Note to the permanent makeup master: an overview of anesthetics

The ideal local anesthetic should act quickly, effectively and for a sufficiently long time, have low toxicity, do not irritate tissues, withstand sterilization and not be absorbed - remain at the injection site. Unfortunately, there is no single drug that meets all these requirements at once. Each modern local anesthetic has certain disadvantages, which are taken into account when choosing the drug and the method of its use.

Anesthetic groups

According to their chemical nature, local anesthetics are divided into two groups: esters and amides. The main and most commonly used preparations in permanent make-up are:

• esters - Novocaine, Procaine, Anestezin (Benzocaine), Dikain (Tetracaine);
• amides - Lidocaine, Articaine, Melivacaine, Prilocaine, Bupivacaine.

Anesthetics belonging to the "esters" group act for a short time, 30-50 minutes. This is due to the fact that esters are destroyed faster in tissues. The effect of amides lasts longer, from 45 minutes to one and a half hours, and bupivacaine - and more. This is why amide anesthetics are currently used more often than ether ones, since they have a stronger and faster effect, in addition, they provide a large area of anesthesia.

Side effects: local and systemic reactions

Ultimately, local anesthetics still penetrate the tissues and enter the general circulation. It has been clinically proven that the better the drug is absorbed from the injection site, the greater the likelihood of side effects. The latter can be expressed in toxic effects, effects on the central nervous system, cardiovascular system, in the form of local reactions.
Local anesthetics often have side effects, usually a direct toxic effect. Local anesthetics rarely cause anaphylactic reactions.
Local hypersensitivity reactions when using surface anesthetics may manifest as local erythema, urticaria, edema, or dermatitis. When the concentration of local anesthetics in the blood reaches a certain level, systemic effects may appear, that is, an effect on the body as a whole.

Systemic reactions occur rarely and may manifest as generalized erythema, skin rash in the form of blisters and edema, cardiac depression, lowering blood pressure due to vasodilating action, depression or excitation of the central nervous system, and some other symptoms.
Only if the master of permanent makeup has a medical education, it is allowed to use injection anesthesia in his practice! When using injection anesthesia, local complications, first of all, include hematomas that occur at the injection site. Systemic - intravascular administration of the drug.

Although the appearance of a hematoma can be very impressive, it causes a cosmetic inconvenience rather than a health problem. In this case, the application of ice and, if possible, a pressure bandage will help to limit further progression of the edema.
Intravascular administration of the drug is an extremely unpleasant complication due to the direct toxic effect of the local anesthetic and vasoconstrictor on the cardiovascular and nervous systems.

Allergic and non-allergic reactions

Many side effects of local anesthetics, such as swelling at the injection site, arterial hypotension, tachycardia, syncope, occur with both allergic and non-allergic reactions to these drugs.
Among the local anesthetics of the ester group, cross-allergic reactions are often noted. For example, novocaine is slightly toxic, but often causes allergic reactions (dermatitis, angioedema, and even anaphylactic shock). With increased sensitivity to novocaine, the patient experiences dizziness, weakness, lowering blood pressure, collapse, shock. Therefore, when taking an anamnesis, one should pay attention to tetracaine and benzocaine preparations similar in structure, which are part of new drugs that have appeared on our market.
Cross-allergic reactions are also possible between drugs of the amide group, which have a similar structure. There are no cross-reactions between drugs of the 1st and 2nd groups.

According to numerous data, local anesthetics of the amide group are less likely to cause side effects than drugs of the 1st group. Information about the toxicity and anesthetic activity of anesthetics in relation to novocaine, which is used as a standard of strength and toxicity and is taken as a unit, is given in the table (see Fig. 1).

Drug toxicity

Of the ether anesthetics, tetracaine is the most toxic. In terms of its activity and toxicity, it is significantly superior to cocaine. Due to its high toxicity, tetracaine is used only for superficial anesthesia. The drug is easily absorbed, and a slight excess of the therapeutic dose can cause severe intoxication and even death. High toxicity limits the use of this drug.

Benzocaine (anestezin) is also used only for superficial anesthesia of non-inflamed tissues. The FDA (U.S. Food and Drug Administration) in another statement on April 7, 2011 warned the public that benzocaine can lead to a rare disease - methemoglobinemia, and the Veterans Health Administration even announced its decision to withdraw benzocaine spray from practices.
The use of local anesthetics at recommended doses is relatively safe (with the exception of allergic reactions). However, the permanent make-up specialist should always strive to achieve an analgesic effect using the minimum amount of preparation. It is generally recommended to use a dose not exceeding 50% of the maximum toxic dose. Information about the maximum toxic dose is given in the table:

Features of the action of drugs

Each local anesthetic has its own characteristics of action. Basically, in all drugs on the market, there is a combination of short-acting anesthetics (tetracaine, benzocaine) and medium (lidocaine, prilocaine, ultracaine) in terms of duration of action. So, for example, in one of the most powerful pre-action preparations, Super Trio, a combination of three anesthetics is presented: lidocaine - 4%, tetracaine - 2%, benzocaine - 12%.
The use of such a drug is possible only with a clear understanding of the total toxicity and resorption of these anesthetics. It is also necessary to clearly understand that the manifestation of toxicity and activity of the drug on the mucosa is higher than on the skin.
Anesthetics are often combined with adrenergic vasoconstrictors, such as epinephrine, to interfere with or slow down absorption into the bloodstream from the injection site (see table).

The use of anesthesia in conjunction with a vasoconstrictor increases the duration of its action by approximately two or more times. But it must be used very correctly, since adrenaline increases blood pressure, cardiac activity, causes arrhythmia, and dilates the pupils. Very often, patients take the manifestation of a systemic reaction of adrenaline for an allergic reaction to the drug. With the introduction of the drug and a pronounced increase in the pulse, which must be monitored, further administration of the drug must be stopped, and usually a few minutes after the action of the vasoconstrictor, you can work and continue to use the drug.

How to make practice safer

When collecting an anamnesis, we do not always receive truthful information about the state of health of our patients. Specialists are faced with unpredictable situations that threaten the lives of patients (up to the concealment of diagnoses that are contraindications for the permanent makeup procedure).
To protect themselves from legal claims and provide their patient with the maximum level of security, a permanent makeup specialist should know the following:

• Clinically important aspects of the pathogenesis of allergic reactions.
• Differences between true allergic reactions and effects caused by the use of adrenaline.
• Rules for collecting and interpreting anamnesis data.
• Methods of clinical diagnostics.
• Fundamental issues of emergency care in emergency conditions associated with an allergic reaction.
• Own legal aspects.
• Remember that hypoallergenic anesthetics do not exist.

Since the actions of a specialist must be clear, correct and immediate, there should be a package for providing first aid for all options for the development of complications, where the algorithm of sequential actions is clearly spelled out.

Before using local anesthesia, it is necessary to collect the following anamnestic data:
Have you used local anesthesia before?
- were there any complications of local anesthesia;
Have you had any allergic reactions to local anesthetics?
It should be noted that there are currently some studies seeking to prove the safety of local anesthetics, and this topic is actively debated.