UROCIT-K
Clinical safety rating: caution
Comprehensive clinical and safety monograph for UROCIT-K (UROCIT-K).
Potassium citrate provides alkali (bicarbonate) upon metabolism, increasing urinary citrate and pH. Citrate chelates calcium, reducing calcium oxalate and calcium phosphate supersaturation; it also inhibits crystal aggregation and growth.
| Metabolism | Metabolized in the liver via the tricarboxylic acid cycle to bicarbonate; potassium is excreted renally. |
| Excretion | Primarily renal; >90% of absorbed potassium is excreted unchanged in urine via renal tubular secretion and glomerular filtration. |
| Half-life | Approximately 12-18 hours, reflecting steady-state maintenance with extended-release formulation; clinical significance: twice-daily dosing maintains stable serum potassium. |
| Protein binding | Negligible; potassium is not significantly bound to plasma proteins. |
| Volume of Distribution | Approximately 0.5 L/kg, approximating total body water; indicates distribution primarily in extracellular fluid. |
| Bioavailability | ~90% for potassium chloride from extended-release formulation; absorption complete in small intestine, with some variation due to GI transit time. |
| Onset of Action | Not applicable for rapid onset; therapeutic effect on serum potassium occurs gradually over 2-3 days with consistent dosing. |
| Duration of Action | Twice-daily dosing provides sustained effect over 24 hours with pill-in-shell extended-release matrix; steady state achieved in 3-4 days. |
| Molecular Weight | 306.39 Da (for potassium citrate; actual salt form: C6H5K3O7) |
Initial: 10–20 mEq (2–4 tablets) orally three times daily with meals; titrate to maintain urinary citrate >320 mg/day and pH 6.5–7.2. Maximum dose: 100 mEq/day (20 tablets).
| Dosage form | TABLET, EXTENDED RELEASE |
| Renal impairment | Contraindicated if GFR <30 mL/min or oliguria. For GFR 30–50 mL/min: use with caution and monitor potassium closely; dose reduction typically required, but no specific guidelines; avoid if possible. |
| Liver impairment | No specific Child-Pugh based dose adjustments recommended; use with caution in severe hepatic impairment due to risk of electrolyte disturbances. |
| Pediatric use | Not FDA-approved for children. Dosing based on limited data: 2–3 mEq/kg/day divided into 4 doses (with meals and at bedtime), titrated to achieve urinary citrate of 250–400 mg/g creatinine. |
| Geriatric use | Start at lower end of dosing range (10–20 mEq/day in divided doses); monitor renal function and serum potassium closely due to age-related decline in GFR and increased risk of hyperkalemia. |
| 1st trimester | Urocit-K (potassium citrate) is pregnancy category C. No adequate studies in pregnant women. Use only if clearly needed and potential benefit justifies risk to fetus. |
| 2nd trimester | Same as t1. Although potassium citrate is used to manage conditions like kidney stones and urinary citrate deficiency, there are no well-controlled studies in pregnant women. Avoid use unless essential. |
| 3rd trimester | Same as t1. Monitor maternal potassium levels closely if used near term, as electrolyte imbalances may affect fetal heart rate or uterine contractility. |
Clinical note
Comprehensive clinical and safety monograph for UROCIT-K (UROCIT-K).
| Placental transfer | Potassium freely crosses the placenta; citrate is a normal metabolite. Degree of transfer is likely dose-dependent, but no specific data on potassium citrate-transfer efficiency. Generally, potassium homeostasis is tightly regulated by maternal-fetal exchange. |
| Breastfeeding |
■ FDA Black Box Warning
None
| Serious Effects |
Severe renal impairment (GFR < 30 mL/min/1.73m²) or chronic kidney disease stage 4-5Adrenal insufficiency (risk of hyperkalemia)Acute dehydration, hyperkalemia, or conditions predisposing to hyperkalemia (e.g., untreated Addison's disease)Peptic ulcer disease or active gastrointestinal bleeding (due to citrate irritation)Severe metabolic alkalosis (citrate is alkalinizing)
| Precautions | Hyperkalemia risk, especially in patients with renal impairment, diabetes, or concurrent use of potassium-sparing diuretics, ACE inhibitors, or ARBs, Gastrointestinal adverse effects: ulceration, bleeding, perforation (slow-release formulation may reduce risk), Use with caution in patients with cardiac disease or conditions predisposing to hyperkalemia, Monitor serum potassium, bicarbonate, and renal function periodically, Dose adjustment required in renal insufficiency |
| Food/Dietary | Avoid excessive intake of high-potassium foods (e.g., bananas, oranges, potatoes, spinach, avocados, salt substitutes). Do not take with high-sodium foods that may reduce citrate effect. Take with food to minimize gastrointestinal irritation. |
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| Potassium citrate is excreted into breast milk in small amounts. In normal maternal doses, it is generally considered compatible with breastfeeding. However, caution is advised with high doses or in mothers with renal impairment to avoid hyperkalemia in the infant. Monitor infant for signs of hyperkalemia (e.g., weakness, cardiac arrhythmias). |
| Lactation Rating | L2 (Probably Compatible) |
| Teratogenic Risk | FDA Pregnancy Category C. No adequate studies in pregnant women. Potassium citrate is not known to be teratogenic in animal studies at doses up to 50 times the human dose; however, fetal harm cannot be ruled out. During first trimester, risk is theoretical due to lack of human data. In second and third trimesters, use only if clearly needed as hypokalemia may cause maternal complications affecting fetus. |
| Fetal Monitoring | Monitor serum potassium levels regularly (e.g., monthly, more frequently if renal impairment). Assess renal function via serum creatinine and urine output. Monitor for signs of hyperkalemia (ECG changes, muscle weakness) especially in preeclampsia or renal disease. Fetal monitoring as per standard obstetric care. |
| Fertility Effects | No known impairment of fertility in animal studies. Human data lacking. Potassium citrate may correct hypokalemia-related infertility, but no direct evidence of harm. |
| Clinical Pearls | UROCIT-K (potassium citrate) is used for hypocitraturia, distal renal tubular acidosis, and uric acid stones. Monitor serum potassium and renal function; avoid in severe renal impairment or hyperkalemia. Wax matrix formulation may cause GI injury; instruct to swallow whole, not crush or chew. |
| Patient Advice | Take with food and a full glass of water to reduce GI irritation. · Do not crush, chew, or break the tablet; swallow whole. · Avoid high-potassium foods (e.g., bananas, oranges, salt substitutes) unless directed. · Report muscle weakness, palpitations, or tingling (signs of hyperkalemia). · Keep tablets in original container; protect from moisture. |