PHOSLYRA
Clinical safety rating: caution
Comprehensive clinical and safety monograph for PHOSLYRA (PHOSLYRA).
Phoslyra (calcium acetate) binds dietary phosphate in the gastrointestinal tract, forming insoluble calcium phosphate complexes that are excreted in the feces, thereby reducing serum phosphate levels.
| Metabolism | Calcium acetate is not metabolized; it dissociates to release calcium ions which are partially absorbed, but the majority of the calcium-phosphate complex is excreted in feces. |
| Excretion | Renal 100% as unchanged drug, no biliary or fecal elimination. |
| Half-life | Not applicable; Phoslyra (calcium acetate) is not absorbed systemically; local effect in GI tract. |
| Protein binding | Not applicable (no systemic absorption). |
| Volume of Distribution | Not applicable (no systemic absorption). |
| Bioavailability | Oral bioavailability is negligible (<0.1%); acts locally. |
| Onset of Action | Immediately upon oral administration; binds dietary phosphate in GI tract. |
| Duration of Action | Duration equals GI transit time (~3-4 hours); requires administration with each meal. |
1330 mg (one caplet) orally three times daily with meals, titrated to achieve serum phosphorus within target range.
| Dosage form | SOLUTION |
| Renal impairment | No dose adjustment required for GFR 15-59 mL/min. For GFR <15 mL/min or dialysis, starting dose 1330 mg three times daily with meals, titrate per serum phosphorus. |
| Liver impairment | No specific adjustments for hepatic impairment; use with caution in severe impairment. |
| Pediatric use | Not established for children under 18 years; safety and efficacy not determined. |
| Geriatric use | No specific geriatric dose adjustment; monitor renal function and serum calcium/phosphorus. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for PHOSLYRA (PHOSLYRA).
| Breastfeeding | Calcium acetate is excreted into human milk; however, the amount is unlikely to affect the nursing infant. M/P ratio not established. Use with caution, monitoring infant for signs of hypercalcemia. |
| Teratogenic Risk | Phoslyra (calcium acetate) is a phosphate binder. No teratogenic effects have been reported in animal studies; however, there are no adequate and well-controlled studies in pregnant women. Hypercalcemia during pregnancy may lead to adverse fetal effects including hypotonia, seizures, and cardiac abnormalities. Risk is dose-dependent. |
■ FDA Black Box Warning
None
| Serious Effects |
Hypercalcemia, hypophosphatemia, or hypersensitivity to any component.
| Precautions | Hypercalcemia may occur; monitor serum calcium levels regularly. Avoid use with vitamin D analogs unless calcium levels are monitored. Use with caution in patients with arrhythmias, renal stones, or sarcoidosis. Ensure adequate hydration to prevent constipation. |
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| Fetal Monitoring |
| Maternal serum calcium and phosphate levels should be monitored regularly. Fetal monitoring may include ultrasound for signs of hypercalcemia-related effects, though specific guidelines are not established. |
| Fertility Effects | No known effects on fertility. Calcium acetate does not directly impair reproductive function, but underlying renal disease may affect fertility. |