Cardiogen-82

None.

Specific drug-drug interactions have not been studied.

Pregnancy

Pregnancy Category C

Animal reproductive studies have not been conducted with rubidium Rb 82 chloride injection. It is also not known whether rubidium Rb 82 chloride injection can cause fetal harm when administered to a pregnant woman; however, all radiopharmaceuticals have the potential to cause fetal harm depending on the fetal stage of development and the magnitude of the radiation dose. If considering rubidium Rb 82 chloride injection administration to a pregnant woman, inform the patient about the potential for adverse pregnancy outcomes based on the radiation dose from rubidium Rb-82 and the gestational timing of exposure. Administer rubidium Rb-82 to a pregnant woman only if clearly needed.

Nursing Mothers

It is not known whether rubidium Rb 82 chloride injection is excreted in human milk. Due to the short half-life of rubidium Rb-82 (75 seconds) it is unlikely that the drug would be excreted in human milk during lactation. However, because many drugs are excreted in human milk, caution should be exercised when rubidium Rb-82 chloride injection is administered to nursing women. Do not resume breastfeeding until one hour after the last infusion.

Pediatric Use

Rubidium Rb 82 chloride injection safety and effectiveness in pediatric patients have not been established.

Geriatric Use

In elderly patients with a clinically important decrease in cardiac function, lengthen the delay between infusion and image acquisition [see Dosage and Administration (2.2)]. Observe for the possibility of fluid overload [see Warnings and Precautions (5.3)].

Renal Impairment

Reductions in renal function are not anticipated to alter clearance of rubidium Rb 82 chloride injection because Rb-82 decays to stable Kr-82 with a half-life of 75 seconds and Kr-82 is exhaled through the lungs.

Hepatic Impairment

Reductions in hepatic function are not anticipated to alter clearance of rubidium Rb 82 chloride injection.

Chemical Characteristics

Cardiogen-82 contains accelerator-produced Sr-82 adsorbed on stannic oxide in a lead-shielded column and provides a means for obtaining sterile nonpyrogenic solutions of rubidium Rb 82 chloride injection. The chemical form of Rb-82 is 82RbCl.

The amount (millicuries) of Rb-82 obtained in each elution will depend on the potency of the generator.
When eluted at a rate of 50 mL/minute, each generator eluate at the end of elution should not contain more than 0.02 microcurie of Sr-82 and not more than 0.2 microcurie of Sr-85 per millicurie of rubidium Rb 82 chloride injection, and not more than 1 microgram of tin per mL of eluate.

Physical Characteristics

Rb-82 decays by positron emission and associated gamma emission with a physical half-life of 75 seconds.4 Table 4 shows the annihilation photons released following positron emission which are useful for detection and imaging studies.

The decay modes of Rb-82 are: 95.5% by positron emission, resulting in the production of annihilation radiation, i.e., two 511 keV gamma rays; and 4.5% by electron capture, resulting in the emission of “prompt” gamma rays of predominantly 776.5 keV. Both decay modes lead directly to the formation of stable Kr-82.4

The specific gamma ray constant for Rb-82 is 6.1 R/hour-millicurie at 1 centimeter. The first half-value layer is 0.7 centimeter of lead (Pb). Table 5 shows a range of values for the relative attenuation of the radiation emitted by this radionuclide that results from interposition of various thicknesses of lead.5 For example, the use of a 7.0 centimeter thickness of Pb will attenuate the radiation emitted by a factor of about 1,000.

Sr-82 (half-life of 25 days (600 hrs)) decays to Rb-82. To correct for physical decay of Sr-82, Table 6 shows the fractions that remain at selected intervals after the time of calibration.

To correct for physical decay of Rb-82, Table 1 shows the fraction of Rb-82 remaining in all 15 second intervals up to 300 seconds after time of calibration [see Dosage and Administration (2.5)].