The MastAttack 107: The Layperson’s Guide to Understanding Mast Cell Diseases, Part 79

92. Why is ketotifen not FDA approved? How do I get it?

Ketotifen is a mast cell stabilizer that is also an H1 antihistamine. It is regularly cited by mast cell patients as one of the more effective meds for managing mast cell disease, especially food intolerance. But it can be tricky to get ahold of in the US.

Firstly, ketotifen actually is FDA approved. It is FDA approved in eye drops. However, the formulation typically used by mast cell patients is oral. Oral ketotifen has not been approved in the US, but it’s not because it’s dangerous. It’s because it was never submitted to the FDA for approval. And why was it not submitted? Again, not because it’s dangerous. At the time, the manufacturer did not feel that there was enough of a market to justify the time and expense of an FDA submission when there were so many other H1 antihistamines available both over the counter and with prescription. It’s that simple.

So how do you get ketotifen in the US? You can import it from abroad for personal use as a mast cell patient, but there is an easier way: ketotifen capsules can be bought through compounding pharmacies who order the powder and put it in capsules. The most common strength for capsules is 1mg. Your provider just writes a prescription for it and the compounding pharmacy puts it together for you. As a side note, insurance often does not cover compounded medications so be prepared for that.

Because there wasn’t an FDA submission, there is less safety and dosing information available. In adults, dosing typically starts at 2-3mg a day. Some providers use much higher doses, even going upwards of 20mg per day in some instances. Again, we don’t have study data on this drug in mast cell disease, so conservative dosing is common.

Ketotifen is available as a tablet without a prescription in many countries, including Canada.