Could you please let me know how much can give my eight year old.

My son has been to the doctor for strep throat and he is better but now he is coughing alot and i have some of the Vi-Q-Tuss left from before but I know he weighs more now how much can I give him. He is coughing so much it sometimes makes him almost vomit. It is not outdated and I would like for him to be able to rest tonight.

Thanks

Angie