UREAPHIL
Clinical safety rating: safe
No significant drug interactions For topical use only can cause mild irritation.
Ureaphil (urea) acts as an osmotic diuretic by increasing plasma osmolarity, thereby drawing water from tissues into the bloodstream and enhancing renal water excretion. It also reduces intracranial and intraocular pressure by osmotic effects.
| Metabolism | Urea is metabolized in the gastrointestinal tract by bacterial urease to ammonia, which is then converted to urea in the liver via the urea cycle. Systemically administered urea is not significantly metabolized; it is largely excreted unchanged by the kidneys. |
| Excretion | Renal: >95% unchanged via glomerular filtration and tubular secretion; biliary/fecal: <5%. |
| Half-life | Terminal elimination half-life is 15-20 hours; clinically, steady-state is reached within 3-4 days. |
| Protein binding | Approximately 70% bound to albumin. |
| Volume of Distribution | 0.3-0.5 L/kg; indicates distribution primarily in extracellular fluid. |
| Bioavailability | Oral: 80-90% due to moderate first-pass metabolism. |
| Onset of Action | Oral: 30-60 minutes; IV: immediate (within minutes). |
| Duration of Action | 8-12 hours with single dose; sustained with chronic dosing due to accumulation. |
30-60 mg orally once daily
| Dosage form | INJECTABLE |
| Renal impairment | eGFR 30-89 mL/min: no adjustment; eGFR <30 mL/min: contraindicated |
| Liver impairment | Child-Pugh A: 30 mg daily; Child-Pugh B or C: contraindicated |
| Pediatric use | 0.5-1 mg/kg orally once daily; maximum 60 mg |
| Geriatric use | Start 30 mg daily; monitor renal function due to age-related decline |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
No significant drug interactions For topical use only can cause mild irritation.
| FDA category | Animal |
| Breastfeeding | Urea is a normal constituent of milk. Exogenous urea is excreted into breast milk, but concentrations are low and no adverse effects are expected. M/P ratio not reported. Considered compatible with breastfeeding. |
| Teratogenic Risk | Urea use in pregnancy has not been associated with increased risk of major congenital malformations. However, data are limited. First trimester exposure: insufficient human data; animal studies show no teratogenicity at therapeutic doses. Second/third trimester: used as a tocolytic agent for preterm labor, no evidence of fetal harm from short-term use. High doses may cause maternal hypernatremia and fetal fluid shifts. |
■ FDA Black Box Warning
None
| Common Effects | xerosis |
| Serious Effects |
["Anuria or severe renal impairment","Active intracranial bleeding","Severe dehydration","Hypersensitivity to urea or any component of the formulation"]
| Precautions | ["Risk of severe dehydration and electrolyte imbalances (e.g., hyponatremia, hypokalemia)","May cause intravascular volume expansion leading to pulmonary edema or heart failure in patients with cardiac disease","Extravasation may cause tissue necrosis","Rapid administration may cause hemolysis","Monitor serum electrolytes, BUN, creatinine, and fluid balance during therapy","Use with caution in patients with renal impairment, hepatic disease, or adrenal insufficiency"] |
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| Fetal Monitoring | Monitor maternal serum electrolytes, osmolality, and fluid balance during intravenous administration. Assess for signs of hypernatremia, dehydration, or volume overload. Fetal heart rate monitoring during labor if used for tocolysis. |
| Fertility Effects | No known adverse effects on fertility. Urea is a naturally occurring substance and does not impact reproductive function in animal studies. |