Benzocaine

Benzocaine is an ester-type local anesthetic that reversibly blocks voltage-gated sodium channels in nerve endings. This prevents the initiation and conduction of nerve impulses, creating temporary numbness and relieving mild to moderate pain and itching.

Benzocaine is generally safe for adults and children 2 years of age and older, but is not recommended for children under 2 years. It is well-tolerated, but rare cases of methemoglobinemia, a serious blood disorder, have been reported.

• Canker sores
• Toothache and gum irritation
• Denture or orthodontic appliance irritation
• Sore throat
• Sunburn, minor burns, and cuts
• Insect bites and stings
• Hemorrhoids
• Minor skin irritations and itching
• Ear pain (otitis)
• Premature ejaculation

Benzocaine is an ester-type local anesthetic that reversibly blocks voltage-gated sodium channels in peripheral neurons. Benzocaine diffuses across the neuronal plasma membrane in its uncharged base form and is protonated in the cytoplasm to block the sodium channel pore. This prevents depolarization of the neuronal membrane and the initiation and conduction of nerve impulses. It reduces the generation and transmission of sensory nerve impulses near the site of application. Benzocaine has a quick onset and the shortest duration of action among commonly used topical anesthetics.

When used as directed, some benzocaine may be absorbed through the skin and mucous membranes and hydrolyzed by esterases in plasma and the liver, but this is negligible.

Benzocaine reversibly blocks voltage-gated sodium channels in peripheral nerves, preventing the initiation and conduction of nerve impulses. This reduces sodium ion permeability of the neuronal membrane and inhibits depolarization. The result is temporary numbness at the application site and relief from pain, itching, and irritation.

Adults and children 2 years and older:

• Mouth and gum irritation: Apply 10-20% solution or gel to affected area as needed. Maximum 4 times daily.
• Sore throat/mouth pain: Dissolve 1 lozenge slowly in mouth; repeat every 2 hours as needed (generally use <2 days). OR apply 1 spray to affected area, spit after 1 minute; may repeat up to 4 times.
• Hemorrhoids: Apply 5-20% solution or ointment to affected area up to 4 times daily.
• Bee stings, burns, insect bites: Apply 5-20% solution to affected area every 6-8 hours.
• Dental pain: Apply 2.5-20% solution as needed.

Children (4 years and older): For teething pain, apply 7.5-10% gel to affected gum area; not to exceed every 6 hours.

Important: Do not use in children under 2 years. Do not exceed recommended dosage.

For external use only. Apply a small amount to clean, dry affected area. Avoid contact with eyes. Wash hands after application. Do not use for more than 7 days.

For oral use: Apply gel/liquid to affected area and leave in place for at least 1 minute, then spit out. Dissolve lozenges slowly in the mouth; do not chew.

For ear use: 4-5 drops of 20% suspension for adults.

If you miss a dose, apply it as soon as you remember. If it is almost time for your next dose, skip the missed dose. Do not double the dose.

• Burning or stinging at application site
• Contact dermatitis
• Pruritus (itching)
• Erythema (redness)
• Rash
• Urticaria (hives)
• Edema
• Methemoglobinemia (serious, rare) - pale/gray/blue skin, headache, rapid heart rate, shortness of breath, dizziness, fatigue

Note: Allergic reactions may occur.

• Do not use in children under 2 years
• If symptoms do not improve in 7 days, or if irritation, pain, or redness persists or worsens, consult a dentist or doctor
• If sore throat is severe, persists for more than 2 days, or is accompanied by fever, headache, rash, swelling, nausea, or vomiting, consult a doctor
• Caution in patients with G6PD deficiency, pyruvate kinase deficiency, hemoglobin-M disease, or NADH-methemoglobin reductase deficiency
• Caution in patients with asthma, bronchitis, emphysema, heart disease, or anemia
• Do not use on open wounds, for prolonged periods, or on large areas of the body

• Allergy to benzocaine or other 'caine' anesthetics
• Children under 2 years
• Consult doctor before use during pregnancy

• Drugs that cause methemoglobinemia (e.g., dapsone, articaine, phenazopyridine): Increased risk of methemoglobinemia
• Sulfonamides (e.g., sulfacetamide, sulfamethoxazole): Potential interaction
• Hyaluronidase: May need to avoid in some cases
• St. John's Wort: Potential interaction

Although certain medicines should not be used together, in some cases they may be used together under doctor supervision.

No significant food interactions are known. Interactions with alcohol or tobacco may occur.

[CONSULT YOUR DOCTOR] There is insufficient data on the safety of benzocaine during pregnancy. When used as directed, very little is absorbed and is unlikely to reach the developing fetus. Two studies did not find an increased risk of birth defects with first-trimester use. Consult your doctor before use during pregnancy.

[CONSULT YOUR DOCTOR] Benzocaine has not been well studied for use during breastfeeding. It is not recommended to apply to the breasts or nipples due to the risk of methemoglobinemia if ingested by the baby. If applied elsewhere and the baby does not get it in their mouth, it is unlikely to affect a breastfed infant. Wash hands well after use.

Do not use in children under 2 years. Children 2 years and older should be supervised during use. Safety and efficacy of lozenges/sprays for sore throat in children under 5 years have not been established.

There is no information on the relationship of age to the effects of benzocaine in geriatric patients. However, general usage guidelines apply.

Systemic absorption with topical application is minimal, so no dosage adjustment is needed for renal or hepatic impairment.

Overdose increases the risk of methemoglobinemia. If more than used for pain is accidentally swallowed, seek medical help immediately.

Store at 20-25°C (68-77°F). Keep out of reach of children.

Benzocaine (C₉H₁₁NO₂), molecular weight 165.189 g/mol.