Tenofovir

Tenofovir is an oral medication, also known under the marketing name of Viread, which is prescribed by medical doctors in conjunction with other drugs to treat the HIV virus and the infections it causes.

Overview

What is Tenofovir?

Tenofovir is a medication available in oral tablet or oral powder form only by prescription from your doctor. While it doesn’t prevent or cure HIV nor does it cure or prevent AIDS, the drug does keep HIV from reproducing, which slows down its destruction of the immune system. Tenofovir is successful in delaying HIV or AIDS-related issues, but does not keep patients from spreading the virus on to others they expose. Tenofovir is effective in treating chronic hepatitis B viral infections in addition to HIV infection.

Tenofovir is in a class of drugs known as nucleoside reverse transcriptase inhibitors. It is also a hepatitis B virus reverse transcriptase inhibitor. Tenofovir works against both infections in the same way.

How does Tenofovir work?

Tenofovir works by blocking the effectiveness of reverse transcriptase, which is an enzyme that is required for HIV and hepatitis B to make copies and flourish. This blocking process is known as chain termination and it is death to the virus.

Blocking this reverse transcriptase process reduces the amount found in the body and increases CD4 cell count. CD4 cells are white blood cells that the body uses to fight infections. By using these two approaches, blocking the chain of reproduction and increasing the antibodies, Tenofovir is effective in preventing the virus from spreading.

What is the human immunodeficiency virus?

Human immunodeficiency virus, also known as HIV, is the virus that eventually causes AIDS which is known as acquired immunodeficiency syndrome. Patients with AIDS have a severely failed immune system, allowing a take-over by infections, cancers, and other medical crisis conditions, which eventually kills them. Infection with HIV occurs with the transfer of bodily fluids including blood, semen, vaginal fluids and breast milk.

Vital CD4 T cells are infected by HIV, among other cells critical to live, which leads to low levels of these cells, eventually causing the body to become more susceptible to infection over time. At the early stages, some people are unaware that they are infected with the HIV virus and can pass it on unknowingly. Early symptoms include:

  • Fever
  • Malaise
  • Arthralgia
  • Loss of appetite
  • Rash
  • Myalgia
  • Fever and rash
  • Pharngitis
  • Ulcers in the mouth
  • Loss of weight

If you exhibit any of these symptoms, it is advised that you get tested for HIV promptly as the earlier you are treated for the virus, the better chance you have of long-term survival. If you have been diagnosed with HIV, your doctor will advise you on preventive measures that you should take to keep from spreading it to other people.

Tenofovir stops the spread of the HIV virus and, in some cases, prevents it from becoming a full-blown AIDS infection in certain patients.

What is Hepatitis B?

Hepatitis B is a virus that infects the liver and has the following symptoms:

  • Loss of appetite
  • Nausea or vomiting
  • Extreme fatigue
  • Fever
  • Stomach pain
  • Jaundice

The patient experiences these symptoms for several weeks, taking months to get back to feeling normal again. Most patients with hepatitis B make a full recovery, but as many as 1 in 20 become carriers of the disease, infecting others while staying symptom-free themselves. Transmission to other people can occur through bodily fluids such as saliva, blood, semen and vaginal fluids.

Treatment of Hepatitis B with Tenofovir keeps the virus under control and prevents damage to the liver. Tenofovir does not keep patients diagnosed with hepatitis B from spreading the disease.

Conditions treated

  • HIV, hepatitis B

Type of medicine

  • Antiviral

Side effects

Tenofovir has been known to cause the following side effects:

  • Chest pain
  • Cough
  • Fever or chills
  • Tightness in the chest
  • Troubled breathing
  • Discomfort in the stomach or abdomen
  • Low appetite
  • Gasping or panting for breath
  • Uncomfortable feeling as a whole
  • Cramping or pain in muscles
  • Fatigue
  • Agitation
  • Diarrhea
  • Bone pain
  • Changes in urination
  • Confusion
  • Weak even when not exerting yourself
  • Convulsions or seizures
  • Depression
  • Fast heartbeat
  • Increased blood pressure
  • Increased thirst
  • Muscle twitching
  • Pains in the stomach, side, or abdomen, possibly radiating to the back
  • Stupor
  • Swelling of the face, fingers, or lower legs
  • Vomiting
  • Weight gain
  • Yellow eyes or skin

If you experience these side effects, check with your doctor immediately. As your body adjusts to Tenofovir treatment, side effects you are experiencing may go away or lessen. Your health care professional may be able to inform you about methods to reduce or prevent side effects.

If any of the following side effects continue or are severe, contact your physician immediately:

  • Back pain
  • Lack or loss of strength
  • Pain
  • Redness of the skin
  • Skin rash, itching skin, hives or welts
  • Burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings
  • Heartburn or indigestion
  • Joint pain or swelling
  • Muscle pains or stiffness
  • Passing of gas
  • Redistribution or accumulation of body fat
  • Weight loss

You may experience other side effects than those listed. Check with your doctor if you have any side effects that you feel are severe or prolonged in duration.

Dosage

Your doctor has determined your prescription of Tenofovir based on your particular health condition, age, weight, symptoms and other factors. Do not change the dosage, frequency or duration of your drug treatment from what your doctor has prescribed as this could affect how well the Tenofovir treatment works or even increase or worsen the side effects.

Tenofovir is part of a combination medication regimen, so it is important to take all of the medications prescribed to you at the time of day specified by your health care professional, as this will make the treatment regimen more effective.

Take Tenofovir for the entire duration prescribed even if you begin to feel better. Do not allow yourself to run out of medicine; contact your health care provider if you are running low.

Oral powder instructions

Patients using the oral powder form of Tenofovir need to follow these steps:

  • Measure using only the dosing scoop included with the Tenofovir prescription
  • Mix the oral powder with two to four ounces of soft food (applesauce, yogurt)
  • Swallow the Tenofovir immediately so it does not dissolve and taste bitter
  • Do not mix Tenofovir with liquid

HIV Patients

Oral powder and tablet dosage for HIV patients may be different from the average doses described. Each patient is different, so follow your prescribed dosage instructions.

Adults and children 12 years of age and older who weigh at least 35 kilograms will most likely be prescribed 300 milligrams once per day.

Children 2 to 11 years of age will have their dosage based on their body weight and determined by their doctor. On average, the dose is 8 milligrams per kilogram of body weight per day. The dose may be increased as required but doesn’t typically exceed 300 milligrams per day.

Children younger than 2 years of age will have their dose of Tenofovir determined by their doctor.

Hepatitis B patients

Adults and children 12 years of age who weigh at least 35 kilograms will typically be on a dose of 300 milligrams once per day for the treatment of chronic hepatitis B infection. Children younger than 12 years of age or who weigh less than 35 kilograms will have their dose determined by their health care provider.

If you miss a dose of Tenofovir, take it as soon as you remember unless it is almost time for the next dose; do not double dose, skip the missed dose and resume your dosing schedule as soon as possible.

Interactions

It is of critical importance that you disclose your full medical history as well as details of any drugs you are currently taking or have taken in the recent past before you begin a course of treatment with Tenofovir or any other drug. Be certain to include all prescription as well as non-prescription medications you may be taking and details of any vitamin, herbal or holistic supplements or treatments you are currently taking or have taken in the recent past.

If you have liver, kidney or bone conditions now or in the past, inform your doctor before being treated with Tenofovir. You should also inform your doctor if you are pregnant, planning to become pregnant or breastfeeding. Using hormone-based birth control such as the pill, implants or vaginal rings, these could cause complications with Tenofovir, so be sure to inform your healthcare provider about your use of these medications.

Studies on pediatric patients younger than 2 years of age that are infected with the HIV virus have not been performed to determine the effectiveness or safety of Tenofovir. Children 12 years of age and weighing less than 35 kilograms have not been studied for effectiveness or safety of Tenofovir in regard to treatment for hepatitis B. No problems have been observed for use of Tenofovir in geriatric patients; however, these patients may be more susceptible to age-related kidney, liver or heart problems that may affect the safe use of this drug.

Certain drugs will affect the use of Tenofovir by changing the way it works in the body or making it unsafe when used in combination. While you are being treated with Tenofovir, make sure your health care professional knows all prescription, non-prescription, vitamin, herbal and holistic drugs you are taking prior to treatment.

The following drugs are known to cause various issues when used with Tenofovir:

  • Atazanavir
  • Didanosine
  • Ledipasvir
  • Darunavir
  • Lopinavir
  • Ritonavir
  • Tipranavir

This is not a complete list; Tenofovir may interact with other drugs, so it is recommended that you discuss any other courses of treatment you are on with your health care provider prior to treatment with Tenofovir.

Other medical problems may affect the effectiveness and safety of a course of treatment with Tenofovir. If you have any of the following conditions, make sure your health care provider is informed:

  • Bone problems including fractures
  • Fanconi syndrome
  • Kidney failure
  • Liver disease
  • Osteomalacia
  • Osteoporosis
  • Kidney disease requiring dialysis

Use of Tenofovir with some of these conditions could make them worse or increase the effects of the drug due to slow removal from the body. Use of Tenofovir with these conditions should be under close cautionary doctor’s advice.

Warnings

Your doctor will check the progress of your condition on a regular basis while you are being given a course of treatment that includes Tenofovir. Blood and urine tests will be part of these progress checks, which will require office visits.

If you are also using adefovir, Atripla, Complera, Hepsera, Stribid or Truvada, inform your doctor right away. Your doctor may delay the start of your Tenofovir treatment if you are using these drug therapies.

Two serious reactions have been reported in patients on a course of treatment with Tenofovir: lactic acidosis, which is a build-up of acid in the blood and liver toxicity, including enlarged liver. These conditions, in reaction to Tenofovir, are more common in female patients, overweight patients or patients who have been on anti-HIV drug treatment for an extended period of time. If you experience symptoms of stomach discomfort or cramping, nausea, vomiting, diarrhea, decreased appetite, general discomfort, muscle cramping or pain, fatigue, weakness, trouble breathing or yellow skin or eyes, contact your doctor immediately.

It is important not to change your dosage of Tenofovir including not skipping doses or stopping the treatment for the duration of the treatment regimen without your physician’s permission.

Tenofovir may increase your risk of broken bones; take measures to avoid situations where broken bones are a risk.

Tenofovir may put patients at risk for kidney injury, so make certain that you keep appointments for all blood tests that are scheduled by your doctor and avoid other medications that may have an adverse effect on your kidneys such as other antiviral medications or NSAID pain medicines.

Your immune system, while on Tenofovir, may be stronger and you may notice new symptoms of hidden conditions while you are on the drug regimen. If you have hidden disorders or infections such as Graves’ disease, Guillain-Barre syndrome, polymyositis, pneumonia or tuberculosis and notice new symptoms, contact your doctor right away.

Tenofovir may cause your body to store excess fat; if you notice changes in your body shape in your upper back and neck or around the chest and stomach area, contact your doctor. You may also notice a loss of fat in your arms, legs or face.

Tenofovir does not decrease the risk you have of transmitting HIV or Hepatitis B to others either by sexual contact or by blood contamination. If you are infected, it is recommended that you avoid any sexual activity that involves an exchange of body fluids with others. If you do have sex, always wear or have your partner wear a condom made of latex or polyurethane. Do not re-use or share needles or medical equipment with anyone. Any questions about transmitting the virus, sexual contact or blood contact should be discussed with your healthcare professional.

Unless your doctor has prescribed it specifically, do not take other medicines in conjunction with Tenofovir.

You should also inform your doctor if you are pregnant, planning to become pregnant or breastfeeding. Using hormone-based birth control such as the pill, implants or vaginal rings could cause complications with Tenofovir, so be sure to inform your health care provider about your use of these medications.

Storage

Store Tenofovir and other medications out of sight and reach of children. Keep it in the original container at room temperature and do not allow it to come in contact with excessive heat, moisture or direct light. Do not allow Tenofovir to freeze.

Summary

Tenofovir is an oral medication available that is prescribed in conjunction with other drugs to treat patients infected with HIV, the viral infection that causes AIDS, or hepatitis B. Tenofovir works by stopping the ability of the HIV or hepatitis B virus to clone itself and multiply, effectively reducing the amount of the virus in the body. Tenofovir also increases CD4 cells, which also fight off the HIV and hepatitis B virus.

Patients on drug therapy regimens that include Tenofovir may experience flu-like side effects such as cough, fever or chills, nausea and tiredness or weakness. They may also feel generally ill or uncomfortable or have a decreased appetite or depression. If the patient feels that these symptoms are severe or are lasting for a long duration, they should contact their doctor right away.

Patients who have a history of kidney or liver problems or who are pregnant or are breastfeeding should proceed with use of Tenofovir with caution. Tenofovir is not recommended for the treatment of HIV infection in children under two years old; nor is it recommended for treatment in children with hepatitis B infected children younger than 12.

Use of Adefovir, Atripla, Complera, Hepsera, Stribild or Truvada during treatment with Tenofovir is not recommended. All medications, whether they are prescription, non-prescription, vitamin, herbal or holistic in nature should be discussed with your healthcare provider for effectiveness and safety while on treatment with Tenofovir.

Severe reactions know to be caused by Tenofovir include lactic acidosis and liver toxicity. For this reason, symptoms of stomach discomfort, cramping, nausea, vomiting, diarrhea, decreased appetite, tiredness or weakness or trouble breathing, yellow skin or eyes should be reported to your doctor immediately.

Dosage depends on the age and weight of the patient as well as other factors as determined by your healthcare provider. Average doses are 300 milligrams once per day for those older than 12 weighing more than 35 kilograms. Powdered forms for Tenofovir should be mixed with soft foods, never liquids, and consumed immediately, not allowing the powder to dissolve, which will give a bitter taste. Dosage size, frequency, and duration should not be changed nor should the recommended time of day to take Tenofovir, as these details are important to the effectiveness of the drug in combating the virus.

 

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Last Reviewed:
December 23, 2017
Last Updated:
December 22, 2017
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