From the Guidelines
To numb skin in preparation for sutures, lidocaine/prilocaine eutectic mixture is the preferred topical anesthetic due to its effectiveness and safety profile, as evidenced by a systematic review of 22 trials encompassing 3000 patients 1. When considering topical anesthetics for skin preparation before suturing, several options are available, including:
- Benzocaine, with an onset of 5 minutes and duration of 15-45 minutes, but with a risk of methemoglobinemia 1
- Lidocaine, with an onset of 2 minutes and duration of 30-45 minutes 1
- Lidocaine/prilocaine eutectic mixture, with an onset of 60 minutes and duration of 60-120 minutes after removal of occlusive dressing, but only for use on intact skin and with a risk of methemoglobinemia 1 However, the lidocaine/prilocaine eutectic mixture is preferred due to its prolonged duration of action and effectiveness in reducing pain sensation, as shown in a prospective study comparing four topical preparations for nonablative laser therapy 1. It is essential to note that caution must be taken when using topical anesthetics, particularly when occlusion is used or large surface areas are treated, due to the risk of adverse events 1. In certain situations, topical agents may offer similar analgesia to infiltrated anesthetics, and studies have found equivalent efficacy in episiotomy repair, split-thickness skin graft harvest, and minor laceration repair 1.
From the FDA Drug Label
Adult Patients-Intact Skin A thick layer of Lidocaine and Prilocaine Cream USP, 2.5%/2.5% is applied to intact skin and covered with an occlusive dressing. Minor Dermal Procedures: For minor procedures such as intravenous cannulation and venipuncture, apply 2.5 grams of Lidocaine and Prilocaine Cream USP, 2.5%/2. 5% (1/2 the 5 g tube) over 20 to 25 cm2 of skin surface for at least 1 hour. Major Dermal Procedures: For more painful dermatological procedures involving a larger skin area such as split thickness skin graft harvesting, apply 2 grams of Lidocaine and Prilocaine Cream USP, 2.5%/2. 5% per 10 cm2 of skin and allow to remain in contact with the skin for at least 2 hours.
To numb the skin in preparation for sutures, Lidocaine and Prilocaine Cream USP, 2.5%/2.5% can be applied. The recommended application time is at least 1 hour for minor procedures and at least 2 hours for more painful procedures. The amount of cream to be applied depends on the size of the skin area, with 2 grams per 10 cm2 of skin for major procedures. It is essential to follow the instructions for application and to use an occlusive dressing to enhance absorption 2.
- Key considerations:
- Apply a thick layer of cream to the skin
- Cover with an occlusive dressing
- Minimum application time of 1 hour for minor procedures and 2 hours for major procedures
- Follow the recommended dosage and application area based on the patient's age and weight 2
From the Research
Topical Anesthetics for Skin Numbing
To numb the skin in preparation for sutures, various topical anesthetics can be used. The choice of anesthetic depends on several factors, including the type of procedure, the location of the procedure, and the patient's medical history.
- Lidocaine: A common topical anesthetic used for skin numbing, lidocaine has been shown to be effective in reducing pain during procedures 3, 4, 5.
- Prilocaine: Another topical anesthetic, prilocaine has been used in combination with lidocaine to enhance its anesthetic effects 4, 5.
- Benzocaine: A topical anesthetic commonly used for minor procedures, benzocaine has been compared to other anesthetics in terms of its efficacy and safety 3, 4, 5.
- Tetracaine: A topical anesthetic with a longer duration of action, tetracaine has been used in combination with other anesthetics to enhance its effects 4.
Allergic Reactions and Cross-Reactions
When using topical anesthetics, it is essential to consider the risk of allergic reactions and cross-reactions.
- Allergic contact dermatitis: A rare condition that can occur with the use of topical anesthetics, allergic contact dermatitis has been reported with the use of prilocaine 6.
- Cross-reactions: Cross-reactions can occur between different topical anesthetics, and it is crucial to test for these reactions before using a new anesthetic 6, 7.
Efficacy of Topical Anesthetics
The efficacy of topical anesthetics can vary depending on the specific anesthetic used and the procedure being performed.