Zollinger-Ellison syndrome

The incidence of pituitary tumors is increased in multiple endocrine adenomatosis or neoplasia (MEA or MEN) (especially type I: autosomal dominant inheritance with high penetrance, also involves pancreatic islet cell tumors (which may produce gastrin and hence Zollinger-Ellison syndrome) and parathyroids (hyperparathyroidism), and in which the pituitary tumors are usually nonsecretory).

Omeprazole for Zollinger-Ellison syndrome: 20mg PO q d to 120mg PO TID (dose adjusted to keep basal acid output < 60 mEq/hr). Side effects: N/V, H/A, diarrhea, abdominal pain or rash in 1–5% of patients. Supplied: 10, 20 & 40mg delayed-release capsules. Available OTC in 20.6mg tablets as Prilosec OTC.

Zollinger-Ellison syndrome, can inhibit attachment of intrinsic factor to ileal receptors and so vitamin B12 deficiency.