Slippery Elm and its Effect on Anti-convulsant Drugs

I work as a support worker with people who have disabilities. One young lady I support has been prescribed slippery elm by her naturopath. Her general practitioner will not write this medication onto her medical therapy sheet as he does not know how it will work with all her other traditional medications. She is on epilim, Neulactil, Tegretol & artane. I am hoping you may shed some light on this.

Slippery elm bark powder is regarded as safe to take with medications and not known to cause side effects. Its soothing effect is due to the abundance of mucilage. It does contain tannins, which can inhibit absorption of food and drugs. It is advisable to take it at other times that taking food or drugs.
If the general practitioner wants to see the chemicals in slippery elm bark powder, he can refer to James Duke's USDA plant database www.ars-grin.gov/duke/. The page sun.ars-grin.gov:8080/npgspub/xsql/duke/plantdisp.xsql?taxon=1032 lists the chemicals along with their concentrations in each plant part.