-  Withdraw antagonist medications : Labetalol, Bisoprolol, Reserpine, Amitriptyline + derivatives, Imipramine + derivatives, Doxepin, Amoxapine, Loxapine, Maprotiline, Trazodone, Phenylephrine, Phenylpropanolamine, Pseudoephedrine, Ephedrine, Cocaine, Bethanidine, Debrisoquine, Bretylium, Guanethidine, Phenothiazines, Thioxanthenes, Butyrophenones, Amphetamine + related compounds, Tyramine, Beta-sympathomimetics, Dobutamine, Dopamine, Metaraminol, Doxazosin mesilate. See mechanism.

-  Administer lugol’s solution 1 drop 2-3 times a day, 3 days before and 7 days after injecting the MIBG to prevent free iodine uptake by the thyroid gland.

-  If needed, treat hypertension with propranolol, conversion enzyme inhibitors (captopril) or Phenoxibenzamine. If they have no effect, give alternatively calcium channel blockers.

-  Do not affect MIBG uptake: Clonidine, Alphamethylparathyrosine.

-  When injecting the radiotracer, check heart rate and blood pressure every 15 min for 30 min.

References:

1  Diez L, Mitjavila M, Tumores Neuroendocrinos: estudios con meta-yodo-bencil-guanidina, p: 549-561 in: Medicina Nuclear Aplicaciones Clínicas. Eds: I. Carrio - P. González. Editorial Masson, Barcelona España, 2003.

2  Hay RV, Scintigraphic Imaging of the Adrenals and Neuroectodermal Tumors, in Henkin RE et al. Nuclear Medicine. Mosby St Louis 1996, p 855-876.