From the Guidelines
For perineal repairs after vaginal delivery, 1% lidocaine without epinephrine is the most appropriate choice, with a maximum safe dose of 4.5 mg/kg (not to exceed 300 mg total), as this dosage has been shown to provide effective local anesthesia while minimizing the risk of toxicity 1. When administering lidocaine for perineal repairs, it is essential to consider the patient's weight and calculate the ideal dose based on this, as recommended in the guidelines for intravenous lidocaine use 1.
- Key considerations for lidocaine administration in this context include:
- Using a 25-27 gauge needle to minimize discomfort
- Infiltrating the area requiring repair in a systematic fashion
- Waiting 3-5 minutes before beginning the repair to allow for full anesthetic effect
- Buffering the lidocaine with sodium bicarbonate (9:1 ratio of lidocaine to sodium bicarbonate) to reduce the pain of injection and speed onset of action
- Warming the solution to body temperature to decrease injection discomfort
- Aspirating before injecting to avoid intravascular administration and injecting slowly to minimize pain Given the context of perineal repairs after vaginal delivery, the focus should be on providing effective local anesthesia while ensuring patient safety, and 1% lidocaine without epinephrine, administered carefully and in appropriate doses, is the best choice for this purpose. It's also important to note that while the provided study 1 discusses intravenous lidocaine, the principles of safe dosing and administration can inform the use of lidocaine in other contexts, such as local infiltration for perineal repairs.
From the FDA Drug Label
Adults For normal healthy adults, the individual maximum recommended dose of lidocaine HCl without epinephrine should not exceed 4. 5 mg/kg (2 mg/lb) of body weight, and in general it is recommended that the maximum total dose does not exceed 300 mg.
The maximum recommended dose per 90 minute period of lidocaine hydrochloride for paracervical block in obstetrical patients and non-obstetrical patients is 200 mg total.
The best dose of lidocaine to use for perineal repairs after a vaginal delivery is not explicitly stated in the provided drug label. However, based on the information provided for paracervical block in obstetrical patients, a dose of 200 mg total per 90 minute period may be considered, but this is not directly related to perineal repairs.
- The dose should not exceed 4.5 mg/kg (2 mg/lb) of body weight, and the maximum total dose should not exceed 300 mg.
- It is essential to use the lowest effective concentration and lowest effective dose to guard against systemic toxicity 2.
From the Research
Types of Lidocaine for Perineal Repairs
- Lidocaine-prilocaine cream: This type of lidocaine has been shown to be effective in reducing pain during perineal repair after vaginal delivery 3, 4.
- Lidocaine infiltration: This method involves injecting lidocaine directly into the perineal area and has been compared to lidocaine-prilocaine cream in several studies 3, 4, 5.
- Lidocaine with vasoconstrictors: The use of vasoconstrictors with lidocaine has been shown to be effective in reducing the volume of anaesthetic used during perineal repair 6.
Comparison of Lidocaine Types
- A study comparing lidocaine-prilocaine cream to lidocaine infiltration found that the cream was associated with a shorter duration of repair and higher patient satisfaction 4.
- Another study found that lidocaine-prilocaine cream gave comparable results to lidocaine infiltration in reducing pain during perineal repair 3.
- A study comparing lidocaine to ropivacaine found that both were equivalent in producing post-episiotomy analgesia 5.
- A study comparing lidocaine to bupivacaine found that bupivacaine was associated with prolonged analgesia and fewer doses of oral analgesics 7.
Dosage and Administration
- The dosage and administration of lidocaine can vary depending on the type and method of administration. For example, one study used 1% lidocaine infiltration 5, while another used 0.75% ropivacaine 5.
- The use of lidocaine-prilocaine cream typically involves applying the cream to the perineal area before repair 3, 4.