Medication-MedicationID, BrandName, GenericName

select max(GenericCount)
from
(
    select count(*) GenericCount, GenericName
    from yourtable
    group by GenericName
) x

select count(*) GenericCount, GenericName
    from yourtable
    group by GenericName

SELECT MAX(COUNT(GenericName)), GenericName FROM MedicationTable GROUP BY GenericName