All the NSAID's are basically the same as far as efficacy and side
effects in the mother.  They are all compatible with breastfeeding.
When you have such a situation, you look in the text book (preferably
Dr. Hale's) and then you compare them.

Here's what you will find:

Naproxen:

Protein binding 99.7%
Oral bioavailability 74-99%
Adult half life 12-15 hours

Ibuprofen:

Protein binding >99%
Oral bioavailability 80%
Adult half life 1.8-2.5 hours

Diclofenac

Protein binding 99.7%
Oral bioavailability complete
Adult half life 1.1 hours

I won't go through them all.  All, given the risks of *not*
breastfeeding; all, given the risks of forcing weaning on an 18 month
old; all, are compatible with breastfeeding.  But probably ibuprofen
would the best choice with less oral bioavailability than diclofenac,
and a much shorter adult half life (and probably pediatric half life
as well) than naproxen.  Better, but not the others are acceptable
too.

Indomethacin is used in small premature babies in quite large doses to
deal with problems in the heart (patent ductus).  Very little gets
into the milk and it is probably safe.  However, if NSAID's are an
option, they are safer for the mother, as this drug does have a fair
number of side effects, potentially serious.  Slow release
preparations are often preferred because blood levels are much lower
in the mother, and thus milk levels are lower.  However, if there is a
problem, they continue to be excreted for longer periods even when the
mother has stopped taking the drug.

I don't know much about methocarbamol, but Hale says minimal amounts
in the milk.  If I remember correctly, it is generally considered
fairly useless for what it is prescribed, but don't quote me on that
last bit, as "I don't know much about methocarbamol" being a
pediatrician.

Jack Newman, MD, FRCPC