Best drug to use for oral infections in fiv cats and L-Lysine

I would like to know what would be the best drug to treat oral infections in possible fiv possitive cats. I have tried Metronidazole without success, mostly because it is virtually impossible to give them tablets due to their mouths being so sore. I tried crushing the tablets and diluting with water to give orally but that is an even worse option lol! I heard it comes in liquid forms but my vet has not been able to locate it to purchase for me. Is there any better and easier liquid drug effective to combat oral infections that I might suggest to my vet? Also, I do give them Amoxi but it does not completely erradicate the oral problems--only cuts it down somewhat. Also was wondering about the effectivness of L-Lysine for FIV cats and ones with upper respitory problems
Kindest Regards,
C.Tipling

[Aleda M Cheng, D.V.M., C.V.A]

Azithromax and Clindamycin are both good antibiotics for oral lesions and come in liquid forms.

[clight]

Thank you so much for the antibiotic advice, but could u tell me if u believe L-Lysine would help these kitties fight upper respitory which they frequently get? And if so how much to give adult cats?
TYVM!