CYSTOGRAFIN DILUTE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for CYSTOGRAFIN DILUTE (CYSTOGRAFIN DILUTE).
Cystografin dilute is a radiocontrast agent containing diatrizoate meglumine, which is an ionic monomeric iodinated compound. It provides radiopacity by absorbing X-rays due to the high atomic number of iodine, allowing visualization of the urinary tract during retrograde cystourethrography. The mechanism is purely physical, with no pharmacological effect.
| Metabolism | Diatrizoate is not metabolized; it is excreted unchanged by glomerular filtration with minimal tubular reabsorption. |
| Excretion | Renal: >95% unchanged via glomerular filtration; biliary/fecal: <5% |
| Half-life | Terminal elimination half-life: 1–2 hours in normal renal function; prolonged in renal impairment (up to 20–30 hours in severe renal failure) |
| Protein binding | Negligible (<1%, primarily to albumin) |
| Volume of Distribution | 0.15–0.3 L/kg (confined to extracellular fluid space) |
| Bioavailability | Oral: <1% (not absorbed); Intravesical: negligible systemic absorption unless mucosal injury; Intravenous: 100%; Intrathecal: 100% at site |
| Onset of Action | Oral: N/A (not absorbed); Intravesical: immediate upon instillation; Intravenous: immediate distribution; Intrathecal: immediate |
| Duration of Action | Intravesical: duration of radiologic procedure (typically 30–60 minutes); Intravenous: imaging window of 60–90 minutes |
Instill 200-300 mL of CYSTOGRAFIN DILUTE (17.2% iodine) via bladder catheter for retrograde cystography. For intraoperative cholangiography, instill 10-25 mL via cystic duct catheter. For voiding cystourethrography (VCUG), fill bladder to capacity (typically 300-500 mL in adults) under gravity until voiding occurs.
| Dosage form | SOLUTION |
| Renal impairment | No dose adjustment required as the drug is administered locally and not systemically absorbed. Use caution in patients with severe renal impairment (eGFR <30 mL/min/1.73 m²) due to potential for systemic absorption through disrupted mucosa; consider alternative imaging if possible. |
| Liver impairment | No specific dose adjustment needed. Not significantly metabolized by the liver. Use standard dosing regardless of Child-Pugh class. |
| Pediatric use | VCUG: Age-based bladder filling: <1 year: 30-60 mL; 1-4 years: 60-120 mL; 4-8 years: 120-180 mL; 8-12 years: 180-240 mL; >12 years: adult volumes (300-500 mL). For neonates, use lower concentrations (e.g., 17.2% or less) and fill until resistance or voiding. Do not exceed 20 mL/kg instillation volume. |
| Geriatric use | No specific dose adjustment. Use the same adult dosing. Monitor for bladder overdistension and consider reduced bladder capacity in elderly patients. Use smaller instill volumes (150-250 mL) if bladder compliance is decreased. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for CYSTOGRAFIN DILUTE (CYSTOGRAFIN DILUTE).
| Breastfeeding | Limited data: Diatrizoate is excreted into human breast milk in small amounts. The M/P ratio is unknown. The American College of Radiology recommends that breastfeeding may be continued without interruption after receiving iodinated contrast because the amount absorbed by the infant is negligible (<1% of administered dose). However, some sources suggest discarding milk for 24 hours. Discuss with mother. |
| Teratogenic Risk | Cystografin Dilute (diatrizoate meglumine) is an iodinated radiocontrast agent. There are no adequate and well-controlled studies in pregnant women. Iodinated contrast agents cross the placenta. Fetal exposure in utero may cause transient neonatal hypothyroidism. Risk is highest during the second and third trimesters when the fetal thyroid is functional. Animal studies have not shown teratogenic effects. Use only if clearly needed and potential benefit justifies risk. |
■ FDA Black Box Warning
Not applicable. Cystografin dilute does not carry an FDA black box warning.
| Serious Effects |
["Known hypersensitivity to diatrizoate or any component of the formulation","Anuria or severely impaired renal function (when systemic absorption is expected, as in intravenous use; for intravesical use, contraindicated only if bladder rupture or systemic absorption is likely)","Concurrent administration with oral cholecystographic agents"]
| Precautions | ["Severe hypersensitivity reactions, including anaphylaxis, may occur, especially in patients with history of allergy, asthma, or prior contrast reaction.","Acute kidney injury may occur, particularly in patients with pre-existing renal impairment, diabetes mellitus, or dehydration.","Extravasation can cause local tissue injury, requiring prompt management.","Use with caution in patients with heart failure, severe hypertension, or pheochromocytoma.","Thyroid storm risk in patients with hyperthyroidism or thyroid nodules."] |
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| Fetal Monitoring | Monitor maternal vital signs and for hypersensitivity reactions during administration. Thyroid function (TSH) in the neonate should be checked within the first week of life if the agent was used during pregnancy, especially after the first trimester. Assess for signs of hypothyroidism. |
| Fertility Effects | No known adverse effects on fertility in animal studies. Human data are lacking. Iodinated contrast agents are not known to impair fertility. |