Toceranib phosphate

What is this medication for?

• Patnaik grade II/III recurrent cutaneous mast cell tumors (± regional LN) — FDA-approved; investigational: sarcomas, carcinomas, melanoma, myeloma; metronomic combos

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.

• The "start the stomach/intestinal protectants before day 1" strategy (antacid + antihistamine ± prednisone, sucralfate if hemoccult+) prevents most toxicity dropouts.

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

• Diarrhea, loss of appetite, weight loss, lameness, blood in stool (Most common — the label's big five)
• Neutropenia, hypoalbuminemia, muscle cramping (Occasional)

Worth a phone call to your veterinarian

• Severe stomach/intestinal bleeding (Requires immediate interruption/dose-reduction)

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

• Thromboembolism (incl. pulmonary), vasculitis/edema, pancreatitis, seizures, nasal depigmentation, coat color change, epistaxis (Less common but notable)

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

• has or has had: Breeding/pregnant/lactating bitches
• has or has had: Stop ≥3 days before surgery (vascular dysfunction → edema/thromboembolism risk)

• is pregnant, nursing, or used for breeding
• is taking any other medications, supplements, or flea/tick products, including:
  • Loperamide
  • NSAIDs + prednisone
  • CYP-metabolized drugs
  • Ketoconazole/azole CYP inhibitors

Storage and handling

Handle with care ( cytotoxic tablet); client information sheet per label; don't split tablets.

Good to know

• The first FDA-approved veterinary cancer drug — a pharmacy milestone: Kit-mutation-driven MCT therapy with targeted (not cytotoxic) logic.
• The "start the stomach/intestinal protectants before day 1" strategy (antacid + antihistamine ± prednisone, sucralfate if hemoccult+) prevents most toxicity dropouts.
• 3.25 mg/kg is the label, 2.5–2.75 mg/kg is the real-world tolerance refinement — exam answer vs practice wisdom.
• Lameness/muscle cramping + hypoalbuminemia are the odd-signature toxicities that distinguish toceranib stomach/intestinal panels from classic chemo.