You may consider doing 12:12? One meal then fast 12 hours, second meal fast another 12. Or change your eating window? 8AM to 4PM? 10AM to 5PM? Those are the solutions I can come up with. Or eat a really low calorie vegetable? I think cucumbers have 70 or so calories. You could eat half of one and see if that helps.
My advice is to move your eating window to coincide with when you have to take your medicine rather than not eat or try to trick your stomach. If you have to take meds at 8am, for example, this means your eating window is 8am to 3pm and you fast from 3pm to 8am. I realize this may require a period of adjustment for you since that means you would basically only be getting breakfast and lunch and never dinner.
I just started IF and I take ADHD meds and I immediately noticed the same problem. I wasn’t getting sick to the point of throwing up, but it did make me feel “sick” and very unmotivated. I’m only on week two but yesterday was the first day I didn’t feel sick. My body eventually got used to it. Maybe yours will too.
I have a slew of medications that need to be taken in the morning and some at night.
I have found that over time, my stomach has adjusted to my meds with just water but it was rough for the first few weeks. I found drinking a large amount of warm water before taking my meds helped.