To      : Catherine Mallon
Re      : Cocaine use and Breastfeeding


The question "Should a drug abuser breastfeed" always seems to get me into
trouble with some of my colleagues.  I'll let each of you answer this for
yourself, but I will answer the kinetics part of this question,  as I seem to
get this question every week.

It is true that cocaine has a very brief half-life (0.8 to 1.3 hr) in the
plasma compartment, after which it is rapidly metabolized to benzoecgonine
(about 50%) which is inactive. Plasma Cocaine may be detectible for up to 4-6
hours at rather "minimal" levels, as it is slowly released from peripheral
binding sites.

The benzoecgonine metabolite (inactive) has a much longer half-life, about 5-7
hours in adults.  Interestingly, it is the metabolite that the urine screens
detect,  as cocaine itself is only detectible in urine for up to 8 hours,  but
benzoecgonine is detectible( in adults ) for up to 144 hours, and maybe many
times this in neonates (weeks).

So if you're asked this question, "When can I breastfeed",  I generally answer
"after 24 hours". This also allows for elimination of any other medication she
may have coingested.

But I also inform the mother that her infant may be "Drug Screen Positive" for
cocaine for weeks as benzoecgonine probably transfers into milk in small levels
for long periods (perhaps >144 hrs), and that this may have legal complications
if her infant 'tests positive'.  This is certainly so for other medications
such as marijuana, PCP, etc,  which can transfer via milk to the infant in high
enough concentrations that the infant's urine is drug screen positive for long
periods.  Although the metabolite (benzoecgonine) may not be active,  the
police don't seem to discriminate this factor.

Regards

Tom Hale