Definition
Local anesthetics are drugs for local anesthesia. They are therefore called local anesthetics, but they must not be confused with the active ingredients that fall under the narcotics law and include opioids. These are strong painkillers, most of which are associated with the development of an addictive potential. Local anesthetics are used to inhibit the transmission of pain and are therefore used in numerous invasive procedures on the body.
At the dentist
Local anesthesia is often used in dentistry to perform outpatient procedures without pain. A distinction is made between surface anaesthesia, infiltration anaesthesia, conduction anaesthesia and intraligamentous anaesthesia. In surface anaesthesia, an anaesthetic is applied to the mucous membrane.
Infiltration anesthesia is more invasive, as the local anesthetic is injected into the gums with a syringe. With conduction anesthesia, a whole nerve tract and thus all nerves emanating from it are blocked and the aim of intraligamentary anesthesia is to anesthetize a specific tooth. In some cases, before the injection of the local anesthetic, the affected area of the mucous membrane is superficially anesthetized by syringe to reduce the puncture pain.
This prevents the fear of injections or the fear of the dentist in general. There are also painless injection techniques. Before the drug is injected, the dentist checks by aspiration with the syringe (aspiration test) that he has not accidentally punctured a vessel. If this would be the case, a new syringe must be used, because injection into a blood vessel can lead to cardiovascular problems.
Side effects
As mentioned above, local anesthetics also act on sodium channels in the heart and central nervous system, provided that their dose is high enough. This can happen by choosing a too high dose or by incorrect application. For example, by mistakenly injecting the local anesthetic into a vein (intravenously).
It can also happen that during epidural anaesthesia the cannula is pushed too far forward and ends up in the subarachnoid space. Since the dose of the drug is higher in epidural anesthesia than in spinal anesthesia, this can also lead to serious side effects. The heart can be affected by cardiac arrhythmia, in the worst case by cardiac arrest.
In the central nervous system, local anesthetics lead to hyperexcitability. At the beginning this can manifest itself for example as tingling around the mouth (perioral), slurred speech, restlessness, dizziness, tremor or nervousness and anxiety. The maximum form is seizures, which can lead to respiratory arrest. In addition, the use of a local anesthetic can lead to allergic reactions up to the maximum form, anaphylactic shock. However, the amide-type substances that are used much more frequently nowadays have hardly any allergenic potency, so that the risk of intolerance is to be classified as rather low.
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