Indications
Benzocaine is a local anaesthetic (numbing medicine) applied to the skin or the lining of the mouth and throat. It is used for temporary relief of pain from mouth ulcers, sore gums, toothache, denture irritation, sore throat (as lozenges or sprays), minor burns, insect bites, itching and haemorrhoids. It is also found in some skin products and hand gels.
How It Works
Benzocaine blocks sodium channels in the nerve endings where it is applied. This stops pain signals from being sent to the brain, so the area becomes numb for a short time, usually 15 to 60 minutes. It does not treat the cause of the pain.
Dosage and Administration
Use as directed on the label. Oral gels (usually 7.5% to 20%): adults apply a small amount to the sore area up to 4 times a day. Lozenges: dissolve slowly in the mouth as directed on the label. Sprays and skin creams: apply a thin layer up to 3 to 4 times a day. Do not use on large areas of broken skin, and do not eat or drink until the numbness wears off, to avoid biting or burning the mouth.
Interactions
- Benzocaine may reduce the effect of sulfonamide antibiotics (e.g. Sulfamethoxazole) applied nearby.
- The risk of methaemoglobinaemia (see Side Effects) may be higher with Dapsone, Nitrates, Nitrofurantoin, Primaquine or other local anaesthetics.
Contraindications
- Allergy to Benzocaine or other ester-type local anaesthetics (e.g. Procaine, Tetracaine).
- Teething pain in babies and children under 2 years.
- Methaemoglobinaemia or a history of it.
Side Effects
Mild stinging, burning, redness or irritation where applied may occur. Some people develop allergic skin reactions. A rare but serious effect is methaemoglobinaemia, in which the blood cannot carry oxygen properly.
Get urgent medical help if you or your child develop pale, grey or blue skin, lips or nails, breathlessness, headache, tiredness, fast heartbeat or confusion after use, or swelling of the face or throat, difficulty breathing or widespread rash.
Pregnancy and Lactation
Occasional short use on a small area is generally considered acceptable in pregnancy and breastfeeding, but ask your doctor or pharmacist first.
Precautions and Warnings
Do not use more often or for longer than the label says, usually not more than 7 days. See a doctor or dentist if pain, sore throat with fever, or mouth sores last longer than 7 days. Do not use for babies’ teething. Keep away from the eyes. People with heart or lung disease, or smokers, may be at greater risk of methaemoglobinaemia.
Overdose
Using too much or swallowing large amounts can cause methaemoglobinaemia, seizures and irregular heartbeat. Seek emergency medical help at once.
Therapeutic Class
Local anaesthetic (ester type).
Storage
Store below 30°C in a dry place, away from light and out of the reach of children. Sprays and sanitiser gels may be flammable; keep away from flames.
Prepared by the Oshud Alo team from standard drug references. For information only; always follow your doctor's advice.