A number of general principles apply when administering analgesic medications for pain management during lactation: (1) the choice of medication should be based on its potential impact on breastfeeding and on the breastfed infant secondary to transfer in human milk; (2) the lowest effective maternal dose is recommended. Breastfeeding is best avoided at times of peak drug concentration in the milk and the infant should be observed of effects of medication transferred in the breast milk. ANZCA, chapter 11.1.3. page 390.

For most medications, information on infant outcome is inadequate or absent. Maternal consent and caution are advisable ANZCA, chapter 11.1.3, p 390.

Condition specific perioperative analgesic issues

Lactating women having procedures with general anaesthetic have been advised to discard their milk for 24 hours following surgery.

After single doses of midazolam (2mg), propofol (2.5 mg/kg) and fentanyl (100 mcg), less than 0.1% of the medications were excreted into milk within 24 hours, suggesting that interruption of nursing may not be required. German p 75; ANZAC chapter 11.1.3. p 390.

Medications that might be prescribed during lactation have been categorized according to their risk for the baby.

Evidence based recommendations specific to the condition

Recommended treatment options

Non-opioids

Paracetamol is considered safe German p 75; ANZCA chapter 11.1.3. p 391.

Non-selective NSAIDs (nsNSAIDs) must be considered individually. Levels in milk are generally low because they are weak acids and extensively plasma bound.

Ibuprofen has the best documentation for safety.Diclofenac and ketorolac are compatible with breastfeeding and with short term or occasional use. ANZCA chapter 11.1.3. page 391 and table 11.1.3. , p 392-394; German p 75.

Opioids

Short term use of opioids is generally considered safe as most opioids are secreted into breast milk in low doses. ANZCA chapter 11.1.3. page 391

Morphine has been recommended the opioid of choice if potent analgesia is required in lactating mothers. ANZCA chapter 11.1.3. page 391

OpioidsBuprenophine, codeine, dextropropoxyphene, fentanyl, hydromorphone, methadone, morphine, oxycodone, pentazocine, tramadol – use of occasional doses is considered safe. Repeated doses should be used with caution, especially if the infant is < 4 weeks old. The infant should be monitored for sedation and side effects. ANZCA Table 11.3., p 392.

Local anaesthetics Bupivacaine, cinchocaine, levobupivacaine, lidocaine, mepivacaine, prilocaine, ropivacaine – unlikely to cause problems. ANZCA Table 11.3. , p 393.

Not recommended

Aspirin– avoid due to the theoretical risk of Reye’s syndrome. ANZCA chapter 11.1.3. page 391; German, p 76.

Ketamine – limited data, avoid use. ANZCA chapter 11.1.3. Table 11.3. p 391.

Pethidine (meperidine) – breastfed infants whose mothers were treated with pethidine were less alert and oriented to auditory cues after Caesarean section compared to mothers who received morphine. ANZCA chapter 11.1.3. page 391.

Regional anaesthesia

After epidural administration, local anaesthetics showed acceptable milk-to-plasma ratios of 1.1 for lidocaine, 0.34 for bupivacaine and 0.25 for ropivacaine. These are considered safe. ANZCA chapter 11.1.3. page 392.

There is very little information about use of anti-emetics and in almost all cases the manufactures do not recommend their use during lactation. ANZCA chapter 11.1.3. page 392.

Summary

In lactating women possible transfer of medications into breast milk and subsequent uptake by the neonate should be considered. Local anaesthetics, paracetamol and several non-selective NSAIDS, in particular ibuprofen, are considered to be safe, as well as morphine and fentanyl.

Supplementary reading

1. Carvalho B, Chu L, Fuller A, Cohen SE, Riley ET. Valdecoxib for postoperative pain management after cesarean delivery: a randomized, double-blind, placebo-controlled study. Anesth Analg. 2006 Sep;103(3):664-70.
2. Leung AY. Postoperative pain management in obstetric anesthesia--new challenges and solutions. J Clin Anesth. 2004 Feb;16(1):57-65.