Why does dental anesthetics contain adrenaline? Precious information for those who fear of anesthesia

Most dental procedures are performed under anesthesia. But many people are afraid of anesthesia, one of the myths related to this being that the adrenaline could be bad for them. Here are some explanations about the use of the anesthetic-adrenaline combination that will make you understand how it acts on the body.


The anesthetic acts locally, blocking nerve conduction by reducing the influx of sodium ions into the neuronal cytoplasm. If sodium does not enter the neuron, the potassium ion cannot come out, inhibiting nerve depolarization and thus anesthesia occurs. The most used dental anesthetic is xylin. This leads to vasodilation, increasing the blood volume in the area of administration. For this reason, xylin is administrated in combination with a vasoconstrictor, such as adrenaline. Practically, adrenaline causes a diameter reduction of local blood vessels and, thus, the increase  the duration of anesthetic agent metabolism. In other words, anesthesia takes longer.


Adrenalina este un hormon secretat in organism si este cunoscut ca „hormonul lupta sau fugi”. Daca intra in circulatia generala, poate creste ritmul cardiac, pacientul devenind usor agitat. Anxietatea poate speria anumite persoane, insa efectul este de scurta durata si nu este periculos.

Adrenaline is a hormone produced in the body and is known as “fight-or-flight” hormone “. If it enters the general circulation, it can increase the heart rate, making the patient slightly agitated. Anxiety can frighten some people, but the effect is short-lived and it is not dangerous.


However, there are contraindications. In patients with heart problems or those who are taking antidepressants or synthetic thyroid hormones, another anesthetic drug, namely mepivacaine, will be administrated. That is why the dentist will ask you every time if you have such problems and it is necessary to be sincere when giving the answers.

Dr. Andreea Bedreaga

Dentist, Smilemed Clinic

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