Since the feline MDR1 mutation was more recently discovered than the canine MDR1 mutation there has been less research on the topic. The WSU PrIMe® research team is working to determine if other drugs commonly used for treating cats are substrates for feline P-glycoprotein (i.e., have the potential to cause toxicity in cats with the MDR1 mutation).
The list of problem medications for dogs and cats is kept current and includes only drugs that have undergone peer-reviewed publication. Updates to this list occur as new research is published. For the most up-to-date dosing recommendations, including drugs currently under investigation, please submit questions through MDR1Caddie.
| Drug (Active Ingredient) | Brand Name | Recommendation |
|---|---|---|
| Amlodipine | Norvasc; Istin | Contact WhisPurrTM for dosing recommendations |
| Capromorelin | Elura | Contact WhisPurrTM for dosing recommendations |
| Chemotherapy | Contact MDR1Caddie™ for dosing recommendations. | |
| Cisapride | Not applicable – compounded formulation | Contact WhisPurrTM for dosing recommendations |
| Cyclosporin | Atopica | Contact WhisPurrTMfor dosing recommendations |
| Emodepside | Profender | Contact WhisPurrTMfor dosing recommendations |
| Eprinomectin | Nexgard Combo | Do not use in cats with the MDR1 mutation. |
| Ivermectin | Heartgard | If used in accordance with label, the dose of ivermectin is low enough to be safe for cats with the MDR1 mutation. For other formulations of ivermectin contact MDR1Caddie™ for dosing recommendations |
| Loperamide | Imodium | At doses used to treat diarrhea, this drug will be expected to cause neurological toxicity in cats with the MDR1 mutation. We recommend avoiding loperamide in cats with the MDR1 mutation. |
| Methylprednisolone | Medrol; many generics | Contact WhisPurrTM for dosing recommendations |
| Milbemycin | Interceptor | If used in accordance with label, the dose of milbemycin is low enough to be safe for cats with the MDR1 mutation. For other formulations of milbemycin contact MDR1Caddie™ for dosing recommendations. |
| Moxidectin | Advantage Multi, Bravecto Plus | Oral ingestion of this topical product would be expected to cause neurological toxicity in cats with the MDR1 mutation. |
| Rapamycin | Felycin-CA1 | Contact WhisPurrTM for dosing recommendations |
| Sirolimus | Felycin-CA1 | Contact WhisPurrTM for dosing recommendations |
| Vinblastine | See Chemotherapy | |
| Vincristine | See Chemotherapy | |
| Vinorelbine | See Chemotherapy | |
| Selamectin | Revolution Plus | Oral ingestion of this topical product would be expected to cause neurological toxicity in cats with the MDR1 mutation. |