Over the weekend my cat (10 years old, female, spayed) developed some kind of urinary problem (she was going to the litter box every 5 minutes, only producing a few drops). She went to the vet on Monday morning and the vet gave her an injection of simbadol (1.8mg/ml, 0.8ml dose, so 1.44 mg for a 13.75 pound cat) to treat her pain/discomfort.
The vet warned me that the medication would make her high. An hour after returning home she started drooling. I called the vet and they said drooling is normal on this medication (I told them that she was producing Santa Claus worthy beards, and they said that was fine, just try to keep her clean).
I tend to associate foaming drool (like she's doing) with anxiety. Is the drug making her anxious? What other reasons could the drug be making her drool like this?