Product Information

Registration Status: Active

THALLOUS CHLORIDE (TL201) INJECTION 37 MBQ/ML is approved to be sold in Singapore with effective from 1998-09-30. It is marketed by QT INSTRUMENTS (S) PTE LTD, with the registration number of SIN10153P.

This product contains Thallous Chloride 37 MBq/ml in the form of INJECTION. It is approved for INTRAVENOUS use.

This product is manufactured by Mallinckrodt Medical B.V. in NETHERLANDS.

It is a Prescription Only Medicine that can only be obtained from a doctor or a dentist, or a pharmacist with a prescription from a Singapore-registered doctor or dentist.

Thallous Chloride


Thallous chloride (also known as Thallium(I) chloride) is a chemical compound with the formula TlCl. This colourless solid is an intermediate in the isolation of thallium from its ores. Typically, an acidic solution of thallium(I) sulfate is treated with hydrochloric acid to precipitate insoluble thallium(I) chloride. This solid crystallizes in the caesium chloride motif. It is used as a diagnostic radiopharmaceutical. It is used for diagnosis of heart and parathyroid problems. The following are among the possible side effects: Blurred vision, chest pain or discomfort, chills, confusion, cough, difficulty with breathing, difficulty with swallowing, and dizziness.


For use as a diagnostic radiopharmaceutical. It is indicated to help diagnose heart disease (eg, coronary artery disease, heart attack). It is also used for the diagnosis of parathyroid problems.

Mechanism of Action

Thallous Chloride TI201 without carrier, accumulates in the heart (myocardium) in a similar way to that of potassium. Thallous Chloride Tl 201 images have been found to visualize areas of infarction as “cold” or nonlabeled regions which are confirmed by electrocardiographic and enzyme changes. Regions of transient myocardial ischemia corresponding to areas perfused by coronary arteries with partial stenoses have been visualized when Thallous Chloride Tl 201 was administered in conjunction with an exercise stress test. Anatomic configurations may interfere with visualization of the right coronary artery.


After IV administration, thallous chloride clears rapidly from the blood, with maximum concentration in the myocardium after about 10 min. Only 5-8% of injected activity remained in the blood, following 5 minutes of intravenous administration.
3–10 L/kg
Data not found


Approximately 4-8% of the injected dose was excreted in the urine in the first 24 hours. The whole body disappearance half-time was 9.8 ± 2.5 days. Kidney concentration was found to be about 3 percent of the injected activity and the testicular content was 0.15 percent. Net thyroid activity was determined to be only 0.2 percent of the injected dose, and the activity disappeared in 24 hours. From anterior and posterior whole-body scans, it was determined that about 45 percent of the injected dose was in the large intestines and contiguous structures (liver, kidneys, abdominal musculature).


LD50 (mouse): 24 mg/kg. Minimum lethal dose (Human): 8 mg/kg. Thallium inhibits enzymes, but nothing is really known of a biochemical lesion. In fatal cases, there usually is extensive peripheral paralysis and cardiovascular involvement. The immediate cause of death may be peripheral respiratory failure of cardiac arrest.

Active Ingredient/Synonyms

Thallium chloride | thallium monochloride | Thallium(I) chloride | Thallous Chloride Tl-201 | Thallous Chloride |

Source of information: Drugbank (External Link). Last updated on: 3rd July 18. *Trade Name used in the content below may not be the same as the HSA-registered product.


  1. Health Science Authority of Singapore - Reclassified POM
  2. Drugbank