A 63 year old male presented with chronic watery diarrhea associated with flushing charecterised by sudden onset deep red or violaceous erythema of the upper body often with pruritus, lacrimation and facial edema. The flushing was noticed to be precipitated by exercise, alcohol, stress and cheese intake. He has a history of wheezing and clinical examination revealed pellagra like skin lesion. All are useful steps in the treatment of this clinical condition, EXCEPT: