Page 440 Acute Pain Management

feeding) and maternal symptoms, codeine dose, and in some cases CYP2D6 phenotype, has
been identified (Madadi et al, 2009 Level III‐3).
As oxycodone is concentrated in human breast milk, and breastfed infants may receive >10%
of a therapeutic dose, safety with repeated maternal dosing has been questioned (Ito, 2000).
As a component of multimodal analgesia in the first 72 hours after Caesarean section, there
may be minimal risk to breastfeeding infants as only a low volume of milk is ingested during
this period (Seaton et al, 2007 Level III‐3).
Use of tramadol (100 mg 6 hrly) on days 2 to 4 after Caesarean section was associated with
a milk‐to‐plasma ratio of 2.2, a relative infant dose of 2.9%, and no detectable behavioural
effects in the infants (Ilett et al, 2008 Level III‐2). However, as with other drugs, these data
cannot be directly extrapolated to long‐term use at later postpartum stages when the volume
of ingested milk is higher.
Methadone is considered compatible with breastfeeding. Plasma levels of methadone were
low in infants of breastfeeding mothers on methadone maintenance programs, and no effect
on infant neurobehavioural outcomes were found on days 3, 14 and 30 following birth (Jansson
et al, 2008 Level III‐3).
Other medications related to pain relief
After epidural administration, local anaesthetics showed acceptable milk‐to‐plasma ratios of
1.1 for lignocaine (lidocaine) and 0.34 for bupivacaine (Ortega et al, 1999) and 0.25 for
ropivacaine (Matsota et al, 2009), which are considered safe (Rathmell et al, 1997). Use of epidural
analgesia (local anaesthetic ± fentanyl) during labour (Chang & Heaman, 2005 Level III‐3) or as
PCEA after Caesarean section (Matsota et al, 2009 Level IV) did not influence neurobehavioural
scores in healthy term infants.
There is very little information about antiemetic use, and in almost all cases the manufacturers
do not recommend their use during lactation (for recommendations see Table 11.3). Animal
studies suggest possible CNS effects in the newborn, but human anecdotal experience is
favourable.
In a single case report, the milk‐to‐plasma concentration of gabapentin was 0.86, the relative
infant dose was 2.4%, and no adverse effects were noted in the infant. While suggestive of
safety during lactation, a careful individual risk‐benefit analysis was suggested (Kristensen et al,
2006 Level IV).
Table 11.3 The breastfeeding patient and drugs used in pain management
CHAPTER 11 Opioids Safe to use occasional doses. Use repeated doses
Drug
Comments
buprenorphine, codeine, dextropropoxyphene,
with caution, especially if infant is premature or
fentanyl, hydromorphone, methadone,
<4 weeks old; monitor infant for sedation and
morphine, oxycodone, pentazocine, tramadol
Paracetamol other adverse effects
Safe to use
Aspirin Avoid due to theoretical risk of Reye's syndrome;
ibuprofen is preferred
Other NSAIDs
NsNSAIDs, Safe to use
Coxibs Limited data; appear safe
Ketamine Limited data, avoid use

392 Acute Pain Management: Scientific Evidence