Pharmacokinetics: HIV Drugs Allie Punke (apunke@uthsc.edu)

Renal function Patients with HIV are at an increased risk of having nephropathy that can lead to ESRD DJ is a Caucasian female who was just diagnosed with HIV. When/should you recommend for her to be screened for renal function? What are you specifically screening for when performing renal function tests?

Renal function CG is a HIV+ (diagnosed about a year ago) African American male. At your appointment with him today, he tells you he sometimes forgets to take his medications for HIV. The CD4 and HIV RNA count today is 150 and 900, respectively. His renal function was stable when he was diagnosed with HIV. Should we check his renal function today?

Renal function When to screen patients for renal function: Screen ALL patients when they are diagnosed with HIV Yearly screening if patients are at high risk African American CD4<200 HIV RNA>400 Family history of renal problems

Hepatic function What makes HIV + patients at increased risk for liver function abnormalities? 1. Patients may be co-infected with HBV or HCV (If co-infected, patients have increased risk of drug induced liver injury) 3. Medications (Nevirapine/TB drugs)

Hepatic function GP is a 28 YO AA male who was just diagnosed with HIV. How often should we monitor his hepatic function? ALT/AST Q 6-12 months.

Dose adjustments Patients with renal or hepatic issues will most likely: Not be able to take medications that are _________. Will often require _________ doses Will be advised to take medications _________ HD session. Will or will not require trough concentrations.

Dose adjustments Generally speaking…. Dose adjustments (hepatic/renal) should be made for the following drugs: 1. INST 2. NNRTI INST (integrase inhibitors): dose adjustments not commonly needed for INST’s. NNRTI; renal adjustment less common, adjustments not needed with mild impairment (most have no dosage recommendation/no recommendation for child pugh C) PI: hepatic dose common, renal adjustment is less common NRTI: most need renal adjustment

Dose adjustments 3. PI 4. NRTI

Dose adjustments AB is a 45 YO African American HIV + male. His renal function has been gradually declining, and now he is requiring dialysis on M, W, F. His medications include: efavirenz, maraviroc, enfuvirtide, tenofovir, atorvastatin, amlodipine. Which medication only needs to be given once a week? When should the other HIV medications be dosed?

Dose adjustments In general, patients with renal/hepatic issues should avoid co-formulated products; however, there is one combination medication which has lower renal cut-off that patients may be on until renal dysfunction becomes worse: Truvada (combo of emtricitabine and tenofovir both have same cut off for renal function)

Dose adjustments T/F: Emtricitabine is a member of the NNRTI class, which generally does not require renal dose adjustment. T/F: Atripla does not require dose adjustment for patients with decreased renal function. T/F: Stribild can be recommended without testing renal function when initiating, but yearly renal function screening is recommended. False (NRTI, requires renal adjustment) False (has tenofovir and emtricitabine in it, which do) False (has tenofovir/emtricitabine in it) not rec <70. D/C if <50

Drug monitoring T/F: Most patients with HIV receiving antiretroviral medication should have their medications monitored through the use of drug concentrations T/F: Patients who do have their HIV medications monitored experience quicker time to undetectable RNA load and less side effects T/F: Monitoring HIV medications is recommended in HIV guidelines due to clinical trials showing that monitoring improves clinical outcomes False. NOT the standard of care.

Dose adjustments A patient who was recently diagnosed with HIV has been on anti-retroviral therapy for the past 3 months. She reports being extremely adherent (the pill counts also show she has been adherent). However, her CD4 count is still very low and her RNA is quite high. What can we consider doing? 1. DDI 2. Change in physiologic state 3 Pregnancy 4. Pretreated patient experiencing virologic failure Use of alternative dosing regimens Lack of expected virologic response in adherence individuals

Pre-exposure prophylaxis A 23 YO Caucasian female with history of IV drug abuse asks if there’s any medication to reduce her chances of acquiring HIV. What medication would you want to tell her about? If you give her the medication, when would you want to schedule a follow up visit? Truvada (TDF/FTC 300/200) AT LEAST Q3 months

Pre-exposure prophylaxis What are some things to monitor for a patient receiving pre-exposure prophylaxis? If a patient becomes HIV + while on prophylaxis (and the diagnosis is confirmed and CD4 count is ordered), what should we do?

Pre-exposure prophylaxis For all groups (MSM, heterosexuals, IVDU)…what must we make sure they do NOT have before initiating HIV pre-exposure prophylaxis? Documented neg HIV test, no signs/symptoms of HIV infection, normal RF/no CI meds, documented hep B virus and vacc status

Pre-exposure prophylaxis Should we initiate it in these patients? 1. Gay male who was diagnosed with gonorrhea 5 months ago. 2. IV drug abuser who sometimes shares needles with her friend who was just diagnosed with HIV 3. Heterosexual male who thinks he may be having symptoms of HIV after a previous partner informed him that she is HIV+

Pre-exposure prophylaxis

summary Recognize the need to monitor for renal and hepatic function in HIV + patients Recognize the classes of medications as well as the combination products that generally need to be adjusted for renal or hepatic function Know the drug used for pre-exposure prophylaxis Know which patients are eligible for pre-exposure prophylaxis

Questions about this or previous session? Good luck!