DS5 was given some TRULY NASTY tasting antibiotic to take recently, and had to take it for THREE WEEKS! Now, he is actually very compliant re: taking meds, so I'm not sure whether or not this will help.
The doctor recommended to give him a potato chip or two before and after the medicine. The oil/salt coat the tongue and prevent the taste from being QUITE so horrible. It doesn't get rid of the taste issue, but it did help for DS5. The added thing here is that we don't eat chips often, so this was a real treat. I took DS to the store and let him pick out 3 different bags of chips, so he could decide what he wanted. He was then allowed 2-3 chips before and after the medicine, and no one else in the house was allowed to eat them.
Good luck with this. You'll get through it!