XENON XE 127
Clinical safety rating: caution
Comprehensive clinical and safety monograph for XENON XE 127 (XENON XE 127).
Xenon Xe 127 is a radioactive isotope that emits gamma radiation and is used as a diagnostic imaging agent. Its mechanism is based on the physical properties of radioactive decay, allowing for scintigraphic imaging of pulmonary ventilation and cerebral blood flow.
| Metabolism | Not metabolized; eliminated via exhalation unchanged. |
| Excretion | Primarily eliminated via exhalation as unchanged gas (>95%). Minimal renal excretion of dissolved xenon (<5%). No biliary or fecal elimination due to inert nature. |
| Half-life | Terminal elimination half-life is approximately 5 minutes for the washout phase from well-perfused tissues. In poorly perfused fat, a slower phase with half-life of ~30 minutes may occur. Clinically, the gas is rapidly cleared from the body upon cessation of administration. |
| Protein binding | Negligible protein binding (<1%). Xenon is inert and does not bind significantly to plasma proteins. |
| Volume of Distribution | Volume of distribution is approximately 3-5 L/kg, reflecting extensive distribution to tissues including fat, due to high lipid solubility. |
| Bioavailability | Inhalation: Bioavailability is 100% due to direct delivery to pulmonary circulation. No other routes are clinically relevant. |
| Onset of Action | Inhalation: Onset of clinical effect (anesthesia) occurs within 1-2 minutes at inspired concentrations of 70-80%. |
| Duration of Action | Duration of anesthesia is short, lasting 2-5 minutes after discontinuation of inhalation due to rapid washout. Recovery is prompt, with orientation typically returning within 1-3 minutes. |
| Molecular Weight | 126.904 |
5-10 mCi (185-370 MBq) inhaled as a single dose for pulmonary ventilation studies.
| Dosage form | GAS |
| Renal impairment | No adjustment required as Xenon Xe 127 is eliminated via exhalation. |
| Liver impairment | No adjustment required as Xenon Xe 127 is not hepatically metabolized. |
| Pediatric use | 0.1-0.2 mCi/kg (3.7-7.4 MBq/kg) inhaled, maximum 10 mCi. |
| Geriatric use | No specific adjustment; use standard adult dose with caution due to potential reduced pulmonary function. |
| 1st trimester | Avoid; radioactive xenon crosses placenta; risk of fetal radiation exposure with potential teratogenicity. |
| 2nd trimester | Avoid; risk of fetal radiation exposure; use only if benefit justifies risk. |
| 3rd trimester | Avoid; risk of fetal radiation exposure; near delivery, consider cumulative dose to fetus. |
Clinical note
Comprehensive clinical and safety monograph for XENON XE 127 (XENON XE 127).
| Placental transfer | Yes; xenon, being a noble gas, readily crosses the placenta; fetal exposure documented. |
| Breastfeeding | Radioactive xenon excreted in breast milk; potential for infant radiation exposure. Discontinue breastfeeding or hold for at least 5 half-lives (approx. 5 x 36.4 days = 182 days) after administration. |
| Lactation Rating |
■ FDA Black Box Warning
None.
| Serious Effects |
PregnancyBreastfeedingKnown hypersensitivity to xenon
| Precautions | Radiation exposure risk; use only when necessary in pregnant women and children., Ensure proper handling and disposal to minimize exposure to personnel and environment. |
| Food/Dietary | No specific food interactions. However, patients should avoid heavy meals immediately before the study to prevent aspiration or discomfort during inhalation. No dietary restrictions otherwise. |
| Clinical Pearls |
Loading safety data…
| Avoid |
| Teratogenic Risk | Xenon Xe 127 is a radioactive gas. Exposure during pregnancy poses a risk of fetal radiation exposure. First trimester: highest risk for teratogenicity (e.g., CNS malformations, growth restriction). Second trimester: risk of growth restriction and neurodevelopmental effects. Third trimester: risk of childhood cancer and growth restriction. Consider alternative imaging modalities. |
| Fetal Monitoring | Monitor maternal vital signs during administration, fetal heart rate if indicated, and cumulative radiation exposure. Post-administration, monitor for signs of radiation side effects. Long-term pediatric follow-up for potential radiation-induced effects. |
| Fertility Effects | Possible gonadal radiation exposure may reduce fertility. Fertility effects depend on absorbed dose; transient or permanent impairment possible. Discuss with patient prior to exposure. |
| Xenon Xe 127 is a radioactive gas used in pulmonary ventilation studies. It is administered via inhalation. Key pearls: (1) Ensure patient does not smoke or use nicotine products for at least 6 hours prior to study to reduce background activity. (2) Scintigraphy must be performed promptly after inhalation due to short half-life (36.4 days). (3) Contamination risk is low but proper ventilation and waste disposal are critical. (4) Contraindicated in severe COPD or respiratory distress due to inability to hold breath. |
| Patient Advice | This is a radioactive gas used to image lung ventilation. · You will inhale the gas through a mouthpiece or mask; no pain is involved. · The radiation exposure is low and similar to a chest X-ray. · Avoid smoking or using nicotine for 6 hours before the test. · Inform your doctor if you are pregnant or breastfeeding. · You may be asked to hold your breath for 10-20 seconds. · After the test, you can resume normal activities immediately. |