The prescription "i-ii q4-6h" means to take 1-2 units (pills, tablets, etc.) every 4-6 hours as needed. Therefore, the maximum number of units that can be dispensed for a 30 day supply will depend on how often the medication is taken. If the medication is taken every 4 hours, then a 30 day supply would require 180 units (1-2 units every 4 hours for 30 days). If the medication is taken every 6 hours, then a 30 day supply would require 120 units (1-2 units every 6 hours for 30 days). However, it's important to note that the actual number of units dispensed may be less than the maximum allowed by the insurance company or the prescribing physician.