injection?
The patient should avoid massaging or rubbing the injected areas as well as any skin treatments on the day of the procedure. Additionally, the patient should avoid any vibrational therapy such as the whirlpool or hydrotherapy. The patient ideally should avoid vigorous sports for a week after injection.
What are some different types of fillers available for facial aesthetics?
What are some different types of fillers available for facial aesthetics?
Broadly, fillers can be classified as absorbable or nonabsorbable. The only nonabsorbable filler available is Artefill (Suneva Medical, San Diego, CA), composed of polymethylmethacrylate microspheres. Its use has largely fallen out of favor due to the widespread success of absorbable fillers.
Absorbables can be divided into synthetic or natural products. Synthetic fillers include Radiesse (Merz, Frankfurt, Germany), composed of calcium hydroxylapatite and Sculptra (Valeant, Laval, Quebec), composed of poly-L-lactic acid.
Natural absorbable fillers account for the most commonly used facial fillers, with hyaluronic acid (HA) products comprising the bulk of this category. Other options include autologous fat and collagen, but collagen products are no longer used due to superiority of the HA products and fat.
What are different methods of injection of facial fillers?
What are different methods of injection of facial fillers?
- Serial puncture: Injecting a series of small boluses
- Threading: Tunneling the needle beneath the area of concern and injecting as the needle is withdrawn
- Fanning: Injection of multiple threads radially by changing direction without withdrawing the needle
- Crosshatching: Injection of multiple threads perpendicular to one another in a grid
Threading is useful for lip and nasolabial fold augmentation. Fanning and crosshatching are particularly useful for filling in larger defects.
