Benzocaine is a prescription medication that helps alleviate pain. It is often given as a topical ointment and works by numbing the area. Many over-the-counter medications for toothaches and sore throats use benzocaine as a numbing agent.
Most people who abuse benzocaine may do so because benzocaine treatment may be cheaper and more available than seeking professional medical help. This is unlike other substances, where there is a chemical dependency to the drug that usually causes the person to abuse the substance.
Side effects of long-term use or short- or long-term abuse can include tiredness, convulsions, respiratory problems, numbness, problems maintaining a proper internal body temperature, double vision, and psychological problems such as anxiety. Sometimes abuse can even result in benzocaine toxicity.
Overuse of mouth and throat sprays containing benzocaine can be potentially fatal. This is one of the fastest ways to ingest toxic levels of the drug.
Benzocaine overuse can bring on methemoglobinemia---when an abnormal amount of haemoglobin builds up in blood, sometimes making it harder for oxygen to reach tissues in the body. If there are too many methemoglobins, certain systems---such as respiratory and cardiovascular---may not be able to function properly.
Blood transfusions may be necessary in severe cases of benzocaine toxicity. The most common treatment is and prescription oral medication called methylene blue. Ascorbic acid treatment is a less common treatment which may be used to reduce the level of haemoglobin in the body.