Technetium Tc 99m Medronate

Technetium Tc 99m medronate may be used as a bone imaging agent to delineate areas of altered osteogenesis.

None known.

This class of compounds is known to complex cations such as calcium. Particular caution should be used with patients who have or who may be predisposed to hypocalcemia (i.e., alkalosis). Preliminary reports indicate interference with brain scans using sodium pertechnetate Tc 99m injection which have been preceded by a bone scan using an agent containing stannous ions. This interference may result in false-positive or false-negative brain scans. It is recommended, where feasible, that brain scans precede bone imaging procedures. The biodistribution of technetium Tc 99m medronate may be altered in the presence of high levels of certain cations (iron, calcium, and aluminum). This may result in reduced uptake of radionuclide in the skeleton and increased extraosseal uptake, which may potentially degrade imaging quality. High levels of these cations may be caused by concomitant medications or medical conditions (e.g., iron overload, hypercalcemia, etc.). Most cases were observed after iron infusion. (See PRECAUTIONS, Drug Interactions .)

General The contents of the kit before preparation are not radioactive. However, after the sodium pertechnetate Tc 99m injection is added, adequate shielding of the final preparation must be maintained. Contents of the reaction vial are intended only for use in the preparation of technetium Tc 99m medronate and are NOT to be administered directly to the patient. Technetium Tc 99m medronate as well as other radioactive drugs, must be handled with care. Once sodium pertechnetate Tc 99m is added to the vial, appropriate safety measures should be used to minimize external radiation to clinical occupational personnel. Care should also be taken to minimize radiation exposure to patients in a manner consistent with proper patient management. To minimize the radiation dose to the bladder, the patient should be encouraged to drink fluids and to void immediately before the examination and as often thereafter as possible for the next four to six hours. Technetium Tc 99m medronate should be formulated within six (6) hours prior to clinical use. Optimal imaging results are obtained one to four hours after administration. Technetium Tc 99m medronate injection should be discarded six hours after reconstitution. The solution should not be used if cloudy. The components of the kit are sterile and pyrogen-free. It is essential to follow directions carefully and to adhere to strict aseptic procedures during preparation. The technetium Tc 99m labeling reactions involved in preparing the agent depend on maintaining the stannous ion in the reduced state. Any oxidant present in the sodium pertechnetate Tc 99m supply may, thus, adversely affect the quality of the radiopharmaceutical. Hence, sodium pertechnetate Tc 99m containing oxidants should not be employed. Radiopharmaceuticals should be used only by physicians who are qualified by training and experience in the safe use and handling of radionuclides. Drug Interactions The biodistribution of technetium Tc 99m medronate may be altered in the presence of high levels of certain cations (iron, calcium, and aluminum). This may result in reduced uptake of radionuclide in the skeleton and increased extraosseal uptake, which may potentially degrade imaging quality. In patients with high levels of these cations caused by concomitant medications, particularly patients receiving iron infusions, consider performing an imaging study with technetium Tc 99m medronate injection once the cation levels have normalized (e.g., after 3 to 5 half-lives of the cation). (See WARNINGS .) Carcinogenesis, Mutagenesis, Impairment of Fertility No long-term animal studies have been performed to evaluate carcinogenic potential or whether technetium Tc 99m medronate affects fertility in males or females. Pregnancy Animal reproduction studies have not been conducted with technetium Tc 99m medronate. It is also not known whether technetium Tc 99m medronate can cause fetal harm when administered to a pregnant woman or can affect reproductive capacity. Technetium Tc 99m medronate should be given to a pregnant woman only if clearly needed. Nursing Mothers Technetium Tc 99m is excreted in human milk during lactation; therefore, formula-feedings should be substituted for breast-feedings. Pediatric Use Safety and effectiveness in children have not been established.

Several adverse reactions due to technetium Tc 99m medronate have been reported. These were usually hypersensitivity reactions characterized by itching, various skin rashes, hypotension, chills, nausea and vomiting. There have also been rare cases of dizziness and asthenia associated with the use of technetium Tc 99m medronate.

The biodistribution of technetium Tc 99m medronate may be altered in the presence of high levels of certain cations (iron, calcium, and aluminum). This may result in reduced uptake of radionuclide in the skeleton and increased extraosseal uptake, which may potentially degrade imaging quality. In patients with high levels of these cations caused by concomitant medications, particularly patients receiving iron infusions, consider performing an imaging study with technetium Tc 99m medronate injection once the cation levels have normalized (e.g., after 3 to 5 half-lives of the cation). (See WARNINGS .)

Animal reproduction studies have not been conducted with technetium Tc 99m medronate. It is also not known whether technetium Tc 99m medronate can cause fetal harm when administered to a pregnant woman or can affect reproductive capacity. Technetium Tc 99m medronate should be given to a pregnant woman only if clearly needed.

Technetium Tc 99m is excreted in human milk during lactation; therefore, formula-feedings should be substituted for breast-feedings.

Safety and effectiveness in children have not been established.