Viread – brand name

tenofovir DF – generic name

Viread belongs to a class of HIV drugs called nucleotide/nucleoside reverse transcriptase inhibitors (NRTIs or “nukes”). Viread is the only approved nucleotide reverse transcriptase inhibitor. There are many approved nucleoside reverse transcriptase inhibitors, such as Retrovir (zidovudine or AZT) and Epivir (lamivudine or 3TC). All NRTIs work in a similar way.

The NRTIs block reverse transcriptase, a protein that HIV needs to make more copies of itself. This may slow down HIV disease.

The Food and Drug Administration (FDA) has approved Viread for use in combination with other HIV drugs for the treatment of HIV infection in adults over 18 years old.

Viread comes in 300 milligram (mg) tablets.

The dose is one tablet, once a day.

If you have a kidney problem, your dose of Viread may need to be lowered.

Viread must be used with other HIV medications to treat HIV.

You can take Viread with food or on an empty stomach, but taking it with food may cut down on nausea or other side effects.

Some people use Viread in a combination pill called Truvada, which contains Viread plus Emtriva (emtricitabine or FTC).

Viread is one of the easiest HIV drugs to take—you take one pill, once a day. Once-daily drugs are convenient but more demanding, because good adherence is crucial. Missing or skipping doses can cause your blood levels of the drug to fall too low and resistance can develop. When your virus becomes resistant to an HIV medication, that drug may stop working.

Viread can be used if you are beginning treatment for the first time.

Viread may be a good choice for people who need to switch from other NRTIs, such as Retrovir, Epivir, Zerit (stavudine or d4T), Videx EC (didanosine or ddI), or Hivid (zalcitabine or ddC), due to the development of resistance.

Viread may not be effective for people whose HIV is resistant to certain drugs.

Your doctor can run a resistance test to help determine whether Viread is likely to work for you.

If your virus develops resistance to Viread then it may stop working or not work as well for you. You also may not get as much benefit from the other NRTIs.

Sometimes taking more than one medication can cause drug interactions. Viread can increase Videx EC levels in the blood – this might increase the risk of side effects caused by Videx EC, such as pancreatitis (damage to the pancreas) and peripheral neuropathy. If you are taking these drugs together, your doctor will likely lower your dose of Videx EC and monitor you for side effects. Because of concerns about the use of Viread with Videx EC, it may be best to avoid this combination altogether.

Viread reduces Reyataz (atazanavir) levels in the blood. If you are taking these drugs together, your doctor should also prescribe a low dose (100 mg) of Norvir (ritonavir) to increase or “boost” the amount of Reyataz in the bloodstream.

The following regimens containing Viread should not be used:

• Viread plus Epivir plus Ziagen (abacavir) or Videx EC
• Viread plus Videx EC plus Sustiva (efavirenz), Viramune (nevirapine), or Rescriptor (delavirdine) in patients new to HIV therapy

Taking certain drugs, such as Kaletra (lopinavir/ritonavir) and Reyataz, with Viread can change the amount of each drug in your blood. Other drugs, such as Vistide (cidofovir), Cytovene (ganciclovir), and Valcyte (valganciclovir), which are used to treat viral infections, can make some Viread side effects (like kidney problems) worse. Your doctor may need to adjust the doses of your drugs to avoid under- or overdosing.

Be sure your doctor knows about all the medications you are taking (including over-the-counter, prescription, street drugs, and herbs), even if you only use them occasionally.

For more information and additional resources to check interactions between the particular drugs you are taking, see our info sheet on drug interactions.

So far it seems that most people find Viread easy to tolerate, but it is possible that uncommon long-term side effects could show up later.

If you do experience any side effects from Viread, they are likely to be temporary and go away as your body adjusts to the medication. If you experience any of the side effects listed below, call your doctor for advice. Do not just stop taking your medication.

• Nausea
• Vomiting
• Diarrhea
• Intestinal gas (flatulence)

More serious side effects:

• Kidney problems: Have your creatinine (kidney enzyme) levels monitored regularly. High levels can indicate kidney damage.
• Bone problems such as osteoporosis or osteopenia (brittle bones): Since women with HIV may already be at higher risk for bone problems, it is important to get enough calcium and vitamin D and to ask your doctor about a bone mineral density test.
• An increase of lactic acid in the blood ( lactic acidosis), an enlarged and fatty liver, and liver failure have been reported in people using NRTIs. Lactic acidosis is a rare but potentially fatal side effect. Symptoms include nausea, vomiting, or stomach pain; feeling very weak and tired; shortness of breath.
• Lipodystrophy, which may include elevated blood sugar (glucose), elevated lipid levels ( cholesterol and triglycerides), and fat gain or loss in certain areas. The exact causes of lipodystrophy are not known, but may include HIV and/or HIV drugs. It is unclear if Viread will cause or impact symptoms of lipodystrophy. For more information on lipodystrophy, see our info sheet.

If you are experiencing persistent, unusual, or serious side effects, call your doctor right away.

Study 903 looked at 600 people who had not taken HIV drugs before, including 26 percent women, or about 156 women. In this study, Viread plus Epivir plus Sustiva and Zerit plus Epivir plus Sustiva worked about equally well. But elevated blood fat levels and fat loss in the arms and legs (lipoatrophy) were less likely in people taking Viread.

Study 907 looked at 550 people who added either Viread or a placebo (sugar pill) to their existing HIV regimens. This study included 15 percent women, or about 82 women. After 24 weeks, 19 percent of those taking Viread achieved HIV viral loads below 50 copies, compared with just 1 percent of those taking the placebo.

In July 2003, GlaxoSmithKline announced that it had to stop a trial (ESS30009) early after it showed that a once-daily triple NRTI regimen of Viread plus Epivir plus Ziagen did not work as well as Viracept plus Epivir plus Ziagen in people who had not taken HIV drugs before.

Data was analyzed from 194 participants. After eight weeks, 49 percent of those taking Viread did not respond to treatment, compared with 5 percent of those taking Viracept. Similarly, at the International AIDS Society conference in July 2003, researchers reported that 58 percent of the 19 participants (including 3 women) in another study also did not respond to Viread plus Epivir plus Ziagen. This triple-NRTI regimen does not appear powerful enough to suppress HIV in many people, and the virus can quickly develop resistance to these drugs when used together.

In terms of side effects, research has shown that the pharmacokinetics of Viread (how the drug is processed by the body) are similar in women and men. But past studies of medical records indicate that women (especially overweight women) taking NRTI drugs are more likely than men to develop elevated lactic acid levels and enlarged fatty livers. In addition, Viread can reduce bone mineral density.

Studies have shown that pregnant women who use HIV drugs can greatly reduce the risk of passing HIV on to their babies. There have been no formal studies on the use of Viread during pregnancy.

Check with your doctor about the best treatment options for you and your baby if you are thinking of getting pregnant.

Click this link for more information about pregnancy.

Viread is also active against hepatitis B virus (HBV). However, it is not FDA approved for this use.

Get tested for hepatitis B before you start taking Viread to treat HIV. If you are co-infected with HIV and HBV, speak to your doctor about treatment options. In addition, if you are taking Viread for HIV treatment, discontinuing the drug may result in worsening hepatitis symptoms.

People who are starting HIV treatment for the first time may develop Immune Reconstitution Syndrome or IRS (also called Immune Reconstitution Inflammatory Syndrome or IRIS). IRS can happen as a result of the immune system getting stronger and responding to an HIV-related infection such as Mycobacterium avium infection (MAC), cytomegalovirus (CMV), Pneumocystis jirovecii pneumonia (PCP), or tuberculosis (TB). People may have been treated for these infections in the past or not even know they have them. If you notice any unusual symptoms soon after starting HIV drugs for the first time, let your doctor know right away so you can be evaluated and, if necessary, treated.

1		Karras, A., et. al. (2003). Tenofovir-related nephrotoxicity in human immunodeficiency virus-infected patients: three cases of renal failure, fanconi syndrome, and nephrogenic diabetes inspididus. Clinical Infectious Diseases, 36(8). 1070-1073.
2		Schooley, R., et. al. (2002). Tenofovir DF in antiretroviral-experienced patients: results from a 48-week, randomized, double-blind study. AIDS, 16(9). 1257-1263.
3		Squires, K., et. al. (2002). Tenofovir DF: a 48-week final analysis from a phase III randomized, double blind placebo controlled study in antiretroviral experienced patients. 9th Conference on Retroviruses and Opportunistic Infections. Seattle, WA. Abstract P 413-W.
4		Staszewski, S., et. al. (2003). Efficacy and safety of tenofovir DF versus stavudine when used in combination with lamivudine and efavirenz in antiretroviral naïve patients: preliminary interim 96 week results. 10th Conference on Retroviruses and Opportunistic Infections. Boston, MA. Abstract 564b.