FLUDEOXYGLUCOSE F18
Clinical safety rating: caution
Comprehensive clinical and safety monograph for FLUDEOXYGLUCOSE F18 (FLUDEOXYGLUCOSE F18).
Fludeoxyglucose F18 is a glucose analog that is taken up by cells via glucose transporters (GLUT), particularly GLUT-1. It is phosphorylated to FDG-6-phosphate by hexokinase, which cannot be further metabolized, leading to intracellular accumulation proportional to glucose metabolism. It emits positrons detected by PET imaging.
| Metabolism | Fludeoxyglucose F18 is phosphorylated by hexokinase to FDG-6-phosphate, which is not a substrate for further metabolism or efflux. It does not undergo significant hepatic metabolism. |
| Excretion | Primarily renal; approximately 90% of injected activity is excreted unchanged in urine within the first 2 hours post-injection. Less than 5% is eliminated via feces. |
| Half-life | Terminal elimination half-life is approximately 110 minutes (range 100–120 minutes). This reflects clearance of unmetabolized FDG from plasma and is clinically relevant for imaging timing, as optimal image acquisition occurs 30–60 minutes post-injection to allow for target-to-background ratio maximization. |
| Protein binding | Approximately 0% bound to plasma proteins; fludeoxyglucose F18 is a small polar molecule that is not significantly bound to serum proteins. |
| Volume of Distribution | Volume of distribution (Vd) is approximately 0.3–0.4 L/kg, reflecting distribution primarily into extracellular fluid spaces with preferential uptake in brain, myocardium, and tumor tissues via glucose transporters. |
| Bioavailability | Not applicable for oral route; administered only intravenously. Bioavailability is 100% following IV injection. |
| Onset of Action | Onset of action is not applicable as fludeoxyglucose F18 is a diagnostic radiopharmaceutical; clinical effect (uptake in metabolically active tissues) occurs within minutes after intravenous injection, with peak accumulation in brain and tumors typically achieved by 30–45 minutes. |
| Duration of Action | Duration of action is not applicable; radiotracer accumulation is visualized by PET imaging performed 30–60 minutes post-injection. The effective imaging window is limited by physical decay of F18 (half-life 109.7 minutes) and biological clearance, with adequate count rates up to about 4–6 hours post-injection. |
5-10 mCi (185-370 MBq) intravenous injection, single dose for PET imaging.
| Dosage form | INJECTABLE |
| Renal impairment | No dose adjustment required; drug is a radiopharmaceutical with minimal renal clearance. |
| Liver impairment | No dose adjustment required; drug is a radiopharmaceutical not significantly metabolized by liver. |
| Pediatric use | 0.14 mCi/kg (5.18 MBq/kg) intravenous injection, minimum dose 1 mCi (37 MBq), maximum dose 10 mCi (370 MBq). |
| Geriatric use | No specific dose adjustment; same as adult dosing due to lack of age-related pharmacokinetic changes. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for FLUDEOXYGLUCOSE F18 (FLUDEOXYGLUCOSE F18).
| Breastfeeding | Breastfeeding should be interrupted after Fludeoxyglucose F18 administration. The M/P ratio is not established. Radiation dose to the infant via breast milk is estimated to be low but not negligible. European Association of Nuclear Medicine recommends interrupting breastfeeding for 12 hours post-injection and discarding expressed milk. Alternatively, pumping and discarding milk for 24 hours is advised. The long physical half-life (110 minutes) reduces activity rapidly. |
| Teratogenic Risk | Fluorine-18 emits positrons with consequent gamma radiation. All radiopharmaceuticals, including Fludeoxyglucose F18, carry potential risks to the fetus depending on gestational stage and absorbed dose. First trimester: highest risk of teratogenesis; use only if clearly needed and benefit justifies potential fetal radiation exposure. Second and third trimesters: lower but non-zero risk; radiation exposure should be minimized per ALARA principle. Fetal thyroid uptake of free fluoride may occur. No specific human data on teratogenicity. |
■ FDA Black Box Warning
None.
| Serious Effects |
None known.
| Precautions | ["Risk of false-positive results due to inflammatory or infectious processes","False-negative results in patients with low metabolic activity tumors or hyperglycemia","Risk of adverse reactions including allergic reactions","Pregnancy and lactation considerations","Radiopharmaceutical handling and radiation exposure precautions"] |
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| Fetal Monitoring | No specific monitoring required for the fetus. Administer only if diagnostic benefit outweighs risk. Minimize fetal radiation dose by using the lowest effective activity, ensuring adequate maternal hydration to promote voiding, and instructing the patient to empty bladder frequently. Follow local radiation safety protocols for pregnant patients. |
| Fertility Effects | Administration of Fludeoxyglucose F18 results in radiation exposure to gonads. The radiation dose to ovaries is approximately 0.0022 mGy/MBq (adult female). While such doses are below thresholds for acute effects on fertility, cumulative exposure from repeated examinations should be considered. No direct evidence of impaired fertility from single diagnostic administration. |