Hi Pat,
Really sorry to hear about your PE and hope it clears up soon. Are you sure that guy was a doctor? Tramadol is one of the most popular painkillers for pets.
Enjoy the drug break and even if your onc doesn't want to cut the dose too much long term, I'd definitely think about starting with a few days on 20mg to try to avoid a repeat of the horrendous start you had last time.