For an electronic prescription, you can only issue one prescription at a time.
For paper prescriptions, the rules are different. Up to three pharmaceutical benefit items may be included on a single PBS prescription form except for Authority required, Authority required (STREAMLINED) items and optometrist items.
These items must be written on individual forms. PBS and non-PBS items should not be listed together on one PBS prescription form.
Please see the PBS website for more information: https://www.pbs.gov.au/info/healthpro/explanatory-notes/section1/Section_1_2_Explanatory_Notes