letibotulinumtoxinA

Action and Spectrum

Actions and Spectrum: 

Actions: 

LETYBO functions by inhibiting the release of the neurotransmitter acetylcholine from peripheral cholinergic nerve endings, resulting in a flaccid paralysis of muscles. The sequence of events involved is, binding of the toxin to the specific surface receptors on nerve endings, mediated by heavy chain, followed by internalization through receptor-mediated endocytosis. Subsequently, the light chain present in toxin undergoes translocation to the cell cytosol that is pH-induced, this leads to the cleavage of SNAP25 and the intracellular blockage of acetylcholine exocytosis into the neuromuscular junction. This mechanism forms the basis for its therapeutic application in conditions characterized by excessive efferent activity in motor nerves. The recovery of transmission occurs gradually as the neuromuscular junction rebounds from SNAP25 cleavage and new nerve endings are formed. 

Spectrum: 

Botulinum toxin A generally possesses cosmetic applications in wrinkle reduction, contour correction, and face lifting depending on the response of the patient. 

Drug Interaction

Adverse Reaction

Frequency not defined 

Periorbital hematoma 

Pruritus 

Pain 

Swelling at the site of administration 

Folliculitis 

Facial pain 

Hematoma 

Bruising at the site of injection 

Reaction 

Nodule 

Mass 

Frequency defined 

1-10% 

Headache (2%) 

<1% 

Blepharospasm 

Eyelid ptosis 

Brow ptosis 

Black Box Warning

Black Box Warning: 

Reactions at the site of injection may occur due to effect of toxins 

Contraindication / Caution

Contraindication/Caution: 

Contraindications 

Hypersensitivity 

Infection at the site of injection 

Cautions 

Not interchangeable with other botulinum toxin products. 

Serious adverse reactions, including dysphagia, excessive weakness, and aspiration pneumonia may occur 

Serious and immediate hypersensitivity reactions, such as anaphylaxis. 

Cardiovascular adverse effects, including myocardial infarction and arrhythmia. 

Risk of transmission of CJD (Creutzfeldt-Jakob disease) and viral diseases 

Caution should be exercised in patients with facial alterations, scarring, dermatochalasis, asymmetry, or inflammation. 

Careful administration is necessary in cases of excessive weakness or atrophy in target muscles. 

Potential ophthalmic effects, including dry eye and corneal disorders. 

Increased risk of significant effects in patients with neuromuscular disorders. 

Potential spread of toxin effects beyond the injection site. 

Risk of dyspnea and dysphagia, with potential respiratory failure. 

Caution with anticholinergic drugs, aminoglycosides, and concurrent use of other botulinum neurotoxin products and muscle relaxants. 

Pregnancy / Lactation

Pregnancy consideration:  

Safety study about the use of letibotulinumtoxinA in pregnancy is not available. 

Breastfeeding warnings:  

Data about the excretion of letibotulinumtoxinA into human milk is not known 

Pregnancy categories: 

Category A: well-controlled and satisfactory studies show no risk to the fetus in the first or later trimester. 

Category B: there was no evidence of risk to the fetus in animal studies, and there were not enough studies on pregnant women. 

Category C: there was evidence of risk of adverse effects in animal reproduction studies, and no adequate evidence in human studies must take care of potential risks in pregnant women.    

Category D: adequate data with sufficient evidence of human fetal risk from various platforms, but despite the potential risk, and used only in emergency cases for potential benefits.    

Category X: Drugs listed in this category outweigh the risks over benefits. Hence these categories of drugs need to be avoided by pregnant women.    

Category N: No data is available for the drug under this category. 

Pharmacology

Pharmacology: 

LetibotulinumtoxinA is a neurotoxin derived from Clostridium botulinum. It is used to treat facial spasmodic disorders. 

Pharmacodynamics: 

Botulinum neurotoxin leads to muscle-weakness in a dose-dependent manner by blocking the release of acetylchline from the pre-synaptic vesicles irreversibly. 

Pharmacokinetics: 

Limited data is available 

Adminstartion

Administration: 

To prepare for intramuscular (IM) administration, reconstitute with 0.9% NaCl (preservative free) to achieve a 4 units/0.1 mL solution. Ensure the reconstituted product is clear and colorless before administering within 24 hours. Refrigerate unused product for up to 24 hours. 

For IM administration, carefully assess the upper eyelid and follow guidelines to reduce ptosis risk. Avoid injection near the levator palpebrae superioris, ensure accurate volume, and administer steadily. Discard any unused medication. 

Patient Information Leaflet

Patient information leaflet 

Generic Name: letibotulinumtoxinA 

Pronounced: leh-te-boh-too-lin-um-tock-sin-A 

Why do we use letibotulinumtoxinA? 

LetibotulinumtoxinA is administered into muscles to provide temporary enhancement of moderate to severe glabellar lines (brow furrows) in adults. These lines are commonly linked to the activity of the corrugator and/or procerus muscles.