To : Anna Hayward Re : Marijuana It is true that in heavy smokers (multiple joints daily) that THC will leak from their adipose tissue for weeks (maybe up to 4). However, in the ocassional user, it would be much less. The mean terminal half-life is 25- 57 hours in non-users. Marijuana tends to be sequestered in peripheral compartments with a hugh volume of distribution of 10 L/kg, which is absolutely enormous. THC does enter milk rather easily, but due to low concentration in the plasma, the absolute dose to the infant is extremely low. Further, while the absolute oral absorption is complete, a little discussed secret is that THC is actually largely sequestered in the liver, so little actually reaches the plasma compartment (which is why people smoke it rather than ingest it orally). So the milk:plasma ratio of about 8 does not equate to a large "clinical" dose of the drug at all. So, lets be clear. If the mom smokes marijuana ocassionally, she should expect that only small levels will be transferred to the infant, probably subclinical, which is why the studies show no developmental abnormalities. However, it should also be clear, that the infant will probably receive enough drug to be 'drug screen positive' for some time. We don't actually know if this would be 3 days, a week, or a month, it would totally depend on the mothers' dose of marijuana. So, while none of us should support marijuana (or alcohol ) use in breastfeeding mothers, we should not get overly strident when it does occur in our clients. Finally, just for your own information, I will be giving a 1.5 hour lecture on Drugs of Abuse in Breastfeeding Mothers at ILCA this year. We'll go over all of the typical drugs, and their breastfeeding kinetics...so join me. Regards Tom Hale, Ph.D. *********************************************** The LACTNET mailing list is powered by L-Soft's renowned LISTSERV(R) list management software together with L-Soft's LSMTP(TM) mailer for lightning fast mail delivery. For more information, go to: http://www.lsoft.com/LISTSERV-powered.html