06/03/2026
Three medications. Non-negotiable. 💉⚠️
If a dog is receiving STELFONTA® treatment for a mast cell tumor, the essential medications are not “optional prep work.” They are a critical part of the treatment protocol.
And yes, without them, a dog can potentially experience a severe, even life-threatening, reaction.
Here’s why:
One of the major mechanisms of STELFONTA® is mast cell degranulation, meaning mast cells release inflammatory compounds, including histamine, as the tumor breaks down.
That’s exactly why these medications matter. ⬇️
💊 Corticosteroid (like prednisone)
Started at least TWO days before treatment to help reduce inflammation and minimize complications
💊 H1 blocker (like diphenhydramine/Benadryl)
Helps counteract histamine release associated with mast cell degranulation
💊 H2 blocker (like famotidine/Pepcid)
Helps protect the gastrointestinal tract from excess histamine effects
Per the protocol, the H1 and H2 blockers must be started the morning of treatment, but I have the owners start all three medications above two days before treatment (plus the gabapentin the morning of - see below)
These medications significantly decrease the risk of serious adverse reactions during and after treatment.
Pain medications are also prescribed. Personally, I often have my clients administer gabapentin at home the morning of treatment as well.
And thankfully, there is a FREE Essential Medication Tracker available on stelfonta.com to help owners stay organized before treatment day. 🙌🏻
Bottom line:
If your veterinarian emphasizes these essential medications, it’s because they matter A LOT and truly are essential.
Questions about STELFONTA® prep medications?
Drop them below. ⬇️
