MACROTEC
Clinical safety rating: caution
Comprehensive clinical and safety monograph for MACROTEC (MACROTEC).
Not applicable for diagnostic use.
| Metabolism | Not metabolized; particles are cleared by the reticuloendothelial system. |
| Excretion | Renal: 95% as unchanged drug; biliary/fecal: <5% as metabolites |
| Half-life | 6 hours; prolonged in renal impairment (up to 30 hours in ESRD) |
| Protein binding | 10-20% bound to albumin |
| Volume of Distribution | 0.3-0.5 L/kg; reflects distribution into extracellular fluid |
| Bioavailability | IV: 100%; oral: 50-70% due to first-pass metabolism |
| Onset of Action | IV: immediate; oral: 30 minutes to 1 hour |
| Duration of Action | 6-8 hours for radiolabeling; clinical effect may persist up to 12 hours |
5 mCi (185 MBq) intravenously as a single dose for lung perfusion imaging.
| Dosage form | INJECTABLE |
| Renal impairment | No dose adjustment required; MACROTEC is not significantly cleared renally. |
| Liver impairment | No dose adjustment required; MACROTEC undergoes minimal hepatic metabolism. |
| Pediatric use | 0.03 mCi/kg (1.1 MBq/kg) intravenously, minimum 0.3 mCi (11.1 MBq). |
| Geriatric use | No specific dose adjustment; use with caution due to potential underlying cardiopulmonary disease. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for MACROTEC (MACROTEC).
| Breastfeeding | Technetium Tc 99m is excreted into breast milk. The amount is small; the M/P ratio is not established. However, to minimize infant radiation exposure, breastfeeding should be interrupted for at least 4-6 hours after administration. Some guidelines recommend pumping and discarding milk for 24 hours. |
| Teratogenic Risk | MACROTEC (technetium Tc 99m aggregated albumin) is a radiopharmaceutical. Fetal radiation exposure is dose-dependent; at typical diagnostic doses (<5 mSv), teratogenic risk is low. However, any radiation carries a small stochastic risk, especially during organogenesis (weeks 2-8). The benefit of the diagnostic procedure must outweigh the risk. Avoid use in pregnancy unless absolutely necessary. |
■ FDA Black Box Warning
None.
| Serious Effects |
["Known hypersensitivity to technetium-99m or albumin","Severe pulmonary hypertension"]
| Precautions | ["Risk of allergic reactions","Caution in patients with pulmonary hypertension","Caution in patients with severe right-to-left shunts"] |
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| Fetal Monitoring | Maternal monitoring includes assessment for allergic reactions, particularly in patients with known hypersensitivity to albumin or prior reaction to radiopharmaceuticals. Fetal monitoring is not typically performed, but if inadvertent high-dose exposure occurs, consider fetal dosimetry and counseling. |
| Fertility Effects | At diagnostic doses, no known adverse effects on fertility. No human studies; animal studies show no impairment at relevant doses. |