You'll need to use multiple techniques to medicate a hedgehog. They are smart, will figure out what you are doing and will put a stop to it. So then it's on to the next set of tricks. Here are several things I (and others) have done. Keep with one until it stops, then move on to something else.
In no particular order:
Straight up medication - hold Loki in one hand, have the syringe ready in the other. Have him a bit balled up and facing you. Slide the syringe into the corner of his mouth. He'll likely fuss, so you'll need to approach several times. He may let you in on his own. Or may just get huffy and bite the end of the syringe. Both are your opportunity. You may get the whole dose in. You may not. It was extremely rare that I ever got the full dose in during one squirt. So you repeat the corner of mouth thing a few times.
A variation: instead of just meds in the syringe, make a "sandwich" of sorts with something he likes that passes easily through the syringe (test it out first). Babyfood turkey or chicken works well... doesn't clump like wet cat food. Pull up the babyfood first, then the meds, then back to the babyfood.
Forget the oral syrine entirely and mix some into an intensely flavored wet cat food. I've found the Blue Wilderness seems to work the best for this application. You only want a small amount, because you'll need Loki to eat the whole thing.
Get some syringes (with needle) from your vet. Use them to draw up the meds and inject mealies/waxworms (ie, whichever he prefers).
Go to a compounding pharmacy and have them mix his meds with roast chicken/turkey flavor. Or see if they'll give you a little bit of the flavor on its own. Touch the end of the syringe to the flavoring (do not use much at all, it is very strong). He'll be too busy licking and sucking on the oral syringe to notice you're pushing meds through. You might also try this with the fluid that comes from normal "human" tuna in a can that you might eat for lunch.
Meanwhile, give him some plain (non-medicated) food by syringe so that syringe is not 100% associated with nasty stuff. Also, sprinkle some acidophilus on his kibble to put good bacteria back in his body. He needs good bacteria in his gut to be able to digest food properly. Antibiotics have a tendency to kill the good stuff along with the bad stuff. So add some good stuff back in. With luck, he'll eat his kibble at a time other than directly after receiving the meds that will just kill it back off.
Whatever you do, patience is the key. He will eventually give you an opportunity to get in. You just have to remain calm, cool, and collected while he puts up a fuss.
