Ioflupane (123I) ROTOP

Radioactive diagnostic agent for DaTscan SPECT brain imaging

Prescription Only Radiopharmaceutical
Active Ingredient
Ioflupane (123I)
Dosage Form
Solution for injection
Strength
74 MBq/ml
Administration
Intravenous injection
Brand Name
Ioflupane (123I) ROTOP
Manufacturer
ROTOP Pharmaka GmbH
Reviewed by iMedic Medical Board
Published:
Updated:
Evidence Level 1A

Ioflupane (123I) ROTOP is a radiopharmaceutical diagnostic agent used in single photon emission computed tomography (SPECT) brain imaging, commonly known as a DaTscan. It binds to dopamine transporters in the brain, allowing physicians to visualize the integrity of dopaminergic pathways. This imaging technique is primarily used to help distinguish parkinsonian syndromes from essential tremor and to differentiate probable dementia with Lewy bodies from Alzheimer's disease. This medication is administered only in specialized nuclear medicine facilities by authorized healthcare professionals.

Quick Facts

Active Ingredient
Ioflupane (123I)
Drug Class
Radiopharmaceutical
Route
IV Injection
Primary Use
DaTscan SPECT
Available Form
74 MBq/ml
Prescription Status
Rx Only

Key Takeaways

  • Ioflupane (123I) ROTOP is a radioactive tracer used exclusively for diagnostic DaTscan SPECT brain imaging — it is not a treatment medication.
  • DaTscan helps differentiate Parkinson's disease and other parkinsonian syndromes from essential tremor by visualizing dopamine transporter density in the striatum.
  • The procedure is performed as a single intravenous injection in a nuclear medicine facility, with SPECT imaging 3–6 hours later.
  • Several medications (including amphetamines, bupropion, methylphenidate, and sertraline) must be discontinued before the scan as they can affect results.
  • Side effects are generally mild and uncommon; the radiation exposure is low and comparable to other standard nuclear medicine procedures.

What Is Ioflupane (123I) ROTOP and What Is It Used For?

Quick Answer: Ioflupane (123I) ROTOP is a radioactive diagnostic agent injected intravenously before a DaTscan SPECT brain scan. It binds to dopamine transporters in the brain's striatum, enabling doctors to assess dopaminergic neuron function and help diagnose conditions like Parkinson's disease and dementia with Lewy bodies.

Ioflupane (123I) ROTOP belongs to a class of medications known as radiopharmaceuticals — substances that contain a radioactive isotope and are used for diagnostic imaging purposes. The active compound, ioflupane, is labeled with iodine-123 (123I), a gamma-emitting radioisotope with a half-life of approximately 13.2 hours. This relatively short half-life ensures that the radiation exposure to the patient is kept to a minimum while still allowing sufficient time for high-quality imaging.

The primary clinical application of ioflupane (123I) is in dopamine transporter (DAT) imaging, commonly referred to as a DaTscan. The dopamine transporter is a protein located on the surface of presynaptic dopaminergic neurons in the striatum (a region deep within the brain comprising the caudate nucleus and putamen). In healthy individuals, these transporters are abundant. However, in neurodegenerative conditions that affect the nigrostriatal dopaminergic pathway — most notably Parkinson's disease — there is a progressive loss of these neurons, resulting in reduced DAT density.

By binding to these transporters and emitting gamma radiation detectable by a SPECT camera, ioflupane (123I) allows physicians to create detailed images of DAT distribution in the brain. This information is clinically valuable in two primary scenarios:

  • Differentiating parkinsonian syndromes from essential tremor: Parkinson's disease, progressive supranuclear palsy (PSP), multiple system atrophy (MSA), and corticobasal degeneration all involve degeneration of dopaminergic neurons and will typically show reduced DAT uptake. In contrast, essential tremor does not involve dopaminergic loss, so the DaTscan will appear normal. This distinction is clinically important because the treatment approaches and prognoses differ significantly.
  • Differentiating dementia with Lewy bodies (DLB) from Alzheimer's disease: DLB is characterized by dopaminergic degeneration similar to Parkinson's disease, whereas Alzheimer's disease does not primarily affect the dopamine system. A DaTscan showing reduced striatal uptake supports a diagnosis of DLB over Alzheimer's disease, which can influence treatment decisions and disease management strategies.

It is important to understand that ioflupane (123I) ROTOP is a purely diagnostic tool. It does not treat or cure any condition. The scan results must always be interpreted within the broader clinical context, including the patient's symptoms, neurological examination, and other diagnostic findings. A DaTscan alone cannot make a definitive diagnosis of Parkinson's disease but serves as a valuable adjunctive test in the diagnostic workup.

Clinical Note: DaTscan cannot differentiate between different types of parkinsonian syndromes (e.g., it cannot distinguish Parkinson's disease from MSA or PSP), as all of these conditions involve nigrostriatal dopaminergic loss. The scan is most useful for distinguishing conditions with dopaminergic degeneration from those without it.

What Should You Know Before Receiving Ioflupane (123I) ROTOP?

Quick Answer: Before a DaTscan, your doctor needs to know about all medications you take (especially those affecting dopamine transporters), any allergies, whether you are pregnant or breastfeeding, and your kidney function. Thyroid-blocking medication is typically given before the injection to protect your thyroid gland from radioactive iodine uptake.

Because ioflupane (123I) ROTOP is a radiopharmaceutical administered in a controlled clinical setting, there are several important considerations that healthcare professionals and patients must be aware of before the procedure. Your nuclear medicine physician will evaluate your suitability for the scan and provide specific instructions.

Contraindications

There are few absolute contraindications to DaTscan imaging, but the following situations require careful consideration:

  • Known hypersensitivity: Patients with a documented allergy to ioflupane, iodine, or any of the excipients in the formulation should not receive this product. Although allergic reactions are very rare, anaphylaxis is a theoretical risk with any injectable substance.
  • Pregnancy: Radiopharmaceuticals are generally contraindicated during pregnancy due to the risk of radiation exposure to the developing fetus. If pregnancy is suspected, it should be ruled out before the procedure.

Warnings and Precautions

Several important precautions should be observed when using ioflupane (123I) ROTOP:

  • Thyroid blockade: Free radioactive iodine-123 released during the metabolism of ioflupane can accumulate in the thyroid gland. To minimize thyroid radiation exposure, patients are typically given potassium iodide (or potassium perchlorate) approximately one hour before the injection. This blocks thyroid uptake of free iodine-123.
  • Radiation safety: As with all radiopharmaceuticals, appropriate radiation safety precautions must be observed. The product should only be handled and administered by personnel authorized to work with radioactive materials, in facilities equipped with appropriate shielding and waste disposal systems.
  • Renal impairment: Ioflupane (123I) and its metabolites are primarily excreted through the kidneys. Patients with significant renal impairment may have delayed clearance, potentially affecting image quality and radiation dosimetry. Your physician may need to adjust the timing of imaging or take additional precautions.
  • Hepatic impairment: Severe liver disease may alter the metabolism of ioflupane, but clinical data in this population are limited. The physician should weigh the diagnostic benefit against potential risks.
  • Pediatric use: The safety and efficacy of ioflupane (123I) in children and adolescents under 18 years of age have not been established. Use in this population is not recommended unless the potential diagnostic benefit clearly outweighs the risk of radiation exposure.

Pregnancy and Breastfeeding

Radiopharmaceutical procedures are generally avoided during pregnancy. If a DaTscan is considered medically necessary in a woman of childbearing age, pregnancy must be excluded before the procedure. The radiation dose to the uterus from a standard DaTscan is estimated to be low, but the precautionary principle applies strongly in this context.

Breastfeeding should be interrupted after administration of ioflupane (123I). Current guidelines from the European Association of Nuclear Medicine (EANM) recommend discontinuing breastfeeding for at least 3 days after the injection to prevent transfer of radioactivity to the infant through breast milk. Expressed milk during this period should be discarded. The decision about when to resume breastfeeding should be made in consultation with the nuclear medicine physician.

Important Warning: Always inform your doctor if you are pregnant, suspect you may be pregnant, or are breastfeeding. Radiopharmaceutical procedures carry risks of radiation exposure to the unborn child or nursing infant. Alternative diagnostic approaches should be considered when possible.

How Does Ioflupane (123I) ROTOP Interact with Other Drugs?

Quick Answer: Several medications that bind to the dopamine transporter can interfere with DaTscan results, leading to false-negative findings. These include amphetamines, bupropion, cocaine, mazindol, methylphenidate, phentermine, sertraline, and benzatropine. These drugs may need to be discontinued before the procedure.

Drug interactions with ioflupane (123I) are primarily pharmacodynamic rather than pharmacokinetic. Because the diagnostic value of the scan depends on ioflupane binding to the dopamine transporter (DAT), any drug that also binds to or otherwise affects DAT can potentially alter the scan results. These medications can compete with ioflupane for binding sites on the transporter, potentially reducing striatal uptake and leading to falsely abnormal or falsely normal results.

The clinical significance of these interactions varies depending on the drug's binding affinity for DAT, the dose used, and how long it has been taken. Your nuclear medicine physician will carefully review your medication list and provide specific guidance on which medications to discontinue and for how long before the scan.

Major Interactions

The following medications have well-documented interactions with ioflupane (123I) and should typically be discontinued before DaTscan imaging. The recommended washout periods vary based on the drug's pharmacokinetics:

Known Drug Interactions with Ioflupane (123I)
Drug Drug Class Mechanism Recommended Washout
Amphetamines CNS stimulant DAT substrate; increases synaptic dopamine At least 2 weeks
Benzatropine Anticholinergic DAT binding affinity At least 5 days
Bupropion Antidepressant (NDRI) DAT and NET inhibitor At least 8 days
Cocaine CNS stimulant Potent DAT inhibitor At least 2 weeks
Mazindol Anorectic DAT inhibitor At least 5 days
Methylphenidate CNS stimulant DAT inhibitor At least 2 weeks
Phentermine Anorectic DAT substrate; dopamine release At least 2 weeks
Sertraline Antidepressant (SSRI) DAT binding at high doses At least 6 weeks

Minor or No Significant Interactions

Several commonly prescribed medications for Parkinson's disease and related conditions do not significantly interfere with DaTscan results and generally do not need to be discontinued:

  • Levodopa/carbidopa: Does not bind to DAT and does not affect scan interpretation.
  • Dopamine agonists (pramipexole, ropinirole, rotigotine): Act on postsynaptic dopamine receptors, not DAT.
  • MAO-B inhibitors (selegiline, rasagiline): Inhibit dopamine metabolism but do not significantly bind DAT at therapeutic doses.
  • COMT inhibitors (entacapone, tolcapone): Act peripherally on dopamine metabolism and do not affect DAT binding.
  • Amantadine: Primarily acts through NMDA receptor antagonism and does not significantly interfere with DAT imaging.
  • Benzodiazepines: No interaction with the dopaminergic system.
  • Most SSRIs (except sertraline at high doses): Citalopram, escitalopram, fluoxetine, and paroxetine have negligible affinity for DAT at therapeutic concentrations.
Important: Always provide your nuclear medicine physician with a complete list of all medications you are taking, including over-the-counter drugs, supplements, and any recreational substances. Even medications not listed above may theoretically affect the scan under certain circumstances.

What Is the Correct Dosage of Ioflupane (123I) ROTOP?

Quick Answer: The standard adult dose is 111–185 MBq (3–5 mCi) administered as a single slow intravenous injection over 15–20 seconds. SPECT imaging is performed 3 to 6 hours after injection. The dose is not adjusted for weight in adults. Pediatric use is not established.

Ioflupane (123I) ROTOP is administered exclusively by qualified healthcare professionals in licensed nuclear medicine departments. It is not a medication that patients self-administer or take home. The dosing is standardized and differs fundamentally from typical pharmaceutical dosing because the "dose" refers to the amount of radioactivity administered, measured in megabecquerels (MBq) or millicuries (mCi), rather than milligrams of active substance.

Adults

Standard Adult Dose

Recommended dose: 111–185 MBq (3–5 mCi) intravenous injection

Injection rate: Slow intravenous injection over 15–20 seconds

Volume: Typically 2.5 ml of solution (at the reference activity of 74 MBq/ml)

Imaging window: SPECT acquisition 3–6 hours post-injection

The injection should be given through a short indwelling venous cannula to minimize the possibility of extravasation (leakage of the radioactive substance into surrounding tissue). If extravasation occurs, the injection site should be irrigated and the imaging may need to be rescheduled, as local accumulation of tracer can potentially affect image interpretation.

Prior to the injection, patients typically receive a thyroid-blocking agent (such as potassium iodide or potassium perchlorate) approximately 1 hour before the ioflupane injection. This is to prevent the thyroid gland from absorbing any free radioactive iodine-123 released during metabolism of the compound.

Children and Adolescents

Pediatric Population

The safety and efficacy of ioflupane (123I) in patients under 18 years of age have not been established. There are no adequate data from clinical trials in the pediatric population. Use in children and adolescents is therefore not recommended unless the treating physician determines that the potential diagnostic benefit clearly outweighs the risk associated with radiation exposure in a developing individual.

Elderly Patients

Elderly Dose (65+ years)

No dose adjustment is required for elderly patients. The standard adult dose of 111–185 MBq applies. However, clinicians should be aware that normal age-related decline in striatal dopamine transporter density occurs and must be taken into account when interpreting scan results. Reference databases typically include age-matched normative data to help distinguish pathological from age-related changes.

Missed Dose

The concept of a "missed dose" does not apply to ioflupane (123I) ROTOP in the conventional sense, as it is administered as a single injection during a scheduled medical procedure. If the procedure is cancelled or postponed, a new appointment will be scheduled. The prepared radiopharmaceutical has a limited shelf life due to the decay of iodine-123 (half-life ~13.2 hours), so a new preparation will typically be needed if the appointment is significantly delayed.

Overdose

Overdose with ioflupane (123I) is unlikely given that it is administered in a controlled clinical environment by trained professionals. However, in the event of an inadvertent radiation overdose, the absorbed radiation dose to the patient should be calculated. Encouraging frequent urination and adequate hydration can help accelerate the elimination of radioactivity from the body. There is no specific antidote. The main concern with overdose is increased radiation exposure rather than pharmacological toxicity, as the mass of ioflupane administered is pharmacologically negligible.

Dosage Summary by Patient Group
Patient Group Recommended Dose Route Notes
Adults (18–64 years) 111–185 MBq IV injection Single dose; image 3–6 h post-injection
Elderly (65+ years) 111–185 MBq IV injection No dose adjustment; age-matched reference data used
Children (<18 years) Not established N/A Safety and efficacy not established
Renal impairment 111–185 MBq IV injection Caution; may have delayed clearance

What Are the Side Effects of Ioflupane (123I) ROTOP?

Quick Answer: Side effects of ioflupane (123I) ROTOP are generally uncommon and mild. The most commonly reported effects include headache, vertigo (dizziness), and increased appetite. Serious adverse reactions such as hypersensitivity are very rare. The main safety consideration relates to radiation exposure, which is kept to a minimum through careful dose selection.

Clinical trials and post-marketing surveillance have shown that ioflupane (123I) is generally well-tolerated. The chemical dose of ioflupane administered is extremely small (in the microgram range) and is pharmacologically inactive at these concentrations. Therefore, most potential adverse effects relate to the radioactive component rather than the chemical compound itself.

The following side effects have been reported in clinical studies and post-marketing experience. They are classified according to their frequency using the standard medical convention defined by the Council for International Organizations of Medical Sciences (CIOMS):

Common

May affect up to 1 in 10 patients
  • Headache

Uncommon

May affect up to 1 in 100 patients
  • Vertigo (dizziness)
  • Increased appetite
  • Dysgeusia (altered taste)
  • Formication (sensation of insects crawling on the skin)
  • Dry mouth
  • Nausea

Rare

May affect up to 1 in 1,000 patients
  • Hypersensitivity reactions (including skin rash, pruritus, urticaria)
  • Injection site pain or erythema
  • Intense hunger

It is important to note that the radiation exposure associated with the procedure also carries a very small theoretical risk of long-term effects, including a marginally increased lifetime risk of cancer. However, this risk is extremely low and is considered to be greatly outweighed by the diagnostic benefit of the procedure. The effective dose from a standard DaTscan (185 MBq) is approximately 4.35 mSv, which is comparable to about 1–2 years of natural background radiation exposure and is in the same range as many other routine nuclear medicine and CT procedures.

Radiation dosimetry studies have shown that the organs receiving the highest absorbed doses are the lungs, liver, and urinary bladder wall, with the striatum (the target organ for imaging) receiving a relatively modest dose. Encouraging patients to drink fluids and urinate frequently after the procedure helps minimize bladder wall exposure.

Seek Immediate Medical Attention If: You experience difficulty breathing, facial or throat swelling, severe itching or hives, rapid heartbeat, or a feeling of faintness after the injection. These could be signs of a rare but serious allergic reaction (anaphylaxis).

The nuclear medicine department where you receive your scan will have emergency equipment and trained staff available to manage any acute adverse reactions. You will typically be monitored for a brief period after the injection before being allowed to leave for the imaging appointment.

How Should Ioflupane (123I) ROTOP Be Stored?

Quick Answer: Ioflupane (123I) ROTOP is stored in the nuclear medicine department under strict conditions. It must be kept below 25°C, within radiation shielding, and used within its assigned expiry time. Patients do not need to store this medication at home — it is prepared and administered entirely within the hospital setting.

As a radiopharmaceutical, ioflupane (123I) ROTOP has very specific storage requirements that are handled entirely by the nuclear medicine facility. Patients will never be asked to store, transport, or handle this product themselves. The following information is provided for completeness and educational purposes:

  • Temperature: Store below 25°C (77°F). Do not freeze.
  • Radiation shielding: The product must be stored within appropriate lead shielding to minimize radiation exposure to personnel.
  • Shelf life: Due to the radioactive decay of iodine-123 (half-life ~13.2 hours), the product has a limited shelf life. It must be used within the timeframe specified on the label, which is calibrated to account for radioactive decay from the time of manufacture.
  • Light protection: Protect from direct light exposure.
  • Container: Store in the original container. Do not use if the solution appears discolored, contains particulate matter, or if the container integrity is compromised.

After administration, the patient will excrete the radioactive substance primarily through the kidneys. Standard radiation safety advice applies: patients should maintain good hygiene, wash hands thoroughly after using the bathroom, and ensure adequate hydration for the first 24–48 hours after the procedure to promote faster clearance of radioactivity.

Unused radiopharmaceutical product must be disposed of in accordance with national regulations for radioactive waste. This is handled by the nuclear medicine department and does not concern the patient.

What Does Ioflupane (123I) ROTOP Contain?

Quick Answer: The active substance is ioflupane labeled with radioactive iodine-123. Each milliliter contains 74 MBq of ioflupane (123I) at the reference time. Excipients include acetic acid, sodium acetate, and ethanol in a sterile aqueous solution.

Understanding the composition of ioflupane (123I) ROTOP helps patients and healthcare professionals appreciate what is being administered. The product is a clear, colorless solution intended for intravenous injection.

Active Substance

The active ingredient is ioflupane (123I), also known by its chemical name as N-ω-fluoropropyl-2β-carbomethoxy-3β-(4-[123I]iodophenyl)nortropane, or 123I-FP-CIT. The activity at reference time is 74 MBq per ml. The chemical amount of ioflupane in each dose is in the microgram range — far below any pharmacologically active concentration. Its role is solely as a carrier for the radioactive iodine-123 label to enable SPECT imaging.

Excipients (Inactive Ingredients)

  • Acetic acid (glacial): Used as a pH buffer to maintain solution stability.
  • Sodium acetate trihydrate: Buffer component for pH adjustment.
  • Ethanol (anhydrous): Co-solvent to maintain ioflupane in solution. The ethanol content per dose is very low and clinically insignificant.
  • Water for injections: Solvent base for the sterile injectable solution.

The product does not contain any preservatives, antimicrobial agents, or added colorings. The pH of the solution is typically in the range of 4.0 to 6.0. The solution should be clear and colorless; if any particles are visible or if the solution appears discolored, it should not be used.

Note on Radioactivity: The radioactivity of iodine-123 decreases over time due to natural radioactive decay (half-life approximately 13.2 hours). This means that the product's radioactive content at the time of administration will differ from the labeled activity at the reference time. The nuclear medicine department will calculate the appropriate volume to inject based on the desired activity at the time of administration.

Frequently Asked Questions About Ioflupane (123I) ROTOP

References

This article is based on the following peer-reviewed sources and official guidelines:

  1. European Medicines Agency (EMA). DaTscan (Ioflupane 123I) – Summary of Product Characteristics. EMA/CHMP. Last updated 2024.
  2. Darcourt J, Booij J, Tatsch K, et al. EANM procedure guidelines for brain neurotransmission SPECT using 123I-labelled dopamine transporter ligands, version 2. Eur J Nucl Med Mol Imaging. 2010;37(2):443–450.
  3. Djang DSW, Janssen MJR, Bohnen N, et al. SNM practice guideline for dopamine transporter imaging with 123I-ioflupane SPECT 1.0. J Nucl Med. 2012;53(1):154–163.
  4. Benamer HTS, Patterson J, Wyper DJ, Hadley DM, Macphee GJ, Grosset DG. Correlation of Parkinson's disease severity and duration with 123I-FP-CIT SPECT striatal uptake. Mov Disord. 2000;15(4):692–698.
  5. McKeith IG, Boeve BF, Dickson DW, et al. Diagnosis and management of dementia with Lewy bodies: Fourth consensus report. Neurology. 2017;89(1):88–100.
  6. Catafau AM, Tolosa E; DaTSCAN Clinically Uncertain Parkinsonian Syndromes Study Group. Impact of dopamine transporter SPECT using 123I-Ioflupane on diagnosis and management of patients with clinically uncertain Parkinsonian syndromes. Mov Disord. 2004;19(10):1175–1182.
  7. International Commission on Radiological Protection (ICRP). Radiation dose to patients from radiopharmaceuticals. ICRP Publication 128. Ann ICRP. 2015;44(2S).
  8. World Health Organization (WHO). WHO Model List of Essential Medicines – 23rd List. Geneva: WHO; 2023.
  9. Postuma RB, Berg D, Stern M, et al. MDS clinical diagnostic criteria for Parkinson's disease. Mov Disord. 2015;30(12):1591–1601.
  10. Ba F, Martin WRW. Dopamine transporter imaging as a diagnostic tool for parkinsonism and related disorders in clinical practice. Parkinsonism Relat Disord. 2015;21(2):87–94.

Editorial Team

This article has been written and reviewed by the iMedic Medical Editorial Team, which includes board-certified specialists in nuclear medicine, neurology, and clinical pharmacology.

Medical Writing

iMedic Medical Editorial Team — Specialists in nuclear medicine and neuroimaging with clinical and academic experience in dopamine transporter imaging.

Medical Review

iMedic Medical Review Board — Independent panel of physicians who verify accuracy, completeness, and adherence to international guidelines (EMA, SNMMI, EANM).

Evidence standard: All claims in this article are supported by Level 1A evidence (systematic reviews and randomized controlled trials) or official regulatory documents (EMA SmPC). The content follows the GRADE evidence framework and is free from commercial influence.

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