Products
Botulinum toxin is commercially available as an injectable. It has been approved in many countries since 1994. The drugs contain a dried preparation reconstituted with sterile physiological saline (sodium chloride 0.9%).
Structure and properties
Botulinum toxin type A is the toxin of the anaerobic and gram-positive bacterium . Various products are commercially available, which differ, among other things, in the production, protein content and size of the protein complex. To identify the different active ingredients, the following names have been introduced:
- Onabotulinumtoxin (e.g., Botox).
- Abobotulinumtoxin (e.g. Azzalure).
- Incobotulinumtoxin (e.g., Bocouture) – without complex proteins.
The active neurotoxin is a protein with a molecular weight of about 150 kDa, which may be present complexed with other atoxic proteins (e.g., hemagglutinin). In some products, the complex proteins have been removed. The neurotoxin consists of a heavy and light chain linked by a disulfide bridge.
Effects
Botulinum toxin (ATC M03AX01) inhibits the presynaptic release of the neurotransmitter acetylcholine from cholinergic nerve terminals, blocking neuromuscular stimulus transmission at the motor endplate. It causes “chemical denervation” and thus inhibits muscle contractions. On skeletal muscle, this results in flaccid paralysis. The effect is delayed within a few days and usually lasts three to six months.
Mechanism of action
Botulinum toxin cleaves the protein SNAP-25 (synaptosomal-associated protein 25 kDa), preventing the binding and release of acetylcholine from vesicles in presynaptic nerve terminals. SNAP-25 plays a central role in exocytosis.
Indications
For the temporary treatment of facial wrinkles, e.g., vertical wrinkles between the eyebrows (glabellar wrinkles, “frown lines”) and “crow’s feet” (canthal wrinkles). In addition, there are also various medical indications. This article refers to wrinkle treatment.
Dosage
According to the professional information. The drug is injected intramuscularly at various points with a fine needle.
Contraindications
- Hypersensitivity
- Infection or inflammation at the intended injection sites
- Generalized disorders of muscle activity, such as myasthenia gravis, Eaton-Lambert syndrome, or amyotrophic lateral sclerosis.
- Pregnancy and lactation
Full precautions can be found in the drug label.
Interactions
Drug-drug interactions are possible with aminoglycosides, drugs that affect neuromuscular conduction, anticholinergics, and antithrombotics.
Adverse effects
The most common possible adverse effects include local reactions at the injection site such as redness, irritation, rash, itching, and pain, as well as headache. Other common adverse reactions include:
- Eye discomfort
- Drooping of the upper eyelids
- Swelling of the eyelids
- Eye tears
- Dry eyes
- Muscle twitching around the eyes
- Facial paralysis, “Frozen Face”.
Very rarely, severe to life-threatening side effects are possible (anaphylaxis, local spread of toxicity).
