Orlistat decreases the absorption of supplemental beta-carotene and vitamin E. There is some evidence to suggest that some patients may have low vitamin D levels while taking
orlistat, even if they are also taking multivitamins.
It is recommended that multivitamin preparations should be taken at least 2 hours after
orlistat, or at bedtime. The US manufacturers suggest that patients taking
orlistat should be advised to take multivitamins, because of the possibility of
reduced vitamin levels. Note that it has been suggested that monitoring of vitamin D may be required, even if multivitamins are given.