The local anaesthetic known as benzocaine is a common ingredient in a number of sore throat treatments, including Ultra Chloraseptic’s menthol flavoured throat spray. In our throat sprays, benzocaine is used to temporarily numb the area affected by throat pain, providing short term relief from symptoms to help you concentrate on the things that matter. Benzocaine is also used in other topical pain relief products such as mouth gels, creams or ointments.^[1]

Below, we explore how safe benzocaine is for use by the general public, including whether children should be allowed to use benzocaine products unsupervised.

How much benzocaine is dangerous?

As with any medicine, it’s important not to take too much benzocaine within a short period of time. In the case of throat sprays, taking too much could risk numbing larger areas than intended as well as the possibility of adverse effects. 

Benzocaine has been linked to a condition called methaemoglobinaemia, which affects the transportation of oxygen through the bloodstream. This condition is associated with some or all of the following symptoms appearing within minutes up to two hours after using benzocaine, as well as some other medications:^[2]

• Pale, blue or grey-coloured lips, nail beds or skin
• Shortness of breath
• Confusion or lightheadedness
• Headache
• Fatigue
• A fast heart rate. 

It’s possible to experience this even if you’ve used benzocaine products before, so if you experience any of these symptoms, you should seek medical advice and stop using your throat spray immediately. If you have been told you have methaemoglobinaemia, you shouldn’t use benzocaine throat sprays at all.^[2]

However, by using throat sprays according to the instructions given on the packaging, the risk of developing adverse side effects is lessened. This means taking the recommended dosages at the recommended intervals. For this reason, it’s vital to read all the instructions before you take a medication, so you know what you’re doing and what to expect. You can also use home remedies to help alleviate sore throat pain while you recover from your infection, or seek medical advice if your condition is lasting longer than expected.

Another important part of the instructions on benzocaine and other local anaesthetic products is the recommended age range. The Ultra Chloraseptic children’s blackcurrant flavoured throat spray contains benzocaine to numb the throat and shouldn’t be given to children under the age of six. Any child using the spray should be supervised while doing so to ensure they use the right dosage and don’t exceed the recommended usage period of three consecutive days.

Can you be allergic to benzocaine?

It is possible to be allergic to benzocaine, but this isn’t believed to be common in the UK.^[1,3] The majority of people can use benzocaine and other local anaesthetics in appropriate doses without an allergic reaction – although there may be some minor side effects such as tingling sensations as the anaesthetic wears off and pain from an injection if the anaesthetic was administered in that way.^[1] 

Although the allergy isn’t common, it’s still important to be aware of any adverse effects you experience when taking medications. If you experience allergy-like symptoms after taking benzocaine, it’s worth getting medical advice in case you are allergic to the local anaesthetic or another ingredient within the product you’re using in order to reduce the risk of further allergic reactions. Potential allergy symptoms include:^[4]

• Shortness of breath
• Rashes or itchy skin
• Nausea or vomiting
• Swelling where the anaesthetic was applied
• Diarrhoea
• Sudden disorientation, fatigue or dizziness
• Loss of consciousness
• Anaphylaxis
• Pale or blue colour in the lips, skin, tongue or nail beds.

Local anaesthetics such as benzocaine are generally considered to be safe to use at home. If you experience any undesirable side effects, you should speak to a doctor or pharmacist about what could be causing your symptoms and how they can be treated.^[1]

Resources:

[1] https://www.nhs.uk/conditions/local-anaesthesia/ 

[2] https://www.fda.gov/drugs/drug-safety-and-availability/risk-serious-and-potentially-fatal-blood-disorder-prompts-fda-action-oral-over-counter-benzocaine 

[3] Sidhu, S K et al. “A 10-year retrospective study on benzocaine allergy in the United Kingdom.” American journal of contact dermatitis : official journal of the American Contact Dermatitis Society vol. 10,2 (1999): 57-61. doi:10.1016/s1046-199x(99)90000-3 Available at:  https://pubmed.ncbi.nlm.nih.gov/10357712/ 

[4] https://www.nhs.uk/conditions/allergies/