My son is allergic to Penicillin, Lorabid, Cedax, Cipro, Neomycin, and Erythromycin... he has just been told to take Clarithromycin but is concerned since the warning says not to take if allergic to Erythromycin... He just finished a Z-pack about 2 weeks ago. He has acute Laryngitis, acute sinusitus, and ETD. What is your opinion on taking this Clarithromycin?