Myoview Dosage

Radiation Safety – Drug Handling

Technetium Tc99m tetrofosmin is a radioactive drug and should be handled with appropriate safety measures to minimize radiation exposure during administration [see Warnings and Precautions (5.2)]. Use waterproof gloves and effective shielding, including syringe shields, when preparing and administering technetium Tc99m tetrofosmin injection.

Recommended Dosage

• The recommended dose range for MYOVIEW is 185 to 1,221 MBq (5 to 33 mCi) by intravenous administration for rest and stress imaging.
• When rest and stress intravenous injections are administered on the same day, the first dose should be 185 to 444 MBq (5 to 12 mCi) and followed by the second dose of 555 to 1,221 MBq (15 to 33 mCi) given approximately 1 to 4 hours later.
• The recommended dose range for MYOVIEW is 185 to 1,221 MBq (5 to 33 mCi) by intravenous administration as an intravenous injection for ventricular function assessment.

Administration Instructions

• Use aseptic technique for all drug preparation and handling.
• Measure the dose in a suitable radioactivity calibration system immediately prior to intravenous administration.
• Visually inspect the drug for particulate matter and discoloration prior to administration. Do not use or administer the drug if there is evidence of particulate matter or discoloration.
• Instruct patients to remain hydrated and void frequently following administration to decrease radiation exposure [see Warnings and Precautions (5.2)].

Instructions for Preparation

1. The technetium Tc99m labeling reaction involved in the preparation of MYOVIEW Injection depends on maintaining tin in the divalent (reduced) state. Any oxidant present in the sodium pertechnetate Tc99m used may adversely affect the quality of the preparation. Sodium pertechnetate Tc99m containing oxidants should not be used for the preparation of the labeled product.
2. Elute the technetium generator with sodium chloride injection, USP.
3. Insert a venting needle (standard 18 to 26 gauge needle, not provided) through the rubber septum of the shielded vial containing the lyophilized powder.
4. Inject no more than 89 GBq (2.4 Ci) of technetium Tc99m generator eluate into the shielded vial.
5. Use sodium chloride injection, USP as a diluent. Inject 10 to 30 mL to achieve a radioactive concentration no greater than 2.96 GBq/mL (80 mCi/mL) in the vial.
6. If a venting needle is not used, before removing the syringe from the vial, withdraw an adequate volume of gas from above the solution to avoid over-pressurizing the vial.
7. Remove the venting needle.
8. Mix gently for 10 seconds to ensure complete dissolution of the powder.
9. Incubate at room temperature for 15 minutes.
10. Assay the total activity using a suitably calibrated instrument; complete the user radiation label and attach it to the vial.
11. Measure the pH of the prepared injection and verify it is between 7.5 to 9.0.
12. Store the radiolabeled MYOVIEW 30 mL vial and withdrawals for injection at 2° to 25°C (36° to 77°F) and use within 12 hours of preparation.

Determination of Radiochemical Purity

Imaging Instructions

• Imaging may begin 15 minutes after injection.
• The recommended imaging duration of the scan may vary depending on dose, imaging acquisition, and reconstruction parameters.

Radiation Dosimetry

Radiation absorbed dose per unit activity of the agent injected intravenously in an adult of average weight (74 kg) is estimated in Table 1 for exercise and resting conditions. The values listed correspond to a 3.5-hour voiding period for excretion from the urinary bladder.