I agree with using a syringe to get the medication as far back in the throat as possible so that the only thing that can happen is for the medicine to go down. Follow with some 7-Up or fruit juice.
My daughter was the absolute WORST at taking any type of liquid medicine. It didn't matter if it tasted like bubble gum or grape....forget it. She flat refused to take even cough syrup.
Believe it or not, at 2, she was taking pills like a champ. Seriously.
No fussing, fighting, crying, gagging. She would take a drink of juice, then the pill, and wash it down with more juice. It completely ended the torment of trying to get her to take her medicine.
It's what worked for her so maybe it's worth a try for your little one as well. He won't have to taste the medicine at all and at least you'll be sure he's getting a full dose.
My daughter's pediatrician suggested it after I discussed her screaming freakouts over the liquid. He told my daughter he had a "magic" new way and she trusted him. It worked!
My son, God bless his little heart, he never fussed about medicine or getting his immunizations, never whimpered when he had to get stitches in his knee, never cried when he had to have two days of I.V. antibiotics for a weird blood infection.
They probably would have had to induce my daughter into a coma to manage any of that.
All kids are different. Your little guy might do better with pills if he so hates the liquid. It's worth a discussion between you and the pediatrician.
Best wishes.
Best wishes.