My 13 yr son has nose infection & is taking biaxin (clarithromycin) 500 mg for 10 days. Total of 20 pills. And nasonex spray 2x for 10 d is this too much or correct.

Depends. The answer depends on the severity of the infection and the weight of your son etc. If he was very thin and of low weight, than a lower dose could be used, etc. Your prescribing physician is aware of his infection and weight I would hope. Overall, that dose of both medications is certainly acceptable. Good luck.