I wish I could help. The lecithin is to break up the fat so she can pass the ingested fur, but I don't know if clavamox has any kind of "fat"-type ingredient in it (or in the liquid base), so I don't know if it would be an issue or not. I don't think it would affect absorption, I'm just not sure if it would have any impact on the effectiveness of the medication, good or bad.
I'm sorry I'm not more help.