NULYTELY
Clinical safety rating: caution
Comprehensive clinical and safety monograph for NULYTELY (NULYTELY).
Polyethylene glycol (PEG) 3350 is an osmotic agent that induces diarrhea by drawing water into the gastrointestinal tract, thereby cleansing the bowel. Sodium sulfate and electrolytes (sodium, potassium, bicarbonate) are added to prevent fluid and electrolyte shifts.
| Metabolism | PEG 3350 is not metabolized; it is excreted unchanged in feces. Electrolytes are absorbed and excreted via renal pathways as needed. |
| Excretion | NULYTELY (polyethylene glycol 3350) is minimally absorbed systemically (<0.06%). The primary route of elimination is fecal excretion of the intact polymer. Renal excretion is negligible (<0.02%). |
| Half-life | Not applicable; NULYTELY is not systemically absorbed in significant amounts, so a terminal elimination half-life is not defined. The drug acts locally in the gastrointestinal tract. |
| Protein binding | Minimal to none, as the drug is not absorbed. If trace amounts enter circulation, protein binding is negligible. |
| Volume of Distribution | Not applicable; due to negligible systemic absorption, a meaningful volume of distribution cannot be determined. The drug remains within the gastrointestinal lumen. |
| Bioavailability | Oral: <0.06% (negligible systemic absorption). Bioavailability is essentially zero. |
| Onset of Action | Oral: Onset of bowel activity typically occurs within 30-60 minutes of administration, with a bowel movement occurring within 1-2 hours. |
| Duration of Action | The effect lasts for the duration of the dosing regimen (usually 3-4 hours for bowel preparation). Prolonged effects beyond 6 hours are uncommon. |
4 liters orally of the reconstituted solution as a single dose for colonoscopy preparation, typically administered in divided doses (e.g., 240 mL every 10 minutes) until rectal effluent is clear. Alternatively, a split-dose regimen: half the solution evening before, half on the day of procedure.
| Dosage form | FOR SOLUTION |
| Renal impairment | Caution in severe renal impairment (eGFR <30 mL/min/1.73m²): monitor for fluid and electrolyte imbalances; consider alternative agents. No specific dose adjustment defined; use with close monitoring. |
| Liver impairment | No specific Child-Pugh based modifications. Use with caution in patients with ascites due to risk of fluid overload and electrolyte abnormalities. |
| Pediatric use | Weight-based dosing for colonoscopy preparation: 25-40 mL/kg orally, up to 4 L total. Administer in divided doses as per adult schedule. Safety and efficacy not established in children <6 months. |
| Geriatric use | No specific dose adjustment; however, elderly patients are at increased risk for adverse effects (e.g., aspiration, fluid/electrolyte disturbances, cardiac arrhythmias). Ensure adequate hydration and monitoring of electrolytes during and after administration. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for NULYTELY (NULYTELY).
| Breastfeeding | PEG 3350 is minimally absorbed systemically (<0.06%) and is not expected to pass into breast milk in significant amounts. The M/P ratio is not established due to negligible plasma levels. It is considered compatible with breastfeeding by the American Academy of Pediatrics. |
| Teratogenic Risk | PEG 3350 and electrolytes are considered low risk for teratogenicity. No increased risk of major birth defects has been observed in animal studies or human case reports. However, the risk of maternal dehydration or electrolyte imbalance could indirectly affect fetal well-being, especially if used improperly. The drug is generally avoided in pregnancy unless clearly needed. |
■ FDA Black Box Warning
There is no FDA black box warning for NULYTELY.
| Serious Effects |
["Gastrointestinal obstruction","Gastric retention","Bowel perforation","Toxic colitis or toxic megacolon","Ileus"]
| Precautions | ["Risk of serious fluid and electrolyte disturbances (e.g., hyponatremia, hypokalemia, seizures) in patients with renal impairment, heart failure, or those taking diuretics or ACE inhibitors.","Risk of aspiration in patients with impaired gag reflex or altered mental status.","Potential for cardiac arrhythmias due to electrolyte shifts.","Risk of mucosal ulcerations or colitis in patients with inflammatory bowel disease."] |
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| Fetal Monitoring | Monitor maternal hydration status and serum electrolytes (sodium, potassium, chloride) before and after bowel preparation, especially if prolonged or excessive vomiting occurs. Fetal monitoring is not typically required unless maternal condition warrants. |
| Fertility Effects | No known effects on fertility. Animal studies have not shown impairment of fertility or reproductive performance. |