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Other Names: Viread®
Manufacturer: Gilead Sciences

What is it?

Tenofovir is an antiretroviral medication, specifically a nucleotide reverse transcriptase inhibitor. It is used to treat HIV, a retrovirus. Retroviruses use the genetic material in the body’s cells to produce more virus which can infect other cells.

How does it work?

Tenofovir interferes with the life cycle of HIV to stop it from producing more virus. Specifically, it ties up the reverse transcriptase enzyme so it cannot build the genetic material needed to make more virus and infect more cells. This medication is used in combination with other antiretroviral drugs to inhibit HIV reproduction.

How do I take it?

  • Tenofovir is available as a 300mg tablet.
  • The usual dose is 1 tablet (300mg) once a day at the same time every day.
  • Tenofovir may be taken with or without food. Food will increase the amount of medication that is absorbed.

It is extremely important that you take tenofovir and any other antiviral medications exactly as directed. You should set up a system that will help you remember to take your medicines so that you do not miss any doses. If you miss a dose, take it as soon as possible; however, if you skip a dose, do not take two doses at once. Do not stop taking the medication for any reason at any time unless you are directed to do so by your study clinician. If you are unable to continue taking your medication due to side effects, you should contact your study clinician immediately.

Special Considerations

  • Tenofovir should be stored at controlled room temperature in a dry place, out of the reach of children.
  • Please bring your medication bottles (empty and partially used) to each study visit.


Some drugs taken together may have interactions that cause illness or impair the effectiveness of the drugs. It is a good idea to always check with your provider before taking any other medications, prescription or otherwise, to be sure it will not interact with tenofovir.

Tenofovir increases the levels of didanosine (Videx®) in the blood stream. This may lead to side effects associated with didanosine. If you take didanosine, please talk with your provider or pharmacist about how to limit the possibility that side effects will develop.

Side Effects

Not everyone experiences side effects. When they do occur, they may be mild, moderate or severe. Some side effects cannot be felt by the patient but can be found through laboratory tests, so it is important to see your provider regularly for checkups so that side effects can be detected early and treated.

Possible side effects of tenofovir include upset stomach, nausea, vomiting, and diarrhea.

Nucleotide reverse transcriptase inhibitors such as tenofovir have been associated with a condition called lactic acidosis. Lactic acidosis is a build-up of lactic acid, a byproduct of muscle metabolism, in the blood. Early symptoms can be vague and non-specific and can include nausea, vomiting, fatigue, abdominal pain, sudden unexplained weight loss, and shortness of breath. If you are experiencing these symptoms and they cannot be explained by other causes, please contact your provider immediately. Although lactic acidosis is a rare condition, it can be life-threatening if not treated.

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