You can access PEP by coming to Sandyford during our opening hours. You do not need an appointment to access PEP. Out with these times please attend your local A&E department. PEP is most effective when started within 24 hours of exposure and can be effective up to 72 hours (3 days) after exposure. To be assessed for PEP, contact Sandyford during the day or Accident and Emergency Services when Sandyford is closed.