Erie Family Health Centers (Dr. Foley); Hudson Headwaters Health Network (Dr. Farrell); Lancaster General Hospital Physicians Comprehensive Care, Penn Medicine, Lancaster General Health (Dr. Carr Reese) andrewvafoley@gmail.com
The authors reported no potential conflict of interest relevant to this article.
At PrEP initiation, acute or chronic HIV infection must be excluded with a documented negative HIV antigen/antibody test within 1 week of prescribing PrEP.5 The CDC guidelines provide an updated HIV testing algorithm (www.cdc.gov/hiv/pdf/risk/prep/cdc-hiv-prep-guidelines-2021.pdf, p 30-31, Figures 4a and 4b), which considers whether patients have received PrEP recently.
Patients with recent high-risk exposures or symptoms of acute HIV at the time of desired PrEP initiation should have an HIV-1 viral load checked with negative results before PrEP is prescribed. Additional criteria for PrEP include weight > 35 kg; screening for hepatitis B virus infection; screening for drug interactions; and drug-specific eCrCl cutoffs of > 60 mL/min for Truvada, > 30 mL/min for Descovy, and > 15 mL/min for Apretude.5
Studies regarding time to medication effectiveness are limited. Pharmacokinetic studies of Truvada demonstrate sufficient drug concentrations should be present in peripheral blood mononuclear cells and rectal tissue within 7 days of initiation of oral dosing and around 20 days in vaginal tissue.
Of note, while expedited partner therapy is used as a harm-reduction strategy to treat the sexual partners of patients diagnosed with certain STIs, PrEP is not recommended to be used in this way.
Ongoing monitoring with PrEP.Once oral PrEP is started, STI risk assessment and HIV testing via 4th generation antibody/antigen test should be completed at least every 3 months. PrEP oral prescription refills should be limited to 3 months. For patients receiving IM PrEP (Apretude), HIV testing via viral load and antibody/antigen testing should be done at the time of each injection (every 2 months).5