From the Guidelines
Lidocaine is generally considered safe for injection in postpartum patients when used appropriately, with a recommended dose of 0.5-1% lidocaine solution and a maximum safe dose of 4.5 mg/kg (or 300 mg total) without epinephrine, or 7 mg/kg (or 500 mg total) with epinephrine, as supported by recent studies 1.
Key Considerations
- The use of intravenous lidocaine for postoperative pain and recovery should be ratified and approved by the local hospital and medication governance committee, or equivalent, with a recommended initial dose of no more than 1.5 mg.kg-1, calculated using the patient’s ideal body weight and given as an infusion over 10 min, and a subsequent infusion of no more than 1.5 mg.kg-1.h-1 for no longer than 24 h, subject to review and re-assessment 1.
- Lidocaine should not be used at the same time as, or within the period of action of, other local anaesthetic interventions, particularly local anaesthetic nerve blocks, and patients receiving i.v. lidocaine should ideally be managed in a monitored bedspace in a high dependency unit (level 2 care) with particular vigilance in patients with existing comorbidity 1.
- For postpartum patients who are breastfeeding, lidocaine is considered compatible with breastfeeding as minimal amounts transfer into breast milk, and when administering lidocaine, healthcare providers should be aware of potential side effects including allergic reactions, cardiovascular effects (hypotension, arrhythmias), and central nervous system effects (dizziness, seizures) at higher doses 1.
Important Safety Measures
- It's essential to use the lowest effective dose and to aspirate before injection to avoid intravascular administration, and patients with liver disease may require dose adjustments as lidocaine is metabolized in the liver 1.
- Clinicians should remember the possibility of toxicity even though there may be other explanations for a given clinical presentation, and lipid emulsion 20% should be readily available wherever i.v. lidocaine is used, and staff should know where it is kept 1.
Recommendations for Postpartum Pain Management
- A combination of basic analgesics such as paracetamol; NSAIDs or cyclo-oxygenase-2–selective inhibitors; and i.v. dexamethasone, along with a local/regional analgesic techniques (e.g. intrathecal morphine 50–100 μg or diamorphine 300 μg); local anaesthetic infiltration with or without a field blocks such as ilio-inguinal and iliohypogastric nerves blocks or fascial plane blocks (e.g. TAP, quadratus lumborum or ESP blocks) are recommended for optimal pain management after elective caesarean section performed under neuraxial anaesthesia 1.
From the FDA Drug Label
Local anesthetics rapidly cross the placenta and when used for epidural, paracervical, pudendal or caudal block anesthesia, can cause varying degrees of maternal, fetal and neonatal toxicity Adverse reactions in the parturient, fetus and neonate involve alterations of the central nervous system, peripheral vascular tone and cardiac function. The use of some local anesthetic drug products during labor and delivery may be followed by diminished muscle strength and tone for the first day or two of life
The safety of lidocaine for injection in postpartum women is not directly addressed in the provided drug labels. However, the labels do discuss the use of local anesthetics, including lidocaine, during labor and delivery, and the potential risks and adverse reactions associated with their use.
- Key considerations:
- Local anesthetics can cause maternal, fetal, and neonatal toxicity.
- Adverse reactions can involve the central nervous system, peripheral vascular tone, and cardiac function.
- Diminished muscle strength and tone may occur in newborns for the first day or two of life. Given the potential risks, caution should be exercised when considering the use of lidocaine in postpartum women, especially if they have received local anesthetics during labor and delivery 2 2.
From the Research
Safety of Lidocaine for Injection in Postpartum
- The safety of lidocaine for injection in postpartum women has been investigated in several studies 3, 4, 5.
- A study published in Anesthesia and Analgesia found that intraperitoneal instillation of lidocaine improved postoperative analgesia at cesarean delivery and reduced the number of women requesting systemic opioids in the immediate postpartum period 3.
- Another study published in Best Practice & Research: Clinical Anaesthesiology found that lidocaine has analgesic, antihyperalgesic, and anti-inflammatory properties, making it a useful adjuvant for general anesthesia 4.
- A systematic review and meta-analysis published in the Journal of Gynecology Obstetrics and Human Reproduction compared the efficacy of ropivacaine and lidocaine infiltration for controlling postpartum perineal pain and found no significant difference between the two groups in terms of visual analogue scale pain scores 5.
Potential Risks and Considerations
- A case report published in BMJ Case Reports highlighted the importance of administering lidocaine with care, as even "safe" medications can cause adverse effects in certain patients, such as those with liver disease 6.
- A review article published in Pain Management Nursing emphasized the need for nurses to stay up to date on the use of intravenous lidocaine for postoperative pain management and provided practical tools for developing protocols and educational content 7.
Key Findings
- Lidocaine appears to be safe and effective for use in postpartum women, particularly for pain management after cesarean delivery or perineal repair 3, 4, 5.
- However, it is essential to administer lidocaine with care and consider individual patient factors, such as liver disease, to minimize the risk of adverse effects 6.