Hello my name is Dr. Holloway but you can call me Dr. H, and I am a licensed veterinarian.
I am sorry to hear that your pet is battling cancer and needs to come off the pain medication that is making her comfortable. I do have some alternative pain management suggestions that are compatible with Gabapentin. The Amitryptilline will not be compatible with any of the other available pain management medication unfortunately, so either its dosage will have to be decreased (to avoid exacerbation of the effects) or it will have to be discontinued.
1) Fentanyl patch- this is a pure opiate and is usually applied to the pets skin several hours before surgery. It's effectiveness is only good for up to 3 days however.
2) Methadone- This is also an opiate used for pain management in dogs. Again Methdone also may exacerbate the effects of Amitryptilline when used in conjunction, so decreasing the dose of Amitrytilline or completely stopping the medication is advised.
This medication is available mostly as an injectable and the oral use has to be strictly monitored due to possible side effects. So if it is to be used Patti would have to be monitored in the hospital leading up to her surgery date.
3) Tramadol- this is also an opiate, it doesn't have nearly as much pain control as the other drugs mentioned. It should not be used along with Amitryptilline due to an increased risk of seizures, so it does appear to be quite a risk when used along with that medication when compared to the others.
So it does seem there are not a great deal of good options for Patti out there. They all come with their own limitations for use.
- Dr. H