Phosphate binders (Aluminum hydroxide / Lanthanum / Sevelamer)

What is this medication for?

• Hyperphosphatemia of CKD when dietary restriction alone fails

How is it given?

Give exactly as your veterinarian prescribed — never change the dose or stop on your own unless your veterinarian has told you to.

What if I miss a dose?

• Give it as soon as you remember — unless it is almost time for the next dose (then skip the missed one; never double up).
• Call your clinic if you miss more than one dose in a row.

Side effects — what should I watch for?

Effects listed as common in this handout

• Constipation (Aluminum's main effect)
• Vomiting/nausea/inappetence (Lanthanum)
• Fat-soluble vitamin depletion (esp. K → coagulation) (Sevelamer)
• Electrolyte shifts (bicarbonate w/ sevelamer HCl) (Possible)

Worth a phone call to your veterinarian

• Aluminum toxicity (chronic CKD use: encephalopathy, osteomalacia, myopathy) (The reason for alternatives)

⚠️ Contact your veterinarian or an emergency clinic IMMEDIATELY if you notice

• Trouble breathing, collapse, seizures, severe vomiting or diarrhea, facial swelling, or pale gums

Before starting (or refilling), tell your veterinarian if your pet:

• has or has had: Gastric outlet obstruction (aluminum antacids inhibit emptying); hypophosphatemia from over-bounding; stomach/intestinal obstruction strictures (sevelamer human warning)

• is pregnant, nursing, or used for breeding
• is taking any other medications, supplements, or flea/tick products, including:
  • Give WITH food, separate from other oral drugs (binders adsorb co-administered drugs)
  • Vitamin K absorption (sevelamer)
  • Citrate (aluminum)

Storage and handling

Aluminum: bulk dried powder (compounding-friendly). Lanthanum: Renalzin gel on food. Sevelamer: tablets/capsules — give with meals or wasted.

Good to know

• A binder not given with the meal does nothing — it must be in the gut lumen with dietary phosphate; the timing rule IS the therapy.
• Ladder logic: aluminum (cheap, effective, constipation + long-term toxicity) → lanthanum/sevelamer (safer chronic profile, expensive, feline-friendly formats like Renalzin food-gel).
• CKD bone-mineral package: phosphate binder + renal diet (+ calcitriol when indicated) — phosphorus control outperforms almost every other CKD intervention for survival.
• Separate other oral meds by ≥2 h — the binder doesn't discriminate between phosphate and your drug.