All You Should Know About Tenofovir Doses

When it comes to finding the most used and highly effective and tolerable med for combating various serious health infections, including – HIV, HBV, and more; then tenofovir is always the first on the list. It’s a drug that works with other meds to fully combat these body viruses for a healthier and longer life.

Tenofovir is not always used alone in treating a body illness; it’s primarily used in combinations with other medicines to treat those conditions effectively. It belongs to a class of NRTIs known to combat HIV, HBV as well as occupational exposure and nonoccupational exposure.

HIVPrEP is an informational site about HIV, hepatitis, PEP as well as PrEP. Here is the full info about TDF available dose, treatments/dosage information as well as drug precautions and other helpful information to safely administer tenofovir to combat the body viruses for a healthier life.

✔Available Doses of Tenofovir

There are various medicines used in combination with tenofovir. Mostly, tenofovir dosages are available in meds used for HIV, chronic hep B, occupational and nonoccupational exposure. It’s used as an NRTIs.

Apart from being a generic, tenofovir is available as Viread as a brand name. Since it’s used to treat various health conditions, its dosage is differently formulated in addition to other medicines for that particular condition.

For example, there is varying dosage information regarding this med depending on patient health. A doctor may adjust the dosage depending on your renal and liver function as well as precautions dialysis.

🎗HIV Treatment Dose

TDF is a potent antiretroviral drug used in combination with other meds to effectively combat HIV/AIDS in the body. It’s a one-day pill administered as directed by the medical specialist.

Sold under the brand-name Viread, it is co-formulated with other meds under the following names to fully combat HIV virus:

  • Truvada (having TDF/FTC) – used with another third med to make it a complete regimen for HIV/AIDS treatment;
  • Atripla – contains TDF/FTC and efavirenz in one pill;
  • Complera – consist of TDF/FTC/rilpivirine as a fixed-dose tablet;
  • Stribild – composed of TDF/FTC/cobicistat/elvitegravir available as a fixed-dose med for HIV treatment.

There are other meds (usually nukes and sometimes protease inhibitors) combinations that are used together with tenofovir in treating this virus in the body [1].

Primarily, tenofovir as an anti-HIV remedy, targets and interferes with the virus enzyme called reverse transcriptase which is uniquely used by the HIV-infected cells to make/produce new viruses in the white blood cells.

The action of this med is to take control of this enzyme (inside the infected cell) and terminate its action thus limiting or lowering the production of new viruses in the body.

Continual administering this med exactly as prescribed eventually overcome the actions of the virus decreasing its viral load and increasing the CD4 cell count resulting in a better and stronger immune system. The immune system depends on the T-cells or CD4 count. The more T-cells, the stronger the immune function.

TDF may be accompanied by side effects and interactions like any other med. That is why it’s necessary to let a medical specialist assess your health before prescribing you anti-HIV med.

Depending on the outcome of your health, the right prescription should be administered with necessary drug adjustment to ensure safe dosage and general wellness of the body.

💊Tenofovir Dose for Hepatitis B

Tenofovir is a highly effective antiviral drug compared to some meds (such as adefovir and lamivudine) in the treatment of chronic hep B. It’s available as a 300 mg once a day tablet which can be taken with or without meals.

In some instances, depending on the patient’s kidney function, this dose can be adjusted (usually to lower dosages) in response to how the patient kidney works.

Hep B is a serious noncytopathic virus – meaning it does not damage the liver by itself but rather as it multiplies in the body and increase in number, the immune system mounts an assault on the virus causing damage to the liver in the form of inflammation and other effects.

Being an NRTIs, tenofovir is a highly potent drug that targets and prevent the HBV virus from increasing in the body, usually by reducing its viral load making the immune system regain its functionality.

This drug does not cure hep B but rather reduce its amount in the body. It may not prevent complications of other illnesses such as liver cancer as well as cirrhosis of the liver. Furthermore, tenofovir cannot prevent the spread of the HBV virus to others. Nonetheless, TDF is a safe and highly-effective long-term medical remedy for HBV administered to patients 12 years of age and above.

Occupational Exposure

Occupational exposure is a health condition where the exposure to the virus or infection is contracted by contact with a potentially harmful virus agent (or infection) as a result of individual job duties or one’s work. Exposed to HIV or another infectious agent may be through contact with a mucous membrane, needlestick injury, contact of skin with blood or other body fluids which may be harmful and pose a potential risk to the virus infection.

When a patient is occupationally exposed to the virus – especially HIV, tenofovir with emtricitabine (TDF/FTC) and another third NRTIs drug (like rilpivirine) is used as a PEP to target and kills the virus from entering the blood cells. Do not administer TDF/FTC alone as PEP. It does not work effectively and it may cause the virus to be resistant to other medications in combinations with tenofovir [2].

Note that once the infection enters the blood cells, it’s very hard to terminate its replication chain or completely remove the virus from the infected cells. That is why PEP is administered as early as possible (usually within 72 hours – the earlier the better after exposure) to fight the virus before it comes into contact with the blood (or T-cells).

Non-Occupational Post-Exposure Prophylaxis

This is also known as nPEP. Like the occupational exposure, nPEP is a short-term treatment administered immediately when an individual has been at a high-risk of nPEP exposure to an infectious agent/virus that occurs outside of his/her work or job duties. For example; HIV, hep B virus, among other transmittable blood or fluid infections.

This can be during sex or exposure to needles to inject meds. The ultimate aim of this therapy is to reduce/lower the risk of virus infection before the virus gains control after inhibiting the T-cells or CD4 cells.

Tenofovir is known to have a higher positive safer profile in fully managing the exposure by effectively targeting the virus at its early stage and kills it before it reaches the blood.

To fully accomplish this, TDF + FTC and another med must be used. Do not administer TDF alone as it cannot work as intended and might cause the virus to gain access to the blood cells as HIV.

Like occupational exposure therapy, nPEP is administered in less than 72 hours (earlier the better) and a regime of 28 days is prescribed by a doctor.

In this period, it’s necessary to fully follow the prescription to attain better results otherwise an individual poses a risk of attracting the virus rendering the nPEP useless and causing other risk factors such as virus drug-resistant to tenofovir medication.

🎚Drug Dose Adjustments

TDF is available in various dose strengths [3]. The most commonly used dosage is 300 mg tab taken daily with or without a meal. The availability of different dosages is to address the patient response to medication (in terms of efficacy and tolerability) based on their health illnesses – particularly the kidney.

Other illnesses that need dose adjustment are renal conditions and liver disorders. Pregnancy also may need a close examination to dose adjustment. HBV may need varying dosage based on patient weight.

To address the major side effects associated with TDF, Gilead Sciences formulate a prodrug of tenofovir DF known as tenofovir alafenamide (or TAF). TAF is a highly potent drug than TDF with better tolerability and works well with the patient having renal and BMD problems [4].

It’s the ideal replacement of TDF and more pharmaceuticals are beginning to replace TDF with TAF for better tolerability and safety. Both TAF and TDF have the same efficacy – in terms of viral load suppression.

🤰Tenofovir and Pregnancy

Although the information on TDF usage during pregnancy is limited, TDF might be safe to be used during this period but safety is not fully guaranteed. Administration of this med may lead to adverse events of which most are mild to moderate and not necessarily to be TDF-related [5].

In utero tenofovir-exposed infants, it shows that there is no high risk of growth or bone abnormalities and there is no indication in increased or higher congenital anomaly risk while using TDF drug combinations.

With these results, TDF is safe for use in the treatment of HIV/HBV virus in infected pregnant women. The effects of tenofovir on bone health and growth of infants is narrow or limited and more research and investigation are needed.

There is not enough safety data on TDF administration in pregnancy and special considerations should be performed to ensure safety on maternal and fetal health. The use of TAF as a combination therapy seems to work better.

Renal Failure

Tenofovir high antiviral performance as well as preferred or favorable metabolic profile favors most patients undergoing HIV prevention and treatment as well as HBV. Not all patients respond well to TDF use especially if the individual has kidney problems [6].

This med is known to demonstrate a tubular toxicity risk, especially to patients with low body weight as well as conditions associated with diabetes mellitus. Long-term use of this med may lead to a decreased GFR (normal kidney GFR number is 90 or higher although a GFR around 60 – 89 is counted normal for some individuals depending on their age) to some patients while others may never experience this problem with long exposure to TDF treatment.

Being the only available and recommended NRTI drug, its safety concern on renal is still ambiguous. Nonetheless, TAF is a highly tolerable prodrug of tenofovir DF which is an improved version with a better safety to patient renal and BMD.

With TDF, from another study, there is a slight but significant decrease in kidney function, especially with long-term use of this med while other studies shown this med to be safe with kidney functions. With these synonymous studies, TDF-treated patients might experience a medium to a high reduction in estimated CrCl (creatinine clearance) – usually at 0.4 ml/min per year or rapid decline of >3 ml/min per year.

With varying rates of decline in kidney function based on various clinical studies, these effects still boundaries of normal function to most patients. Tenofovir alafenamide is usually recommended to ensure safety to kidney function.

If a patient has this condition, dosage adjustment is considered based on the patient’s estimated CrCl [7].

A patient with CrCl of at least:

  • 15 mL/min, there is no needed TAF adjustment;
  • 50 mL/min, no TDF adjustment needed;
  • 30–49 mL/min, administer 300 mg TDF taken every 48 hours;
  • 10–29 mL/min, administer 300 mg TDF taken every 72 – 96 hours.

There is no data on individuals with CrCl not more than 10 mL/min (or non-hemodialysis).

Another safe and effective dose for patients with renal impairment is to use the lower dose of tenofovir 150 mg daily. Other dosages of 150, 200, and 250 mg have been approved to be administered to patients with renal failure. A doctor can assess the condition of your CrCl and adjust the medication appropriately.

TAF is the newest recommended drug combination as it profiles shows better effects on renal function and BMD than TDF. TAF is non-inferior to TDF.

Liver Disorders

Although there is no available TDF adjustment recommended for liver disorders, TDF is linked with a higher risk of an end-stage liver problem (or ESLD) and hepatocellular carcinoma, especially among individuals living with HBV, HCV as well as HIV.

The liver disease remains a major cause of being illnesses or unhealthiness and mortality affecting less than 1% of individuals with HIV/AIDS as well as hep B and C (which is known to play a role in inciting & inflaming liver injury). There is little information on recovery from TDF-related liver disorders/injury.

While using this drug, close monitoring and assessment of liver fibrosis levels should be carried out to ensure the safety of the liver while treating HIV, HBV or HCV with tenofovir.

Kidney Disease (Dialysis)

As part of ensuring safety to the kidney function, a doctor can adjust medication during kidney dialysis. In this regard, tenofovir alafenamide is usually recommended as a replacement to tenofovir DF [8].

Dose adjustment is done as follows:

With TAF:

  • there is no tablet adjustment recommended for patients having an estimated CrCl of <15 mL/min who are receiving or having chronic hemodialysis.

With tenofovir DF adults:

  • for those undergoing hemodialysis, a 300 mg tab is taken every 7 days. Administer only after the completion of hemodialysis dialysis;
  • for patients experiencing peritoneal dialysis, there is no available data and extra care with the help of a doctor is necessary.

A doctor should give you the right prescription during this process to ensure the safety of the kidneys while treating the virus.

How to Adjust the Right Tenofovir Dose?

There are various remedies used to treat HIV as well as hepatitis. As to which drug works better than the other depends on your health illnesses and the state of the virus infection.

TDF has been the only approved drug regimen used in combination with other meds. TAF may be a better alternative to TDF but not all highly effective meds have this composition.

If you think you have been exposed to HIV, Truvada (consisting of TDF/FTC) is still the best drug used in addition with another nuke or NRTIs med. Tenofovir/emtricitabine is also recommended as PrEP.

As a treatment of HIV/AIDS and hep B infection, tenofovir still works with better tolerability to the majority of the patients. Risk and safety concern with this drug is often associated with individuals having liver, kidney and BMD problems. This is addressed with TAF.

It’s always necessary to let a medical specialist assess your health and determine which medication and dosage is right for you. If you experience the aforementioned health conditions, do not stop TDF but let your doctor prescribe suitable dose adjustment while monitoring how it responds to the illness.

📚References:

  1. HIV Drug Chart. Poz.com.
  2. HIV PEP with emtricitabine/tenofovir/rilpivirine has excellent completion and adherence rates. Michael Carter 17 July 2015. Aidsmap.com.
  3. Tenofovir Dosage. Drugs.com.
  4. TAF vs. TDF (original tenofovir)—improvements in safety. Catie.ca. Retrieved October/November 2015.
  5. Safety of Tenofovir During Pregnancy for the Mother and Fetus: A Systematic Review. Liming Wang, Athena P. Kourtis, Sascha Ellington, Jennifer Legardy-Williams, Marc Bulterys. Clinical Infectious Diseases, Volume 57, Issue 12, 15 December 2013, Pages 1773–1781. Academic.oup.com. Published 17 September 2013.
  6. Tenofovir Effect on the Kidneys of HIV-Infected Patients: A Double-Edged Sword? Jérôme Tourret, Gilbert Deray, and Corinne Isnard-Bagnis. Ncbi.nlm.nih.gov. Published online 2013 Sep 19.
  7. Tenofovir Dosage. Renal Dose Adjustments. Drugs.com.
  8. Tenofovir Dosage. Dialysis. Drugs.com.
Logan Morris

Expert in pharmaceutical practice and antiviral medicine, founder of HIVPrEP. Main goal is to popularize HIV topics and create awareness for global masses on how to prevent the disease and how to use HIV medication safely.

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