The U.S. Food & Drug Administration as well as other medical/research organizations have reported that in infants ages of approximately 4 weeks to 5 months show 2-fold higher mean peak plasma concentrations after the 10th dose of metoclopramide. Although this is in infants there is insufficient research to demonstrate whether cumulative dose generated anxiety in adults is due to similar biological effects. Metoclopramide does bind to plasma albumin at a rate of 13 % to 30 %. This of course is a possible mechanism giving some explanation as to why extrapyramidal symptoms occur after accumulated or total dosage. As with many issues related to medications, insufficient research to determine causes of extrapyramidal effects is rarely conducted due to cessation of the medication leading to cessation of the symptoms. It should also be noted that infants may carry a fetal protein named alpha-fetoglobulin that is a known binder of many medications.
Elimination or clearing of metoclopramide must occur for anxiety induced by metoclopramide to cease. The medication is minimally metabolized; it is not known whether the metabolite that is present in urine is active. 90 % of the medication clears through urine and feces, meaning its presence is persistent for a period of time. Hemodialysis will not remove metoclopramide likely due to its binding to albumin.
If you have suffered with anxiety due to metoclopramide usage as I have, thus causing me to post two articles on metoclopramide, unfortunately the related anxiety may require days to cease. I have yet to arrive at that time although I have improved dramatically with low doses of Xanax and Benadryl.