It can make you little dizzy, I've heard that some people have dizziness. Talk to your neurologist about it. I've been on C/L 25/100 for right around 25yrs. It was a miracle drug for me, my husband was diagnosed in 96 with cancer. I had no time to deal with PD I had a full plate. I hope you find that one medicine to help you like I was do lucky. I'm still on the same drug at the same mg, It only been recently that I have 2 more meds. They really work also.
Love Susan

Yes, dizziness is a known side effect of Carbidopa-Levodopa. The big danger that some doctors overlook is that Carb-Levo also has the side effect of lowering blood pressure, so if he is also taking meds to lower his blood pressure, he may need to have the BP med dose lowered or even to be weaned off the BP med entirely. Falling is to be avoided!

I had a terrible time with it the first few weeks until my dr got smart and started me out like 1 morn and 1 at night for a week then added one at noon for a couple of weeks until I was able to tolerate the full dosage. It took a long time but was worth it because I had given up on taking it at all because it made me so sick. So short answer to your question is probably. Most everyone I’ve talked to it has made them sick at least at first until they can get used to it. But it is a good idea to talk to your doctor about it.

It could be affecting your blood pressure.

My husband takes two tablets three times a day and doesn't get dizzy. He does have some stomach issues though.

I take 2 three times a day and 1 in the evening with an extended release at bedtime. No problem, so you should ask your doctor.