Standard Dose: One 300 mg tablet once-a-day, with no food restrictions (with or without food). Dosing frequency needs to be adjusted for people with decreased kidney function. Take missed dose as soon as possible, but do not double up on your next dose.

AWP: $500.09 / month

Manufacturer contact: Gilead Sciences, Inc.,
www.viread.com, 1 (800) GILEAD5 (445–3235)

AIDSInfo:1 (800) HIV–0440 (448–0440), www.aidsinfo.nih.gov

Overall, fairly well tolerated, however, individuals may experience the following: nausea, headache, diarrhea, vomiting, asthenia, flatulence, abdominal distension/pain and anorexia. Less common side effects of tenofovir occurring with undetermined incidence include kidney toxicities and low blood phosphate. See AZT page for rare but potentially fatal toxicity with all NRTIs as a drug class.

The effect of tenofovir on children and individuals with severe hepatic (liver) impairment was not studied during drug development. However, since tenofovir is not metabolized by the liver (and appears to have less toxicity in the liver than the majority of the NRTIs), it is believed the impact on individuals with liver disease should be minimal.

Viread along with Emtriva (also available as Truvada and in Atripla) are considered a preferred NRTI combination by U.S. HIV treatment guidelines. The body clears 70–80% of Viread through the kidney and dosing adjustment is recommended for those with impaired kidney function. Serious kidney problems have been rare and the majority has been in those with pre-existing kidney disease or receiving nephrotoxic agents. However, the characteristics of renal toxicity are still being defined. The manufacturer recommends that individuals with impaired kidney function be monitored closely, especially in people with advanced HIV disease, even in people who did not start out with kidney disease. There have been about 20 reports on individuals who experienced severe kidney disorder including some taking Kaletra with Viread. Since Kaletra increases blood levels of Viread, it may increase the likelihood of Viread side effects.

Bad news in combination with Videx—barely raising T-cells in people who are undetectable, failure to reach undetectable in people who started with less than 200 T-cells and more than 100,000 viral load. A study found early failure (at 12 weeks) with Sustiva/Videx/Viread (12%, five out of 41 individuals) vs. Sustiva/Videx/Epivir (no failures at 12 weeks), so the combination of an NNRTI with Videx and Viread is not recommended.

Like Epivir, Viread has activity against hepatitis B, which may flare up when Viread is discontinued. While data is limited, Viread may have prolonged activity against hepatitis B even when resistant to Epivir. Viread selects for the K65R mutation (as do Ziagen and Videx), it was seen in 3% of the Viread treatment-naïve patients at three years in one study and 0% in two years in another study. But Viread may continue to be effective despite this resistance. AZT and Zerit maintain full activity and varying rates of continued efficacy are seen with Ziagen and Videx. In clinical trials reduced response to Viread was associated with multiple TAMs (thymidine analog mutations), specifically the M41L or L210W. Further research needs to be done in this area. Available in a combination pill with Emtriva called Truvada and it is also combined with Sustiva and Emtriva in a pill called Atripla.