benzocaine oropharyngeal

Action and Spectrum

Actions and Spectrum: 

• benzocaine is a local anesthetic commonly used in oropharyngeal preparations such as throat lozenges and sprays. It is a member of the ester-type local anesthetics and acts by reversibly blocking nerve impulses in the affected area. 
• The benzocaine’s action mechanism involves its ability to inhibit the conduction of nerve signals by blocking voltage-gated sodium channels on the neuronal membrane. When applied topically, benzocaine diffuses into the nerve endings and binds to these sodium channels, preventing the influx of sodium ions required to generate and propagate action potentials. As a result, the nerve’s ability to transmit pain signals to the brain is temporarily halted, leading to a local anesthetic effect. 
• benzocaine primarily acts on the surface tissues, relieving pain and discomfort in the oropharyngeal area. It is commonly used to alleviate sore throat, mouth ulcers, teething pain, and other mouth and throat conditions. The spectrum of activity of benzocaine is limited to the site of application and does not have a systemic effect. 

Drug Interaction

Adverse Reaction

Frequency not defined 

Contact dermatitis 

Pruritus 

Stinging 

Burning 

Erythema 

Rash 

Tenderness 

Black Box Warning

Black box warning: 

None 

Contraindication / Caution

Contraindications/caution: 

Contraindications: 

• Hypersensitivity or Allergy: Individuals with known hypersensitivity or allergy to benzocaine or other ester-type local anesthetics should avoid using benzocaine oropharyngeal products. Allergic reactions can range from mild skin irritation to severe reactions such as difficulty breathing, swelling, or anaphylaxis. 
• Methemoglobinemia: benzocaine has the potential to cause methemoglobinemia, a condition in which the blood is unable to transport oxygen effectively. Individuals with a history of methemoglobinemia or those with a deficiency of the enzyme glucose-6-phosphate dehydrogenase (G6PD) should avoid benzocaine oropharyngeal products. 
• Infants Younger than 2 Years: benzocaine products should not be used in infants younger than 2 years old, particularly those at risk of developing methemoglobinemia. This includes infants with a family history of methemoglobinemia or those who have previously experienced it. 
• Severe Sore Throat or Swallowing Difficulties: If you have a severe sore throat or difficulty swallowing, it is essential to consult a healthcare professional before using benzocaine oropharyngeal products. These symptoms may indicate a more serious underlying condition that requires medical evaluation and treatment. 
• Open Wounds or Infections: benzocaine should not be applied to open wounds or infected areas in the oropharyngeal region. It is intended for topical use on intact mucous membranes and may interfere with wound healing or worsen existing infections. 
• Porphyria: benzocaine may exacerbate symptoms of porphyria, a group of rare genetic disorders that affect the production of heme, a component of hemoglobin. If you have porphyria or a family history of the condition, consult a healthcare professional before using benzocaine oropharyngeal products. 

Caution: 

• Duration of Use: benzocaine oropharyngeal products are intended for short-term use to provide temporary relief. Prolonged or excessive use can lead to local irritation, sensitivity reactions, or other adverse effects. If symptoms persist or worsen after using benzocaine, it is essential to seek medical advice. 
• Avoid Ingestion: benzocaine products should not be ingested or swallowed. They are specifically designed for topical use in the mouth and throat. Ingestion of benzocaine can lead to systemic absorption and may increase the risk of adverse effects, especially methemoglobinemia. 
• Pediatric Use: While benzocaine can be used in older children under appropriate supervision, it is generally not recommended for infants and young children, especially those under 2 years of age. Young children’s immature metabolic and detoxification systems may increase the risk of methemoglobinemia. 
• Drug Interactions: benzocaine oropharyngeal preparations may interact with certain medications. 
• Pre-existing Medical Conditions: Individuals with certain medical conditions, such as asthma, bronchitis, or chronic obstructive pulmonary disease (COPD), may be at an increased risk of developing adverse effects from benzocaine oropharyngeal products.  
• Allergic Reactions: While rare, allergic reactions to benzocaine can occur. If you experience itching, rash, swelling, or difficulty breathing symptoms after using benzocaine, discontinue and seek immediate medical attention. 

Pregnancy / Lactation

Pregnancy consideration: C 

Lactation: Excretion of the drug in human breast milk is unknown 

Pregnancy category: 

Category A: well-controlled and Satisfactory studies show no risk to the fetus in the first or later trimester. 

Category B: there was no evidence of risk to the fetus in animal studies, and there were not enough studies on pregnant women. 

Category C: there was evidence of risk of adverse effects in animal reproduction studies, and no adequate evidence in human studies must take care of potential risks in pregnant women.    

Category D: adequate data with sufficient evidence of human fetal risk from various platforms, but despite the potential risk, and used only in emergency cases for potential benefits.    

Category X: Drugs listed in this category outweigh the risks over benefits. Hence these categories of drugs need to be avoided by pregnant women.    

Category N: There is no data available for the drug under this category 

Pharmacology

Pharmacology: 

• Methemoglobinemia: benzocaine has been associated with the risk of methemoglobinemia, a condition characterized by an abnormal form of hemoglobin that cannot transport oxygen effectively. benzocaine can oxidize hemoglobin, converting it to methemoglobin, which is less efficient at binding and releasing oxygen. methemoglobinemia can result in cyanosis (bluish discoloration of the skin and mucous membranes) and potentially compromise oxygen delivery to tissues.  
• Local Irritation and Sensitivity: In some cases, benzocaine can cause local irritation, sensitivity reactions, or allergic responses in individuals. Symptoms may include itching, redness, swelling, or a rash in the oropharyngeal area. It is important to discontinue use and seek medical attention if such reactions occur. 
• Local Anesthetic Action: benzocaine acts as a reversible local anesthetic by blocking nerve impulses in the area where it is applied. It works by inhibiting the function of voltage-gated sodium channels in the neuronal membrane. By binding to these channels, benzocaine prevents the influx of sodium ions into the nerve cells, thereby reducing or inhibiting the generation and conduction of nerve impulses. 
• Onset and Duration of Action: benzocaine has a relatively rapid onset of action when applied topically to the oropharyngeal mucosa. It provides temporary pain relief by numbing the affected area. The duration of action can vary but is generally limited, requiring reapplication as needed for continued relief. 

Pharmacodynamics: 

• Nerve Conduction Inhibition: By blocking sodium channels, benzocaine inhibits nerve fibers’ depolarization and subsequent repolarization, preventing the propagation of pain signals along the nerves. This interruption of nerve conduction temporarily reduces the sensitivity of the nerve endings in the oropharyngeal mucosa, relieving pain, irritation, or discomfort in that area. 
• Lack of Vasoconstrictive Activity: Unlike other local anesthetics, benzocaine does not possess vasoconstrictive properties. It does not cause constriction of blood vessels in the oropharyngeal area, which can be advantageous in certain situations, such as when treating inflamed tissues. 
• Lack of Systemic Effects: benzocaine oropharyngeal preparations are primarily designed for local application, and systemic absorption is minimal when used as directed. However, it is essential to note that excessive or prolonged use, application to broken or inflamed tissue, or ingestion of benzocaine can increase the risk of systemic absorption and potential adverse effects, including methemoglobinemia (a condition discussed in previous responses). 

Pharmacokinetics: 

Absorption 

When applied topically to the oropharyngeal mucosa, benzocaine is absorbed locally. The benzocaine formulation’s concentration can influence the absorption rate, the application’s surface area, and intact or inflamed mucosal tissue. Absorption through intact mucous membranes is generally limited, but absorption may be increased if the mucosa is broken or inflamed. 

Distribution 

After absorption, benzocaine remains primarily at the application site within the oropharyngeal region. Due to its local anesthetic nature, it does not distribute extensively throughout the body. Systemic distribution of benzocaine is minimal when used topically as directed.  

Metabolism 

benzocaine is primarily metabolized in the liver through enzymatic processes. It undergoes ester hydrolysis, primarily by the enzyme pseudocholinesterase, to form para-aminobenzoic acid (PABA) and other metabolites. PABA is further metabolized to conjugates and excreted in the urine. The metabolism of benzocaine occurs relatively rapidly. 

Elimination and Excretion 

The metabolites of benzocaine, including PABA and its conjugates, are excreted mainly in the urine. The elimination half-life of benzocaine is relatively short, ranging from about 1 to 2 hours. 

Adminstartion

Administration: 

benzocaine oropharyngeal preparations are typically available as lozenges, sprays, or gels specifically designed for topical application to the oropharyngeal region.  

• Follow Product Instructions: Read and carefully follow the instructions provided by the manufacturer on the product packaging.  
• Clean Hands and Oral Cavity: Before using benzocaine oropharyngeal products, ensure your hands are clean and dry. Rinse your mouth with water if necessary to remove any debris or residue. 
• Lozenges: Place the lozenge in your mouth and allow it to dissolve slowly for benzocaine lozenges. Avoid chewing or swallowing the lozenge whole.  
• Sprays: For benzocaine throat sprays, shake the container well before use. Hold the spray bottle upright and aim it toward the back of your throat. Depress the spray nozzle while inhaling or exhaling to deliver a fine mist of the product to the affected area.  
• Gels: benzocaine oropharyngeal gels are typically applied using a clean finger or a cotton swab. Spread a small amount of gel over the affected mouth or throat area. Gently massage or dab the gel onto the mucous membranes.  
• Avoid Ingestion: It is important to remember that benzocaine oropharyngeal preparations are intended for topical use only and should not be ingested or swallowed.

Patient Information Leaflet

Patient information leaflet 

Generic Name: benzocaine oropharyngeal 

Why do we use benzocaine oropharyngeal? 

benzocaine oropharyngeal preparations are commonly used for their local anesthetic properties to relieve pain and discomfort in the oropharyngeal region temporarily. Here are some common uses of benzocaine oropharyngeal products: 

• Sore Throat: benzocaine oropharyngeal preparations, such as lozenges, sprays, or gels, are often used to alleviate the pain and irritation of a sore throat. They can help numb the throat and provide temporary relief. 
• Mouth and Gum Pain: benzocaine oropharyngeal products can relieve pain and discomfort in the mouth and gums caused by mouth ulcers, canker sores, teething in infants, or gum irritation. 
• Throat Irritation and Hoarseness: benzocaine oropharyngeal preparations may help reduce throat irritation and hoarseness caused by excessive voice use, allergies, or respiratory infections. 
• Post-Procedure Relief: After specific medical procedures involving the oropharyngeal area, such as intubation or endoscopy, benzocaine oropharyngeal products can be used to provide temporary relief from post-procedure discomfort. 
• Local Anesthesia: benzocaine oropharyngeal preparations can be used as a local anesthetic for minor surgical procedures or diagnostic tests involving the oropharyngeal region.