Some pharmacies especially compounding pharmacies can flavor a liquid medicine. If you see that it's just not working at all you may have to call your pediatrician and see if they can do a shot in that situation if you don't see improvement.

You should ALWAYS listen to the doctor. But to try to give you some comfort, when a child is autistic, their symptoms do mimic other things.
My daughter, who’s now 20, they thought she had ODD & she doesn’t, but when she was young she was a crazy terror:)
She also would only eat maybe 4 things & it all had to be soft foods. Now she’s eating toquitoes & pizza.
My other daughter is 9, also autistic & has adhd, will also only eat 4-5 foods & they have to be soft, except she loves sugar. I’m in no way saying the doctor(s) are wrong at all!!!
But from only my experience we had been told things that worried us to no end..that our daughter would never speak or she would never be able to read & she’s in college today.
As both the girls have gotten older the things that were an issue in the toddler years are gone, but new issues have taken the place, it changes & evolves as they age. At least that’s what I’ve experienced. All the best 🧡

My daughter has to take daily medication, a liquid, & hates it.
I give her some honey first..then the medicine..some water..& then another small spoon of honey. It works. We used to try whipped cream first but the honey lingers longer in her mouth to try to kill some of the medicine taste. Good luck:)

Thanks, Tiffani.
To be honest, my grandson has not been formally diagnosed with ODD. Perhaps I have jumped to conclusions!
We humans can be pretty complex at times!

In my household, we have an ongoing challenge with my five-year-old. He refuses to take liquid Tylenol, so we've switched to kid-safe tablets. Even with the tablets, giving him the medication is still a big struggle. However, when he had an ear infection, he had to take liquid antibiotics, and we had to negotiate with him every time he needed to take the medicine.