Indications
Prilocaine is a local anaesthetic that numbs a small area of the body. It is most often found in a cream combined with Lidocaine, applied to the skin before needle procedures (such as drawing blood or putting in a drip), minor skin surgery, laser treatments, or cleaning of leg ulcers. Some creams and sprays with Lidocaine are also used to delay premature ejaculation. As an injection, Prilocaine is used by dentists and doctors for dental work and nerve blocks.
How It Works
Prilocaine blocks sodium channels in nerve fibres. This stops nerves from sending pain signals to the brain, so the area becomes numb for a time. Feeling returns as the medicine is carried away by the blood.
Dosage and Administration
Cream: use exactly as directed on the label or by your doctor. Typically a thick layer is applied to intact skin and covered with a dressing for about 1 hour (up to 5 hours) before the procedure, then wiped off. The amount and area depend on age and weight, and the maximum area is smaller for children. For the premature ejaculation spray or cream, use the number of sprays or amount stated on the label a short time before intercourse, and wipe off any excess. Injections are given only by a dentist, doctor or nurse, who chooses the dose.
Interactions
- Medicines that can cause methaemoglobinaemia (a blood problem where less oxygen is carried), such as Sulfonamides, Dapsone, Nitrates, Nitrofurantoin, Phenytoin and Primaquine: higher risk.
- Other local anaesthetics: effects add up.
- Heart rhythm medicines such as Amiodarone: use with care.
Contraindications
- Allergy to Prilocaine, Lidocaine or other amide-type local anaesthetics.
- Congenital or inherited methaemoglobinaemia.
- Cream should not be used on broken skin, wounds, the eyes or the middle ear, or in premature babies.
Side Effects
The cream may cause temporary paleness, redness, swelling, itching or a burning feeling where it is applied. Sprays used before sex may cause numbness or irritation for the partner if not wiped off; they can damage some condoms, so check the label. Injections may cause numbness lasting a few hours, and rarely dizziness or a metallic taste.
Get urgent medical help if you notice bluish or grey lips, skin or nails, breathlessness, unusual tiredness or headache (signs of methaemoglobinaemia), or swelling of the face or throat, seizures, confusion, ringing in the ears, or a slow or irregular heartbeat.
Pregnancy and Lactation
Small amounts used on the skin or by a dentist are generally considered acceptable in pregnancy and breastfeeding when needed. Ask your doctor before use. Prilocaine should not be used for blocks during labour without specialist advice because of the risk of methaemoglobinaemia in the newborn.
Precautions and Warnings
Babies under 3 months and people with G6PD deficiency are more likely to develop methaemoglobinaemia. Do not use more cream or a larger area than advised, and do not leave it on longer than directed. Keep it away from the eyes. Numb skin can be injured without you feeling it, so avoid scratching, heat or cold on the area until feeling returns. After dental injections, avoid hot drinks and chewing until numbness wears off.
Overdose
Too much may cause numbness of the mouth, dizziness, ringing in the ears, blurred vision, bluish skin, seizures and heart problems. Remove any cream and seek emergency medical help.
Therapeutic Class
Local anaesthetic (amide type).
Storage
Store below 30°C in a dry place, away from light and out of the reach of children. Do not freeze. Dental cartridges and injections: as directed on the pack.
Prepared by the Oshud Alo team from standard drug references. For information only; always follow your doctor's advice.