This lesson corresponds to the Contraindications section in the Clinician’s Module of the WHO Implementation Tool for Oral PrEP. It provides an overview of contraindications to the use of Oral PrEP. It identifies the three contraindications for a client starting oral PrEP and describes the possible symptoms of acute HIV infection that can be used to help rule out recent infection. It also explains how to manually calculate creatinine clearance using the Cockcroft-Gault equation. It then summarizes conditions that may predispose clients to decreased creatinine clearance and identifies four factors that can influence serum creatinine levels. After you have completed this lesson, please take the short quiz found below. Estimated Duration: 15 minutes.