Tenofovir

Tenofovir is a prescription medication used along with other medications to treat human immunodeficiency virus (HIV) and hepatitis B infections. Tenofovir belongs to a group of drugs called nucleoside reverse transcriptase inhibitors (NRTIs) which work by stopping the virus from replicating.

This medication comes in tablet form and in an oral powder to be mixed with soft food that does not require chewing (applesauce). Tenofovir is taken once daily. Tenofovir tablets can be taken with or without food.

Common side effects of tenofovir include nausea, rash, and diarrhea.

Tenofovir is a prescription medicine used:

• with other antiviral medicines to treat Human Immunodeficiency Virus (HIV) in adults and children 2 years of age and older. 
• to treat chronic hepatitis B virus (HBV) in adults. Tenofovir will not cure HBV.

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

Tenofovir may be found in some form under the following brand names:

• Viread

Tenofovir may cause serious side effects. See "Drug Precautions" section.

The most common side effects in all people who take tenofovir are:

• nausea
• rash
• diarrhea
• headache
• pain
• depression
• weakness

In some people with advanced HBV-infection, other common side effects may include:

• sleeping problems
• itching
• vomiting
• dizziness
• fever

Tell your healthcare provider if you have any side effect that bothers you or that does not go away.

These are not all the possible side effects of tenofovir. For more information, ask your healthcare provider or pharmacist.

Tell your healthcare provider about all the medicines you take, including prescription and non-prescription medicines, vitamins and herbal supplements. Tenofovir may affect the way other medicines work, and other medicines may affect how tenofovir works.

Do not take tenofovir if you also take:

• other medicines that contain tenofovir (Atripla, Complera, Truvada)
• adefovir (Hepsera)

Especially tell your healthcare provider if you take the following medications, as the dose of these other medications may need to be changed:

• didanosine (Videx)
• atazanavir (Reyataz)
• lopinavir with ritonavir (Kaletra)

Tenofovir can cause serious side effects, including:

1.  Build-up of an acid in your blood (lactic acidosis). Lactic acidosis can happen in some people who take tenofovir. Lactic acidosis is a serious medical emergency that can lead to death.

Lactic acidosis can be hard to identify early, because the symptoms could seem like symptoms of other health problems. Call your healthcare provider right away if you get the following symptoms which could be signs of lactic acidosis:

• feeling very weak or tired
• have unusual (not normal) muscle pain
• have trouble breathing
• have stomach pain with
  • nausea (feel sick to your stomach)
  • vomiting
• feel cold, especially in your arms and legs
• feel dizzy or lightheaded
• have a fast or irregular heartbeat

2.  Severe liver problems. Severe liver problems can happen in people who take tenofovir. In some cases these liver problems can lead to death. Your liver may become large (hepatomegaly) and you may develop fat in your liver (steatosis) when you take tenofovir.

Call your healthcare provider right away if you have any of the following symptoms of liver problems:

• Your skin or the white part of your eyes turns yellow (jaundice).
• dark "tea-colored" urine
• light-colored bowel movements (stools)
• loss of appetite for several days or longer
• nausea
• stomach pain

You may be more likely to get lactic acidosis or severe liver problems if you are female, very overweight (obese), or have been taking tenofovir for a long time.

• New or worse kidney problems can happen in some people who take tenofovir. If you have had kidney problems in the past or need to take another medicine that can cause kidney problems, your healthcare provider may need to do blood tests to check your kidneys during your treatment with tenofovir.
• Bone problems can happen in some people who take tenofovir. Bone problems include bone pain, softening or thinning (which may lead to fractures). Your healthcare provider may need to do additional tests to check your bones.
• Changes in body fat can happen in some people who take antiviral medicines. These changes may include increased amount of fat in the upper back and neck ("buffalo hump"), breast, and around the main part of your body (trunk). Loss of fat from the legs, arms, and face may also happen. The cause and long-term health effects of these conditions are not known.
• Changes in your immune system (Immune Reconstitution Syndrome) can happen when you start taking HIV medicines. Your immune system may get stronger and begin to fight infections that have been hidden in your body for a long time. Tell your healthcare provider if you start having new symptoms after starting your HIV medicine.

3.  Worsening of your Hepatitis B infection. Your hepatitis B Virus (HBV) infection may become worse (flare-up) if you take Viread and then stop it. A "flare-up" is when your HBV infection suddenly returns in a worse way than before.

• Do not let your tenofovir run out. Refill your prescription or talk to your healthcare provider before your tenofovir is all gone.
• Do not stop taking tenofovir without first talking to your healthcare provider.
• If you stop taking tenofovir, your healthcare provider will need to check your health often and do blood tests regularly to check your HBV infection. Tell your healthcare provider about any new or unusual symptoms you may have after you stop taking tenofovir. 
• Talk to your doctor about taking an HIV test before starting treatment with tenofovir for chronic hepatitis B. You should also get a test for HBV if you are taking tenofovir for treatment of HIV.

 

Medicines can interact with certain foods. In some cases, this may be harmful and your doctor may advise you to avoid certain foods. In the case of tenofovir, there are no specific foods that you must exclude from your diet when receiving tenofovir.

Before you take tenofovir, tell your healthcare provider if you:

• have liver problems, including hepatitis B (HBV) infection
• have kidney problems
• have bone problems
• have any other medical conditions, including HIV infection
• are pregnant or plan to become pregnant. It is not known if tenofovir will harm your unborn baby.

Tell your healthcare provider about all the medicines you take, including prescription and non-prescription medicines, vitamins and herbal supplements. Tenofovir may affect the way other medicines work, and other medicines may affect how tenofovir works.

Tell your doctor if you are pregnant or plan to become pregnant.

The FDA categorizes medications based on safety for use during pregnancy. Five categories - A, B, C, D, and X, are used to classify the possible risks to an unborn baby when a medication is taken during pregnancy.

This medication falls into category B. It is not known if tenofovir will harm your unborn baby. There is a pregnancy registry for women who take antiviral medicines during pregnancy. Its purpose is to collect information about the health of you and your baby. Talk to your healthcare provider about how you can take part in this registry.

Do not breastfeed if you are taking tenofovir. Tenofovir passes into your breast milk. You should not breastfeed because of the risk of passing HIV to your baby. Talk to your healthcare provider about the best way to feed your baby.

• Take tenofovir exactly as your healthcare provider tells you to take it.
• Take tenofovir at the same time every day.
• For adults: the usual dose of tenofovir is one 300 mg tablet each day. If you have kidney problems, your healthcare provider may tell you to take tenofovir less often.
• Adults who are unable to swallow tenofovir tablets whole may take 7½ scoops of tenofovir oral powder.
• For children 2 years of age and older, your healthcare provider will prescribe the right dose of tenofovir oral powder or tablets based on your child's body weight.
• Tell your healthcare provider if your child has problems with swallowing tablets.
• Take tenofovir tablets by mouth, with or without food.
• Do not miss a dose of tenofovir. If you miss a dose of tenofovir, take the missed dose as soon as you remember. If it is almost time for your next dose of tenofovir, do not take the missed dose. Take the next dose of tenofovir at your regular time.
• If you take too much tenofovir, call your local poison control center or go right away to the nearest hospital emergency room.

Preparation of tenofovir powder:

1. Wash and dry your hands.
2. Measure ¼ to ½ cup of soft food into a cup or bowl.
3. To open a new bottle of powder, press down on the bottle lid and turn to remove (see picture on the top of the bottle cap). Peel off the foil.
4. Measure the number of scoops prescribed by your healthcare provider.
   • For each full scoop prescribed:
     • Fill the dosing scoop to the top.
     • Use the flat edge of clean knife to make the powder even with the top of the scoop 
   • For ½ scoop:
     • Fill the dosing scoop up to the "½ line" on the side
5. Sprinkle the tenofovir oral powder on the soft food. Stir with a spoon until well mixed. Give the entire dose right away after mixing to avoid a bad taste.
6. Close the bottle of tenofovir tightly.
7. Wash and dry the dosing scoop. Do not store the dosing scoop in the bottle.

Take tenofovir exactly as prescribed by your doctor. Follow the directions on your prescription label carefully.

Recommended Dose in Adults

If you take too much tenofovir, call your healthcare provider or local Poison Control Center, or seek emergency medical attention right away.

If tenofovir is administered by a healthcare provider in a medical setting, it is unlikely that an overdose will occur. However, if overdose is suspected, seek emergency medical attention.

• Store tenofovir tablets or oral powder at 59 °F to 86 °F (15 °C to 30 °C).
• Keep tenofovir in the original container.
• Do not use tenofovir if the seal over the bottle opening is broken or missing.
• Keep the bottle tightly closed.
• Keep tenofovir and all medicines out of the reach of children.

WARNINGS: LACTIC ACIDOSIS/SEVERE HEPATOMEGALY WITH STEATOSIS and POST TREATMENT EXACERBATION OF HEPATITIS

Lactic acidosis and severe hepatomegaly with steatosis, including fatal cases, have been reported with the use of nucleoside analogs, including tenofovir, in combination with other antiretrovirals.

Severe acute exacerbations of hepatitis have been reported in HBV-infected patients who have discontinued anti-hepatitis B therapy, including tenofovir. Hepatic function should be monitored closely with both clinical and laboratory follow-up for at least several months in patients who discontinue anti-hepatitis B therapy, including tenofovir. If appropriate, resumption of anti-hepatitis B therapy may be warranted.