MYOVIEW
Clinical safety rating: caution
Comprehensive clinical and safety monograph for MYOVIEW (MYOVIEW).
Myoview (technetium Tc-99m tetrofosmin) is a lipophilic cationic complex that accumulates in myocardial cells via mitochondrial uptake. It is used as a myocardial perfusion imaging agent to assess regional blood flow.
| Metabolism | Technetium Tc-99m tetrofosmin is not metabolized; it is eliminated primarily via the renal system as unchanged drug. |
| Excretion | Renal: 93% within 24 hours (primarily as unchanged drug); Fecal: 5%; Biliary: negligible |
| Half-life | Terminal elimination half-life: 4.3–6.1 hours (mean 5.2 hours); clinical context: allows imaging up to 6 hours post-injection with stable myocardial retention |
| Protein binding | ~90% bound to serum albumin and globulins |
| Volume of Distribution | Initial Vd: 0.3–0.4 L/kg; Steady-state Vd: 0.5–0.8 L/kg; indicates primarily extracellular distribution with some tissue binding |
| Bioavailability | Intravenous: 100% (only route of administration) |
| Onset of Action | Intravenous: myocardial uptake begins within 1–2 minutes; peak myocardial activity at 5–10 minutes |
| Duration of Action | Myocardial retention sufficient for planar or SPECT imaging for up to 4–6 hours; redistribution minimal; clinical note: imaging should be completed within 2 hours of injection for best results |
0.08 mg/kg intravenous bolus, maximum 9 mg, followed by saline flush. Imaging within 30-60 minutes post-injection.
| Dosage form | INJECTABLE |
| Renal impairment | No dose adjustment required in renal impairment; agent is not significantly renally eliminated. |
| Liver impairment | No specific Child-Pugh based adjustments; use caution in severe hepatic impairment due to potential altered distribution. |
| Pediatric use | 0.08 mg/kg intravenous bolus, maximum 9 mg. Safety and efficacy in children <2 years not established. |
| Geriatric use | No specific adjustment; use standard dose with attention to renal function and hydration status. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for MYOVIEW (MYOVIEW).
| Breastfeeding | It is not known whether technetium Tc-99m tetrofosmin is excreted in human milk. However, many radiopharmaceuticals are excreted in human milk. Because of the potential for radiation exposure to the nursing infant, breastfeeding should be interrupted after administration of Myoview. The European guidelines recommend discontinuing breastfeeding for at least 12 hours after injection; discard expressed milk during this period. M/P ratio is not available. |
| Teratogenic Risk | Animal reproduction studies have not been conducted with this radiopharmaceutical. It is not known whether Myoview (technetium Tc-99m tetrofosmin) can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity. Myoview should be given to a pregnant woman only if clearly needed. Radiopharmaceuticals are known to cross the placenta and accumulate in fetal tissues; radiation exposure to the fetus should be minimized. The risk is highest during the first trimester when organogenesis occurs. |
■ FDA Black Box Warning
None.
| Serious Effects |
["None known absolute contraindications","Relative: Pregnancy and breastfeeding should be considered for risk-benefit assessment"]
| Precautions | ["Risk of hypersensitivity reactions including anaphylaxis","Risk of radiation exposure; use only in clearly indicated situations","Caution in patients with renal impairment as clearance may be reduced","Ensure adequate hydration to minimize radiation dose to bladder"] |
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| Fetal Monitoring | If administration is necessary during pregnancy, document the patient's pregnancy status and ensure the benefit justifies the radiation risk. No specific fetal monitoring is required, but minimize fetal radiation exposure by using the lowest possible dose and ensuring adequate hydration to promote rapid excretion. Post-administration, encourage frequent voiding. |
| Fertility Effects | No studies have been conducted on the effect of Myoview on fertility. Based on the mechanism of action (diagnostic radiopharmaceutical) and lack of known reproductive toxicity, clinically significant effects on fertility are unlikely at diagnostic doses. |