can you give a cat his medicine late?

[Wyndee]

i got my cat some dewormer and i gave him his first dose 14 days ago as of yesterday. well the package said to give it to him on day 14 and i wasnt home yesterday.. So is it ok for me to give it to him today as in day 15? i guess what im trying to ask is, would it still be effective because it is day 15 instead of day 14? Please help me!! LOL thankss