Tenofovir disoproxil fumarate (DF) (Viread) is used along with other medications to treat HIV infection in adults and children 2 years of age and older weighing 22 pounds (10 kilograms) or more. Tenofovir DF is also used to treat chronic (long term) HBV in adults and children 2 years of age and older weighing 22 pounds (10 kilograms) or more. Tenofovir alafenamide (AF) (Vemlidy) is used to treat chronic (long term) HBV in adults and children 12 years of age and older who have stable liver disease. Tenofovir is in a class of medications called nucleoside reverse transcriptase inhibitors (NRTIs). It works by decreasing the amount of HIV and HBV in the blood. Although tenofovir will not cure HIV, it may decrease your chance of developing acquired immunodeficiency syndrome (AIDS) and HIV-related illnesses such as serious infections or cancer. Taking these medications along with practicing safer sex and making other lifestyle changes may decrease the risk of transmitting the HIV virus to other people. Tenofovir will not cure hepatitis B and may not prevent complications of chronic hepatitis B such as cirrhosis of the liver or liver cancer. Tenofovir may not prevent the spread of hepatitis B to other people.

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

Tenofovir DF comes as a tablet and as an oral powder to take by mouth. The tablet is usually taken with or without food once daily. The powder is usually taken with food once daily. Tenofovir AF comes as a tablet to take by mouth. It is usually taken with food once daily. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take tenofovir exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Tenofovir DF oral powder must be added to 2 to 4 ounces of soft food such as applesauce, baby food, or yogurt. Stir the mixture with a spoon until well mixed. Consume the mixture right away to avoid a bitter taste. Do not mix tenofovir DF oral powder with liquid.

Continue to take tenofovir even if you feel well. Do not stop taking tenofovir without talking to your doctor. If you stop taking tenofovir even for a short time, or skip doses, the virus may become resistant to medications and may be harder to treat.

Ask your pharmacist or doctor for a copy of the manufacturer's information for the patient.

Before taking tenofovir,

• tell your doctor and pharmacist if you are allergic to tenofovir DF, tenofovir AF, any other medications, or any of the ingredients in tenofovir DF tablets or oral powder or tenofovir AF tablets. Ask your pharmacist for a list of the ingredients.

• tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking. Your doctor may need to change the doses of your medications or monitor you carefully for side effects.

• tell your doctor if you have or have ever had the conditions mentioned in the IMPORTANT WARNING section, bone problems including osteoporosis (a condition in which the bones become thin and weak and break easily) or bone fractures, or liver or kidney disease.

• tell your doctor if you have or ever had HIV. If you have HIV that is not being treated with medications and you take tenofovir, your HIV infection may become more difficult to treat. Your doctor may test you for HIV before you begin your treatment.

• tell your doctor if you are pregnant, plan to become pregnant, or are breastfeeding. If you become pregnant while taking tenofovir, call your doctor. You should not breastfeed if you are infected with HIV or if you are taking tenofovir.

• you should know that while you are taking medications to treat HIV infection, your immune system may get stronger and begin to fight other infections that were already in your body. This may cause you to develop symptoms of those infections. If you have new or worsening symptoms during your treatment with tenofovir, be sure to tell your doctor.

Unless your doctor tells you otherwise, continue your normal diet.

Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

Tenofovir may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

• diarrhea
• headache
• depression
• rash
• itching
• fever
• difficulty falling asleep or staying asleep
• gas, heartburn, or indigestion
• weight loss

Some side effects can be serious. If you experience any of those listed in the IMPORTANT WARNING or SPECIAL PRECAUTIONS sections, call your doctor immediately.

• decreased urination
• swelling of feet and ankles
• ongoing or worsening bone pain
• pain in the arms, hands, feet, or legs
• pain in upper right part of your stomach,
• dizziness or lightheadedness
• fast or irregular heartbeat
• shortness of breath or fast breathing
• cold or blue-colored hands and feet

Tenofovir DF and tenofovir AF may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom).

It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach. http://www.upandaway.org

Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA's Safe Disposal of Medicines website (http://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at https://www.poisonhelp.org/help. If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911.

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

Keep a supply of tenofovir DF and tenofovir AF on hand. Do not wait until you run out of medication to refill your prescription.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.