Indications for: FOSRENOL

To reduce serum phosphate in end-stage renal disease.

Adult Dosage:

Take with meals. Chew or crush tabs completely before swallowing. Poor dentition or difficulty chewing tabs: consider using oral pwd form. Oral pwd: sprinkle on small quantity of applesauce or similar food and consume immediately; do not dissolve pwd in liquid for administration. Initially 1.5g/day in divided doses. Titrate at 2–3 wk intervals in increments of 750mg/day based on serum phosphate. Usual range: 1.5g–3g.

Children Dosage:

Not recommended.

FOSRENOL Contraindications:

Bowel obstruction, including ileus and fecal impaction.

FOSRENOL Warnings/Precautions:

Chew tabs: risk of severe GI obstruction/perforation esp. in abnormal GI anatomy (eg, diverticular disease, peritonitis, history of GI surgery, cancer, ulceration) and hypomotility disorders (eg, constipation, ileus, subileus, diabetic gastroparesis). Monitor for GI disorders; reevaluate if severe constipation or other GI signs/symptoms develop. Do not swallow whole; serious GI complications with unchewed or incompletely chewed tabs. Acute peptic ulcer. Ulcerative colitis. Crohn's disease. Monitor serum phosphate levels. Pregnancy. Nursing mothers.

FOSRENOL Classification:

Phosphate binder.

FOSRENOL Interactions:

Separate dosing of drugs that interact with antacids by 2hrs. Antagonizes quinolone antibiotics; give quinolone 1hr before or 4hrs after Fosrenol. If quinolone given for short course, consider eliminating Fosrenol doses scheduled near quinolone intake to improve quinolone absorption. Antagonizes levothyroxine; separate administration by 2hrs, monitor TSH levels. Risk of GI obstruction or perforation with concomitant medications known to potentiate GI effects. Consider monitoring concomitant drugs that have a narrow therapeutic range. May interfere with abdominal x-ray.

Adverse Reactions:

Nausea, vomiting, abdominal pain; serious GI effects.

Drug Elimination:

  • Fecal (94–99%), renal (<2%). Biliary excretion is the predominant route of elimination.

Generic Drug Availability:


How Supplied:

Tabs 500mg patient pack (2 x 45 tabs)—1; Tabs 750mg patient pack (6 x 15 tabs)—1; Tabs 1000mg patient pack (9 x 10 tabs)—1; Oral pwd stick pack—10; Oral pwd patient pack (9 x 10 stick packs)—1