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Thallous chloride tl 201 (By injection)

Thallous Chloride Tl 201 (THAL-us KLOR-ide TI 201)

Helps diagnose a heart attack or blocked arteries of the heart during planar scintigraphy or single-photon emission computed tomography (SPECT) scan. Also helps diagnose parathyroid problems.

Brand Name(s):

There may be other brand names for this medicine.

When This Medicine Should Not Be Used:

This medicine is not right for everyone. You should not receive it if you had an allergic reaction to thallous chloride Tl 201.

How to Use This Medicine:


  • A doctor or other trained health professional will give you this medicine. It is given through a needle placed in one of your veins just before you have a planar scintigraphy or SPECT scan.
  • Your doctor may ask you not to eat or drink anything for several hours before your test.
  • You may be asked to sit upright while you receive your injection.
  • Your planar scintigraphy or SPECT scan will be performed 10 to 20 minutes after you receive this medicine.

Drugs and Foods to Avoid:

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

Warnings While Using This Medicine:

  • Tell your doctor if you are pregnant or if you have breathing or lung problems, heart rhythm problems, high or low blood pressure, or a history of heart attack or stroke. Tell your doctor if you have a latex allergy.
  • Do not breastfeed for 2 weeks after you receive this medicine.
  • You may receive a medicine to make your heart beat faster. This is called a pharmacologic stress test. The stress test is used together with the planar scintigraphy or SPECT scan to show how well your heart muscle works when it is stressed.
  • You will be exposed to radiation when you receive this medicine. Talk to your doctor if you have any questions about this.
  • Your doctor will check your progress and the effects of this medicine at regular visits. Keep all appointments.

Possible Side Effects While Using This Medicine:

Call your doctor right away if you notice any of these side effects:

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
  • Chest pain, trouble breathing
  • Fast, slow, or pounding heartbeat
  • Fever or chills
  • Lightheadedness or fainting
  • Tremors

If you notice these less serious side effects, talk with your doctor:

  • Blurred vision, red, irritated eyes
  • Increased sweating
  • Nausea, vomiting, or diarrhea
  • Pain, itching, burning, swelling, or a lump under your skin where the needle is placed

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088

Last Updated: 5/1/2020

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