How do numbing cream and local anesthetic injections differ?
Both use local anesthetics to reduce pain in a treated area while you stay awake. Cream works through the skin; an injection delivers the medicine into tissue or near a nerve. Neither guarantees a completely painless procedure. Tell the clinician if you feel pain, even if pressure or movement is expected.
- Topical anesthetic: a cream, gel or other surface preparation used for suitable skin procedures. Examples include lidocaine and combinations of lidocaine with prilocaine. Surface numbing may not be enough for deeper treatment.
- Local anesthetic injection: numbs the area being treated. The injection itself can briefly sting. Some formulations include adrenaline, also called epinephrine, which can prolong the effect.
- Nerve block: an injection near a nerve to numb the area it supplies. This is a technique using local anesthetic, rather than a separate drug type. Regional anesthesia numbs a larger part of the body.
Sedation changes how relaxed, drowsy or aware you are; general anesthesia makes you unconscious. These need a different care and monitoring plan from skin numbing. Ask which approach is proposed rather than assuming every clinic offers each option.
The choice depends on the procedure, treatment site, product and your health. Numbing does not prevent the procedure’s other complications. If you are considering filler, read about HA filler benefits and risks as well.
How long does it take to work, and how long does it last?
There is no single timing for all anesthetics. The wait before treatment and the time until feeling returns are different. Both depend on the medicine, formulation, area and how it is used.
Cream needs time to act through the skin; injections often work sooner. Ask how much time to allow at your appointment and when numbness should wear off. A stronger cream or longer application is not automatically better or safer.
What should you tell the clinician beforehand?
- Any previous reaction to numbing medicine, including at the dentist. Describe what happened, such as a rash, swelling, racing heartbeat or fainting.
- Your medical conditions, especially heart, liver or lung disease, G6PD deficiency or a history of problems with the blood carrying oxygen.
- Medicines, supplements and any other numbing products you use. Do not stop prescribed medicines on your own.
- Pregnancy or breastfeeding, and any rash, broken skin or infection in the treatment area.
If needles make you anxious or faint, say so before treatment. Follow the specific preparation instructions for your procedure; skin numbing and sedation do not have the same requirements.
Can you apply numbing cream at home before treatment?
Do not buy a high-strength cream or apply extra numbing medicine to prepare for a cosmetic procedure yourself. If your clinician asks you to use a product beforehand, follow the instructions for that exact product and area.
Too much medicine can enter the bloodstream when creams are used over large areas, on damaged skin or for too long. Covering the skin can also increase absorption. Only cover the area if your clinician has specifically directed it for that product. Do not try to speed up absorption yourself. Keep numbing products away from the eyes unless a clinician is using a product specifically intended for that purpose.
What side effects need attention?
Temporary stinging, redness, itching or swelling can occur; injections may also leave bruising. A racing heartbeat or fainting does not always mean an allergy. Anxiety or adrenaline in some injections can cause similar symptoms, so tell the clinician and let them assess the reaction.
Too much local anesthetic in the bloodstream can affect the brain and heart. Report a metallic taste, ringing ears, marked dizziness, confusion or slurred speech immediately.
Some local anesthetics, including prilocaine-containing products, can reduce the blood’s ability to carry oxygen, a condition called methemoglobinemia. Unusual pale, gray or blue skin, especially with breathlessness, needs urgent medical attention.
Get emergency medical help for difficulty breathing, swelling of the face, tongue or throat, seizures, collapse or a severe irregular heartbeat. Do not wait for a routine clinic reply or try to treat a serious reaction at home.
What should you do while the area is still numb?
Avoid rubbing, scratching, biting or exposing numb skin to very hot or cold temperatures: you may not feel an injury. Follow the aftercare for the actual procedure, including any instructions about compresses.
Contact the treating clinic if numbness lasts longer than expected or pain, redness or swelling is increasing. The urgent symptoms above need immediate medical care.
What should you check at a clinic in Thailand?
Ask for the exact medicine name, strength, formulation and Thai registration details. A cream and an injectable product are not interchangeable. An overseas approval or a product photograph does not confirm Thai registration, suitability for you or what will be used at your appointment.
Before treatment at Smooth Clinic, discuss your concerns about pain, the proposed numbing method and how to get help afterwards. Ask for an explanation you understand before agreeing to the procedure.
References
- NHS. Local anaesthetic and general anaesthetic. Patient information on the different approaches.
- District of Columbia Society of Anesthesiologists. Types of anesthesia. Local, regional, general anesthesia and sedation.
- DailyMed. Lidocaine and prilocaine cream, 2.5%/2.5%. U.S. prescribing information; formulation-specific precautions, interactions and methemoglobinemia warnings.
- DailyMed. Lidocaine hydrochloride injection. U.S. prescribing information; local and regional anesthesia precautions.
- U.S. FDA. Warning about certain topical pain-relief products used for cosmetic procedures, 2024. This U.S. warning does not establish Thai registration status.
- NHS Specialist Pharmacy Service. Managing reactions to dental local anesthetic injections, 2024. Used for the distinction between allergy, anxiety and adrenaline-related reactions; dental treatment details are not a cosmetic-treatment protocol.