What muscle relaxant is safe for a lactating woman to use?

Safe Muscle Relaxants in Lactation

All neuromuscular blocking agents (suxamethonium, rocuronium, vecuronium, atracurium) are completely safe during breastfeeding with no interruption of nursing required, and breastfeeding may resume immediately after the mother recovers from anesthesia. 1

Neuromuscular Blockers (Safest Option)

• Neuromuscular blocking agents have poor oral bioavailability and pose no risk to breastfed infants even when used during operative procedures. 1
• Safe agents include:
  • Suxamethonium 1
  • Rocuronium 1
  • Vecuronium 1
  • Atracurium 1
• Reversal agents (neostigmine and sugammadex) are also compatible with breastfeeding 1
• No waiting period is required before resuming breastfeeding—nursing may begin as soon as the mother has recovered sufficiently from anesthesia 1, 2

Alternative First-Line Approach for Musculoskeletal Pain

If the question pertains to oral muscle relaxants for musculoskeletal pain (rather than surgical neuromuscular blockade), the evidence strongly supports a different approach:

• Multimodal analgesia with non-opioid drugs should be the first-line approach for musculoskeletal pain in lactating mothers 1
• Paracetamol and ibuprofen are the safest options, compatible with immediate breastfeeding without any waiting period 1, 3, 2
• Ibuprofen is the preferred NSAID with the most reassuring safety data and extensive use for postpartum pain 2
• Other safe NSAIDs include diclofenac (second safest after ibuprofen), naproxen, celecoxib, ketorolac, and parecoxib 1, 3, 2

Critical Safety Considerations for Any Sedating Medication

• Mothers taking any sedating muscle relaxant must never co-sleep with their infant, as natural maternal responsiveness may be inhibited 1, 3
• Extra caution is required for infants less than 6 weeks of age due to immature hepatic and renal function 1, 2
• Preterm infants have the highest medication sensitivity and require heightened vigilance 1, 2
• Monitor infants for unusual drowsiness, poor feeding, or decreased responsiveness when mothers use any sedating medication 1, 3

If Opioid Analgesia Is Required

• Morphine is the preferred opioid choice at the lowest effective dose for the shortest duration if severe pain requires strong analgesia 1, 3, 2
• Infants should be monitored for excess sedation, respiratory depression, drowsiness, and poor feeding when mothers use morphine 2

Common Pitfall to Avoid

• Do not unnecessarily interrupt breastfeeding or advise expressing and discarding milk when using paracetamol or NSAIDs—this is completely unnecessary 2