The
carcinoid syndrome, a common feature of small
intestinal carcinoid tumors with liver
metastases, includes
flushing,
diarrhea, bronchoconstriction, and right
heart failure. The etiology of the
carcinoid syndrome is not well understood, but
serotonin seems to be involved in the
diarrhea, whereas
tachykinins may play a role in the flush reaction. In a double blind placebo-controlled study, we studied the effect of
octreotide in 20 patients with midgut
carcinoid tumors and liver
metastases. A sc injection of 50 micrograms
octreotide caused a significant (P less than 0.001) decrease in median plasma
tachykinins and serum
pancreatic polypeptide, GH, and
insulin for up to 4 h. Administration of
octreotide (50 micrograms, twice daily, sc) caused a 26% decrease in urinary 5-hydroxyindoleacetia
acid excretion, but the number of
flushing attacks or bowel movements did not change significantly. A typical flush was provoked by
pentagastrin, and plasma
tachykinin and
serotonin levels were measured. The flush reaction was graded on a 10-point visual analog scale.
Octreotide (50 micrograms, sc) given 45 min before flush stimulation prevented
tachykinin release completely and significantly reduced the median
flushing score from 8.5 to 2. Placebo administered in the same way did not prevent
tachykinin release after
pentagastrin administration. Thus,
octreotide prevents
pentagastrin-induced
flushing and the related hormonal changes in patients with the
carcinoid syndrome.