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Benzocaine – Effect, Application & Risks


Benzocaine is a drug from the drug class of local anesthetics . The drug is mainly used in local pain therapy in the area of ​​the skin and mucous membranes .

What is benzocaine?

Benzocaine, like lidocaine and procaine , is a local anesthetic. Local anesthetics have a local effect and reversibly reduce the excitability of sensory nerve fibers . The drug is an ester-type anesthetic. Benzocaine blocks the sodium channels on the nerve cells and thus prevents the transmission of stimuli.

The drug is mainly used as a surface anesthetic. With topical anesthesia, the local anesthetic is applied to the mucous membrane or the skin. The sites of action are the ends of the sensitive nerves . With surface anesthetics, small interventions in particular should be kept pain-free. Sprays, powders, ointments, suppositories and solutions are available as possible application forms.

Pharmacological action

Benzocaine is a sodium channel blocker. The sodium channels play an important role in the transmission of stimuli. In the nervous system , the stimulus is transmitted in the form of electrical impulses. Every body cell has a so-called membrane potential . In nerve cells, this is called the resting potential . The resting potential is around -60 mV. It arises from the fact that there is an excess of potassium ions inside the cell and an excess of sodium ions outside the cell. Potassium ions are more negatively charged than sodium ions. Therefore, at rest potential, the inside of the cell is negatively charged compared to the outside.This balance is maintained by the sodium-potassium pump . Only potassium ions enter the cell through them. When a stimulus hits the nerve cell, voltage-gated sodium channels in the membrane open, allowing an influx of sodium ions. The cell depolarizes , the membrane potential rises briefly to +30 mV. This state is also known as an action potential . The action potential is carried from nerve cell to nerve cell via the nerve fibers until the target cell is reached and the desired reaction is triggered.

Sodium channel blockers like benzocaine suppress this process. They prevent the influx of sodium into the cell, so that there is no depolarization and therefore no action potential. In the case of benzocaine, there is no sensory perception in the area of ​​skin supplied by the corresponding nerve. If an area of ​​skin is numbed with benzocaine, pain perception is no longer possible.

Medical Application & Use

The drug is mainly used for local anesthesia in the area of ​​the skin and mucous membranes. The preferred application site is the mouth and throat area . Benzocaine is found in many cold medicines. Also (over-the-counter) lozenges for sore throats or teething problems often contain benzocaine.

Benzocaine can also be taken to treat stomach pain . Cough-suppressing drug preparations also often contain the local anesthetic drug. Creams, solutions and powders are used, for example, to relieve the pain of corns , athlete’s foot , calluses and warts .

Benzocaine suppositories are also available. These are used for rectal anesthesia for hemorrhoids or other anal conditions such as anal eczema or anal itching .

Benzocaine can also be used as a delay cream. For this, the drug is applied to the glans of the penis. The numbing effect is said to reduce sensations in the genital area to prevent premature ejaculation . Before the beginning of the sexual act , the remedy should be applied to the glans with the foreskin pulled back. Stunning begins after just one minute. It subsides after 10 to 15 minutes. Also some condomsare mixed with benzocaine. There is a small amount of benzocaine ointment in the reservoir of these special condoms. The warmth of the penis dissolves the ointment and desensitizes the area. Due to the small dosage and the uneven distribution, however, the desired effect is often not achieved.

Risks & side effects

Benzocaine contains a so-called para primary aromatic amino group. The para groups have a significantly higher allergic potential than non-para-substituted local anesthetics such as lidocaine. In case of intolerance, allergic reactions can occur on the skin . Red, brownish or white patches can form on the affected skin areas. Fluid-filled blisters , purulent pustules or wheals may appear . The skin is red and warm. It may hurt or itch. Benzocaine can cause stomach pain when taken orally.A rare side effect is the so-called methemoglobinemia , in which there is an increased level of methemoglobin in the blood . From a content of 20 percent, there are signs of a lack of oxygen supply. These include symptoms such as headaches , confusion and skin turning blue . Coma may develop with severe methemoglobinemia . However, this state can only be achieved with very high doses of benzocaine.

Lisa Newlon
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Hello! I am Lisa Newlon, and I am a medical writer and researcher with over 10 years of experience in the healthcare industry. I have a Master’s degree in Medicine, and my deep understanding of medical terminology, practices, and procedures has made me a trusted source of information in the medical world.