Indications
Lidocaine (also called lignocaine) is a local anaesthetic that numbs a part of the body. It is used:
- As an injection, often with Adrenaline, to numb the area for dental work, stitching, minor surgery and other procedures.
- As a gel, cream, ointment or spray to numb the skin or the lining of the mouth, throat, urinary passage or back passage before procedures, and to ease pain from piles, mouth ulcers or minor skin conditions. A cream with Tetracaine is used to numb skin before procedures.
- In combination ear drops, haemorrhoid creams and eye drops to reduce pain alongside other ingredients.
- In hospital, by injection into a vein, to treat certain serious heart rhythm problems.
How It Works
Lidocaine blocks sodium channels in nerve cells, so pain signals cannot travel from the area to the brain. The area goes numb for a while and feeling returns as the medicine wears off. In the heart, the same action calms some abnormal heart rhythms.
Dosage and Administration
- Injections are given only by a doctor or dentist, who decides the dose based on the procedure and body weight.
- Gels, creams, ointments and sprays: apply a thin layer to the area as directed on the label or by your doctor. Do not use more than the recommended amount, on large areas, on broken or raw skin, or under a tight covering unless advised.
- Children: only as prescribed. Do not use lidocaine gels for teething pain in babies unless a doctor advises it.
Wash hands after applying, and keep it away from the eyes unless it is an eye product.
Interactions
Amiodarone, other heart rhythm medicines, beta blockers such as Propranolol, and Cimetidine can raise Lidocaine levels when it is used in large amounts or by injection. Using other local anaesthetics at the same time adds to the effect. Tell your doctor or dentist about all medicines you take.
Contraindications
- Allergy to lidocaine or other amide-type local anaesthetics (such as Bupivacaine or Prilocaine), or to any ingredient of the product.
- Injection into a vein: certain types of heart block or very slow heart rate, unless the doctor decides otherwise.
- Ear products: a perforated (torn) eardrum, unless a doctor advises.
Side Effects
Local: redness, burning, stinging, swelling or itching where it is applied, and temporary numbness. If too much reaches the bloodstream, it can cause dizziness, light-headedness, numbness around the mouth, a metallic taste, ringing in the ears, blurred vision, drowsiness, confusion, shaking and, rarely, fits or a slow heartbeat.
Get urgent medical help if you have a fit, confusion, a very slow or irregular heartbeat, fainting, difficulty breathing, or signs of a serious allergic reaction (swelling of the face, lips or throat, widespread rash). In a child, get help straight away if lidocaine is swallowed or a large amount is applied.
Pregnancy and Lactation
Local use is generally considered acceptable during pregnancy and breastfeeding when a doctor or dentist advises it. Only small amounts pass into breast milk.
Precautions and Warnings
After it is used in the mouth or throat, do not eat, drink or chew gum for about 1 hour, as you may choke or bite your tongue or cheek; avoid hot drinks until feeling returns. Protect numb areas from injury, heat and cold. Use with care in people with heart, liver or kidney problems, epilepsy, or in older or very ill people. Keep out of the reach of children, as swallowing it can be dangerous.
Overdose
Too much can cause numbness around the mouth, dizziness, confusion, fits, a slow heartbeat and breathing problems. This is an emergency; seek medical help straight away.
Therapeutic Class
Local anaesthetic (amide type); also a class Ib antiarrhythmic.
Storage
Store below 30°C in a dry place, away from light and out of the reach of children. Do not freeze. Keep sprays away from heat and flames.
Prepared by the Oshud Alo team from standard drug references. For information only; always follow your doctor's advice.