Tenofovir alafenamide (TAF) is indicated for adult patients with chronic hepatitis B virus (HBV) infection with compensated liver disease at an oral dose of 25 mg/day. TAF is a more stable prodrug in the plasma than tenofovir disoproxil fumarate (TDF), leading to decreased plasma exposure of tenofovir. Decreased exposure is thought to reduce the risk of long-term TDF toxicities, such as nephrotoxicity and decreased bone mineral density (BMD). TAF, a nucleotide reverse transcriptase inhibitor, has the same mechanism of action as TDF. The results of phase III primary trials and extensions showed that TAF is noninferior to TDF at suppressing the HBV viral load in treatment-naive and treatment-experienced HBeAg-negative and HBeAg-positive patients at 48 weeks, 96 weeks, and 144 weeks of therapy. The most commonly reported adverse events were headache, abdominal pain, fatigue, cough, nausea, and back pain. At all evaluated time points (out to 144 wks of treatment), patients who received TAF had less risk of nephrotoxicity and less of a decline in BMD than the patients who received TDF. TAF appears to be safe in patients with a creatinine clearance (Cl ) above 15 ml/min; however, TAF is not currently recommended in patients with an estimated Cl below this threshold. TAF is safe in patients with mild hepatic impairment but is not currently recommended in patients with moderate or severe hepatic impairment (Child-Pugh class B or C).

Highly active antiretroviral therapy (ART) and its widespread availability have revolutionized the landscape of HIV care and patient outcomes, transforming infection with HIV into a manageable chronic condition rather than a life-limiting disease. This transformation has created an older patient demographic. The effect that older age has on the outcomes of ART is not completely understood. Limited data are available in older individuals due to underrepresentation in clinical trials. To better understand this relationship, we conducted a literature search to assess the impact of older age on the outcomes of ART in the older HIV-infected population, including immunologic and virologic outcomes, mortality, disease progression, toxicity of ART, and pharmacokinetic considerations. In addition, package inserts of antiretroviral (ARV) medications were reviewed for efficacy, safety, and pharmacokinetic information pertaining to the older population. Most studies in older adults (50 yrs or older) demonstrated slower and blunted CD4 immune recovery but better virologic suppression in response to ART. Higher rates of mortality and faster disease progression have been observed in adults 50 years and older, particularly during the first year after ART initiation. HIV-infected patients aged 50 years and older appear to be at greater risk for certain ART-associated toxicities including nephrotoxicity, decline in bone mineral density and bone fracture, symptomatic peripheral neuropathy, and cardiovascular disease including myocardial infarction. The available literature suggests that clinicians should consider avoiding agents such as tenofovir disoproxil fumarate (TDF) in older patients with risk factors for renal impairment and/or osteoporosis. If TDF is used in patients aged 50 years or older, more frequent monitoring should be considered. Older age was a significant predictor for higher atazanavir exposure and higher lopinavir trough concentration at 24 weeks. The clinical implications of these findings are unknown. It is imperative that future development of novel ARV drug therapies includes a greater proportion of older subjects in clinical trials.

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Chronic hepatitis C is a common cause of liver-related morbidity and mortality. Ledipasvir/sofosbuvir is a combination of 2 directacting antiviral agents that has been approved for use in patients with genotype 1, 4, 5, or 6. This approval is based on multiple phase 3 studies in which the rate of sustained virologic response exceeded 90% for 12 or 24 weeks of treatment, depending on the patient population. For some patients, the addition of ribavirin is required. Ledipasvir/sofosbuvir is well tolerated, with the most commonly reported adverse events being fatigue and headaches.