If you are taking HIV PREP medication, you may want to consider switching to an oral form. It is important to discuss any changes to your dosage with your healthcare provider. Typically, you can take an oral form of PrEP until your next injection. How To Know About HIV PREP Oral Form Afterward, you should return to your regular injectable schedule every eight weeks. Oral my prep may not be effective for everyone. To avoid any problems, consult your healthcare provider before switching.