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Botulinum Toxin Injections: 2 Key Factors to Reduce Adverse Outcomes

Every year, more minimally invasive facial aesthetic procedures are carried out all over the globe. The number of nonsurgical injection procedures done in 2017 increased from 2015 by almost 850 000 to over 8.5 million. Botulinum toxin type A (BoNTA) is the most common procedure to be done. Clinical experience with this agent is extensive, and its safety profiles are well characterised. Adverse events (AEs) with BoNTA products are generally transient and mild to moderate in severity. Nevertheless, as the number of complications can be expected to increase with the rising number of procedures performed, clinicians should familiarise themselves with the types of AEs and complications associated with BoNTA products.

The type and frequency of AEs have been well documented in clinical trial publications, product prescribing information and published reviews. In general, overall rates of AEs are similar between BoNTA products, with specific AEs depending, to a certain extent, on the facial treatment area. In the studies' clinical experiences, which is consistent with the literature, the most common AEs associated with BoNTA products are related to injection site reactions, such as mild pain, bruising, tenderness and headache

This article will offer general suggestions for reducing the negative effects of BoNTA products. It is significant to observe that treating patients in conjunction with neuromodulators and fillers is becoming more typical in modern medical aesthetic practice. The placement of filler should come first when using such modalities in the same session, and the more thorough pre- and postcare guidelines for fillers should be observed.

1) Pretreatment Considerations

When using alcohol or chlorhexidine as an antiseptic, caution should be exercised, for they are both extremely irritating to the cornea. Chlorhexidine in particular, when spilled into the eyes, can cause significant chemical burns to the cornea in the form of keratitis. To minimise risks when using chlorhexidine or alcohol, it is important to prevent excess fluid dripping on the conjunctiva or cornea by using dampened, not soaked, gauze or wipes. A safe and effective alternative to chlorhexidine is povidone–iodine. Another proposed option may be a neutral superoxidised agent, such as a product containing hypochlorous acid, which is not deactivated by bacteria.

It is strongly recommended that BoNTA treatment be avoided during pregnancy and breastfeeding owing to the lack of adequate data on the developmental risk to a human foetus from the use of BoNTA in pregnant women and evidence of reproductive toxicity in animal studies. It is also unknown whether botulinum toxin is excreted in human breastmilk.

The general, multisystem medical review preceding treatment with botulinum toxins should document medication usage, allergies, other planned procedures, and previous use of neuromodulator or filler treatments. The evaluation should ascertain whether the patient has conditions for which there are contraindications, warnings or precautions to botulinum toxins, such as known hypersensitivity reactions to botulinum toxin or to any ingredient in the formulation and the presence of infection at the injection site. To reduce the risk of bruising and ecchymosis, it may be helpful for patients to avoid nonessential over‐the‐counter medications or supplements (e.g. fish oil and vitamin E oil) that may affect blood clotting for approximately 1 week before treatment. We suggest that one week is sufficient for stopping nonessential aspirin and other nonsteroidal anti‐inflammatory drug use.

Patient counselling is essential in a number of ways. Patients may need to be informed that facial aesthetic injections are medical procedures and should be taken carefully given their popularity and overall safety. Patients should receive advice on what to report during and after treatment in this respect. In our clinical experience, the most frequent AEs associated with BoNTA treatment are mild pain, tenderness, and stinging; however, patients should immediately inform clinicians of any posttreatment event that is bothersome or does not go away. These may include uncommon adverse reactions, such as eyelid or eyebrow ptosis, and inadvertent alteration of the smile by paresis of muscles, such as the zygomaticus major or minor, depressor labii or risorius.

Some of these complications can be corrected with injection of BoNTA in muscles that antagonise the affected muscles; in the case of eyelid ptosis, ophthalmic solutions with alpha‐adrenergic effects, such as naphazoline 0.025%/pheniramine 0.3% or apraclonidine 0.5%, may be used to elevate the upper eyelid via contraction of the Müller muscle

Table 1 shows the summary for Pretreatment evaluation:

2) Post-treatment Recommendations

Written post-treatment directions should be given to patients, along with details on how to get in touch with the office if they have any questions after business hours. For patients getting BoNTA treatments for the first time or in a new treatment area, we advise scheduling a follow-up visit two weeks after treatment.

Patients may resume normal activities after 4 hours. There is no need to move, or avoid moving, the affected muscles. Some practitioners recommend contracting the treated muscles to facilitate uptake of the product, but this is not necessary. When fillers are used in combination with BoNTA, patients should be advised to follow posttreatment instructions appropriate to their filler treatment.

Table 2 shows the summary for Posttreatment Recommendations:


Injectable BoNTA has well‐established safety profiles. The majority of adverse reactions are transient, self‐resolving and mild to moderate in severity. Many of these events are injection‐related rather than product‐related. Nevertheless, with the continually increasing popularity of minimally invasive facial treatments with neuromodulators and soft‐tissue fillers, clinicians are likely to encounter a greater frequency of rare but serious complications. It is therefore important for clinicians to be fully cognisant of all potential complications, to employ known prevention strategies and to be able to undertake appropriate remedial treatment. Thorough knowledge of anatomy and careful injection techniques are fundamental to achieving optimal outcomes. Owing to the widespread popularity and overall favourable safety profiles of neuromodulator and filler treatments, patients may not appreciate that sometimes serious complications can arise. Comprehensive patient counselling and education are also integral steps in aesthetic practice.


Facial Aesthetic Injections in Clinical Practice: Pretreatment and Posttreatement Consensus Recommendations to Minimise Adverse Outcomes (2020)

Safety of botulinum Toxin A in Aesthetic Treatments: A Systematic Review of Clinical Studies (2014)

Facial Aesthetics: Is Botulinum toxin treatment effective and safe? A systematic Review of Randomised Controlled Trials (2009)

Injectibles and topical neurotoxins in dermatology: Indications, Adverse Events, and controversies (2017)


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