Dosing & Uses
Dosage Forms & Strengths
IV solution
- 2mCi/mL at calibration time (0.08mg/mL iobenguane sulfate 74 MBq/mL of I 123)
Gamma Scintigraphy
Diagnostic radiopharmaceutical agent for gamma-scintigraphy
Pheochromocytoma or neuroblastoma
- Indicated for detection of primary or metastatic pheochromocytoma or neuroblastoma as an adjunct to other diagnostic tests
- 10 mCi (5 mL; 370 MBq) IV
- Begin whole body planar scintigraphy imaging 24 ± 6 hours following administration
Congestive heart failure
- Indicated for assessment of myocardial sympathetic innervation in patients with NYHA class 2-3 heart failure with an LVEF <35%; among these patients, may help identify those with lower 1 and 2 year mortality risks as indicated by an H/M ratio ≥1.6
- 10 mCi (5 mL; 370 MBq) IV (2 mCi/mL at calibration time)
- Begin anterior planar imaging of the chest at 4 hours (± 10 minutes) following administration
Administration
Administer IV over 1-2 minutes, then flush with 0.9% NaCl to ensure full dose delivery
Radiation safety
- Emits radiation and must be handled with appropriate safety measures to minimize radiation exposure to clinical personnel and patients
- Minimize bladder exposure by encourage hydration before and after to permit frequent voiding, particularly for the first 48 hr after administration
Thyroid blockade
- Administer potassium iodide oral solution or Lugol’s solution (equivalent to 100 mg iodide for adults, body-weight adjusted for children) or potassium perchlorate (400 mg for adults, body-weight adjusted for children) to block uptake of iodine 123 by the patient’s thyroid
- Individualize according to patient; blockade may not be needed for patients who have undergone thyroidectomy or those with limited life expectancy
Dosage Forms & Strengths
IV solution
- 2mCi/mL at calibration time (0.08mg/mL iobenguane sulfate 74 MBq/mL of I 123)
Gamma Scintigraphy
Indicated for detection of primary or metastatic pheochromocytoma or neuroblastoma as an adjunct to other diagnostic tests, and also for assessment of myocardial sympathetic innervation in patients with NYHA class 2-3 heart failure with an LVEF <35%
Pheochromocytoma or neuroblastoma: Begin whole body planar scintigraphy imaging 24 (± 6 hours) following administration
CHF: Begin anterior planar imaging of the chest at 4 hours (± 10 minutes) following administration
Neonates <1 month: Safety and efficacy not established
<16 yr and ≥70 kg: 10 mCi (5 mL; 370 MBq)
<16 yr (3-18 kg)
- 3 kg: 1 mCi (37 MBq)
- 4 kg: 1.4 mCi (52 MBq)
- 6 kg: 1.9 mCi (70 MBq)
- 8 kg: 2.3 mCi (85.1 MBq)
- 10 kg: 2.7 mCi (99.9 MBq)
- 12 kg: 3.2 mCi (118.4 MBq)
- 14 kg: 3.6 mCi (133.2 MBq)
- 16 kg: 4 mCi (148 MBq)
- 18 kg: 4.4 mCi (162.8 MBq)
<16 yr (20-40 kg)
- 20 kg: 4.6 mCi (170.2 MBq)
- 22 kg: 5 mCi (185 MBq)
- 24 kg: 5.3 mCi (196.1 MBq)
- 26 kg: 5.6 mCi (207.2 MBq)
- 28 kg: 5.8 mCi (214.6 MBq)
- 30 kg: 6.2 mCi (229.4 MBq)
- 32 kg: 6.5 mCi (240.5 MBq)
- 34 kg: 6.8 mCi (251.6 MBq)
- 36 kg: 7.1 mCi (262.7 MBq)
- 38 kg: 7.3 mCi (270.1 MBq)
- 40 kg: 7.6 mCi (281.2 MBq)
<16 yr (42-50 kg)
- 42 kg: 7.8 mCi (288.6 MBq)
- 44 kg: 8 mCi (296 MBq)
- 46 kg: 8.2 mCi (303.4 MBq)
- 48 kg: 8.5 mCi (314.5 MBq)
- 50 kg: 8.8 mCi (325.6 MBq)
<16 yr (52 kg to <70 kg)
- 52-54 kg: 9 mCi (333 MBq)
- 56-58 kg: 9.2 mCi (340.4 MBq)
- 60-62 kg: 9.6 mCi (355.2 MBq)
- 64-66 kg: 9.8 mCi (362.6 MBq)
- 68 kg: 9.9 mCi (366.3 MBq)
Administration
Administer IV over 1-2 minutes, then flush with 0.9% NaCl to ensure full dose delivery
Radiation safety
- Emits radiation and must be handled with appropriate safety measures to minimize radiation exposure to clinical personnel and patients
- Minimize bladder exposure by encourage hydration before and after to permit frequent voiding, particularly for the first 48 hr after administration
Thyroid blockade
- Administer potassium iodide oral solution or Lugol’s solution (equivalent to 100 mg iodide for adults, body-weight adjusted for children) or potassium perchlorate (400 mg for adults, body-weight adjusted for children) to block uptake of iodine 123 by the patient’s thyroid
- Individualize according to patient; blockade may not be needed for patients who have undergone thyroidectomy or those with limited life expectancy
Interactions
Interaction Checker
No Results

Contraindicated
Serious - Use Alternative
Significant - Monitor Closely
Minor

Contraindicated (32)
- amitriptyline
amitriptyline decreases effects of iobenguane I 123 by pharmacodynamic antagonism. Contraindicated. If clinically appropriate, discontinue drugs that decrease uptake of NE for at least 5 half-lives; may cause false-negative imaging results.
- amoxapine
amoxapine decreases effects of iobenguane I 123 by pharmacodynamic antagonism. Contraindicated. If clinically appropriate, discontinue drugs that decrease uptake of NE for at least 5 half-lives; may cause false-negative imaging results.
- atomoxetine
atomoxetine decreases effects of iobenguane I 123 by receptor binding competition. Contraindicated. If clinically appropriate, discontinue drugs that compete for NE receptor sites for at least 5 half-lives; may cause false-negative imaging results.
- clomipramine
clomipramine decreases effects of iobenguane I 123 by pharmacodynamic antagonism. Contraindicated. If clinically appropriate, discontinue drugs that decrease uptake of NE for at least 5 half-lives; may cause false-negative imaging results.
- cocaine topical
cocaine topical decreases effects of iobenguane I 123 by receptor binding competition. Contraindicated. If clinically appropriate, discontinue drugs that compete for NE receptor sites for at least 5 half-lives; may cause false-negative imaging results.
- desipramine
desipramine decreases effects of iobenguane I 123 by pharmacodynamic antagonism. Contraindicated. If clinically appropriate, discontinue drugs that decrease uptake of NE for at least 5 half-lives; may cause false-negative imaging results.
- desvenlafaxine
desvenlafaxine decreases effects of iobenguane I 123 by pharmacodynamic antagonism. Contraindicated. If clinically appropriate, discontinue drugs that decrease uptake of NE for at least 5 half-lives; may cause false-negative imaging results.
- dexmethylphenidate
dexmethylphenidate decreases effects of iobenguane I 123 by receptor binding competition. Contraindicated. If clinically appropriate, discontinue drugs that compete for NE receptor sites for at least 5 half-lives; may cause false-negative imaging results.
- dextroamphetamine
dextroamphetamine decreases effects of iobenguane I 123 by receptor binding competition. Contraindicated. If clinically appropriate, discontinue drugs that compete for NE receptor sites for at least 5 half-lives; may cause false-negative imaging results.
- diethylpropion
diethylpropion decreases effects of iobenguane I 123 by receptor binding competition. Contraindicated. If clinically appropriate, discontinue drugs that compete for NE receptor sites for at least 5 half-lives; may cause false-negative imaging results.
- doxepin
doxepin decreases effects of iobenguane I 123 by pharmacodynamic antagonism. Contraindicated. If clinically appropriate, discontinue drugs that decrease uptake of NE for at least 5 half-lives; may cause false-negative imaging results.
- duloxetine
duloxetine decreases effects of iobenguane I 123 by pharmacodynamic antagonism. Contraindicated. If clinically appropriate, discontinue drugs that decrease uptake of NE for at least 5 half-lives; may cause false-negative imaging results.
- ephedrine
ephedrine decreases effects of iobenguane I 123 by receptor binding competition. Contraindicated. If clinically appropriate, discontinue drugs that compete for NE receptor sites for at least 5 half-lives; may cause false-negative imaging results.
- epinephrine
epinephrine decreases effects of iobenguane I 123 by receptor binding competition. Contraindicated. If clinically appropriate, discontinue drugs that compete for NE receptor sites for at least 5 half-lives; may cause false-negative imaging results.
- epinephrine racemic
epinephrine racemic decreases levels of iobenguane I 123 by receptor binding competition. Contraindicated. If clinically appropriate, discontinue drugs that compete for NE receptor sites for at least 5 half-lives; may cause false-negative imaging results.
- imipramine
imipramine decreases effects of iobenguane I 123 by pharmacodynamic antagonism. Contraindicated. If clinically appropriate, discontinue drugs that decrease uptake of NE for at least 5 half-lives; may cause false-negative imaging results.
- labetalol
labetalol decreases effects of iobenguane I 123 by pharmacodynamic antagonism. Contraindicated. If clinically appropriate, discontinue drugs that decrease uptake of NE for at least 5 half-lives; may cause false-negative imaging results.
- levomilnacipran
levomilnacipran decreases effects of iobenguane I 123 by pharmacodynamic antagonism. Contraindicated. If clinically appropriate, discontinue drugs that decrease uptake of NE for at least 5 half-lives; may cause false-negative imaging results.
- lisdexamfetamine
lisdexamfetamine decreases effects of iobenguane I 123 by receptor binding competition. Contraindicated. If clinically appropriate, discontinue drugs that compete for NE receptor sites for at least 5 half-lives; may cause false-negative imaging results.
- maprotiline
maprotiline decreases effects of iobenguane I 123 by pharmacodynamic antagonism. Contraindicated. If clinically appropriate, discontinue drugs that decrease uptake of NE for at least 5 half-lives; may cause false-negative imaging results.
- methamphetamine
methamphetamine decreases effects of iobenguane I 123 by receptor binding competition. Contraindicated. If clinically appropriate, discontinue drugs that compete for NE receptor sites for at least 5 half-lives; may cause false-negative imaging results.
- milnacipran
milnacipran decreases effects of iobenguane I 123 by pharmacodynamic antagonism. Contraindicated. If clinically appropriate, discontinue drugs that decrease uptake of NE for at least 5 half-lives; may cause false-negative imaging results.
- mirtazapine
mirtazapine decreases effects of iobenguane I 123 by pharmacodynamic antagonism. Contraindicated. If clinically appropriate, discontinue drugs that decrease uptake of NE for at least 5 half-lives; may cause false-negative imaging results.
- nefazodone
nefazodone decreases effects of iobenguane I 123 by pharmacodynamic antagonism. Contraindicated. If clinically appropriate, discontinue drugs that decrease uptake of NE for at least 5 half-lives; may cause false-negative imaging results.
- nortriptyline
nortriptyline decreases effects of iobenguane I 123 by pharmacodynamic antagonism. Contraindicated. If clinically appropriate, discontinue drugs that decrease uptake of NE for at least 5 half-lives; may cause false-negative imaging results.
- phendimetrazine
phendimetrazine decreases effects of iobenguane I 123 by receptor binding competition. Contraindicated. If clinically appropriate, discontinue drugs that compete for NE receptor sites for at least 5 half-lives; may cause false-negative imaging results.
- phentermine
phentermine decreases effects of iobenguane I 123 by receptor binding competition. Contraindicated. If clinically appropriate, discontinue drugs that compete for NE receptor sites for at least 5 half-lives; may cause false-negative imaging results.
- phenylephrine
phenylephrine decreases effects of iobenguane I 123 by receptor binding competition. Contraindicated. If clinically appropriate, discontinue drugs that compete for NE receptor sites for at least 5 half-lives; may cause false-negative imaging results.
- protriptyline
protriptyline decreases effects of iobenguane I 123 by pharmacodynamic antagonism. Contraindicated. If clinically appropriate, discontinue drugs that decrease uptake of NE for at least 5 half-lives; may cause false-negative imaging results.
- serdexmethylphenidate/dexmethylphenidate
serdexmethylphenidate/dexmethylphenidate decreases effects of iobenguane I 123 by receptor binding competition. Contraindicated. If clinically appropriate, discontinue drugs that compete for NE receptor sites for at least 5 half-lives; may cause false-negative imaging results.
- trimipramine
trimipramine decreases effects of iobenguane I 123 by pharmacodynamic antagonism. Contraindicated. If clinically appropriate, discontinue drugs that decrease uptake of NE for at least 5 half-lives; may cause false-negative imaging results.
- venlafaxine
venlafaxine decreases effects of iobenguane I 123 by pharmacodynamic antagonism. Contraindicated. If clinically appropriate, discontinue drugs that decrease uptake of NE for at least 5 half-lives; may cause false-negative imaging results.
Serious - Use Alternative (2)
- methylphenidate
methylphenidate decreases effects of iobenguane I 123 by Other (see comment). Avoid or Use Alternate Drug. Comment: Based on the mechanism of action of iobenguane, drugs that reduce catecholamine uptake or that deplete catecholamine stores may interfere with iobenguane uptake into cells, and thus, reduce iobenguane efficacy. Discontinue interfering drugs for at least 5 half-lives before administration of either the dosimetry or an iobenguane dose.
- pseudoephedrine
pseudoephedrine decreases effects of iobenguane I 123 by receptor binding competition. Avoid or Use Alternate Drug. If clinically appropriate, discontinue drugs that compete for NE receptor sites for at least 5 half-lives; may cause false-negative imaging results. Do not administer pseudoephedrine until at least 7 days after each iobenguane dose.
Monitor Closely (0)
Minor (0)
Adverse Effects
Frequency Not Defined
Dizziness
Rash
Pruritus
Flushing
Injection site hemorrhage
Postmarketing Reports
Hypersensitivity
Warnings
Contraindications
Hypersensitivity
Cautions
Emits radiation and must be handled with appropriate safety measures for radiopharmaceuticals
Fully investigate history of allergic response to previous contrast agents or iodine
Contains benzyl alcohol (10.3 mg/mL); associated with fatal gasping syndrome in premature infants and infants of low birth weight; excessive amounts associated with toxicity (hypotension, metabolic acidosis), particularly in neonates, and increased incidence of kernicterus in small preterm infants
Increased radiation exposure in patients with severe renal impairment; cleared by glomerular filtration and is not dialyzable
Failure to block thyroid uptake of iodine 123 may result in increased long-term risk for thyroid neoplasia; administer thyroid blocking medications (see Administration)
Drugs that interfere with norepinephrine uptake or retention may cause false negative imaging results; if clinically feasible, discontinue these drugs before administering iobenguane I 123
Individuals with conditions that affect the sympathetic nervous system (eg, Parkinson disease, multiple system atrophy) may show decreased cardiac uptake of iobenguane I 123 independent of heart disease
Assess pulse and blood pressure before and intermittently for 30 minutes following administration
Pregnancy & Lactation
Pregnancy
Radioactive iodine products cross the placenta and can permanently impair fetal thyroid function; administration of an appropriate thyroid blocking agent is recommended before use in a pregnant woman to protect the woman and fetus from accumulation of I 123
There are no available data on use in pregnant women to evaluate for a drug-associated risk of major birth defects, miscarriage or adverse maternal or fetal outcomes
Drug contains 10.3 mg/mL of benzyl alcohol; because benzyl alcohol is rapidly metabolized by a pregnant woman, benzyl alcohol exposure in the fetus is unlikely; however, adverse reactions have occurred in premature neonates and low birth weight infants who received intravenously administered benzyl alcohol-containing drugs
Animal data
- Animal reproduction studies have not been conducted; all radiopharmaceuticals have potential to cause fetal harm depending on fetal stage of development and magnitude of radiation dose; advise pregnant women of potential risks of fetal exposure to radiation doses with administration of therapy
Lactation
Iodine 123 (I 123), the radionuclide in the drug, is present in human milk; there is no information on effects on breastfed infant or on milk production; advise a lactating woman to interrupt breastfeeding and pump and discard breastmilk for at least 6 days (>10 physical half-lives) after administration in order to minimize radiation exposure to a breastfed infant
Pregnancy Categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk. C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done. D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk. X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist. NA: Information not available.Pharmacology
Mechanism of Action
Iobenguane is similar in structure to guanethidine and the neurotransmitter norepinephrine (NE), and is therefore subject to the same uptake and accumulation pathways as NE
Diagnostic radiopharmaceutical contains only a small quantity of iobenguane that is not expected to produce a pharmacodynamic effect
Iobenguane is taken up by the NE transporter in adrenergic nerve terminals and stored in the presynaptic storage vesicles; accumulates in adrenergically innervated tissues (eg, adrenal medulla, salivary glands, heart, liver, spleen, lungs) as well as tumors derived from the neural crest
Metabolism
Metabolic process not well characterized and pharmacologic activity of metabolites has not been studied
Metabolites: Radioiodinated metabolite m-iodohippuric acid (MIHA); free radioiodide
Elimination
Half-life: 13.2 hr (I 123)
Dialyzable: No
Excretion: 70-90% (unchanged iobenguane) in urine within 4 days
Images
Patient Handout
iobenguane sulfate I-123 intravenous
NO MONOGRAPH AVAILABLE AT THIS TIME
USES: Consult your pharmacist.
HOW TO USE: Consult your pharmacist.
SIDE EFFECTS: Consult your pharmacist.In the US -Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.
PRECAUTIONS: Consult your pharmacist.
DRUG INTERACTIONS: Consult your pharmacist.Keep a list of all your medications with you, and share the list with your doctor and pharmacist.
OVERDOSE: If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center.
NOTES: No monograph available at this time.
MISSED DOSE: Consult your pharmacist.
STORAGE: Consult your pharmacist.Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company for more details about how to safely discard your product.
Information last revised July 2016. Copyright(c) 2023 First Databank, Inc.
IMPORTANT: HOW TO USE THIS INFORMATION: This is a summary and does NOT have all possible information about this product. This information does not assure that this product is safe, effective, or appropriate for you. This information is not individual medical advice and does not substitute for the advice of your health care professional. Always ask your health care professional for complete information about this product and your specific health needs.
Formulary
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