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Medical Disclaimer: This information is for educational purposes only and is not a substitute for professional medical advice.
Tenofovir Disoproxil Fumarate
Brand Name
Viread
Generic Name
Tenofovir Disoproxil Fumarate
Active Ingredient
Tenofovir DisoproxilCategory
Hepatitis B Virus Nucleoside Analog Reverse Transcriptase Inhibitor [EPC]
Salt Form
Fumarate
Variants
5
Different strengths and dosage forms
| Strength | Form | Route | NDC |
|---|---|---|---|
| 150 mg/1 | TABLET, COATED | ORAL | 61958-0404 |
| 200 mg/1 | TABLET, COATED | ORAL | 61958-0405 |
| 300 mg/1 | TABLET, COATED | ORAL | 61958-0401 |
This page is for informational purposes only and does not replace medical advice. Before using any prescription or over-the-counter medication for Viread, you must consult a qualified healthcare professional.
| 250 mg/1 | TABLET, COATED | ORAL | 61958-0406 |
| 40 mg/g | POWDER | ORAL | 61958-0403 |
Detailed information about Viread
Tenofovir disoproxil is a potent nucleotide reverse transcriptase inhibitor (NRTI) used to manage HIV-1 infection and chronic hepatitis B virus (HBV) by blocking viral replication.
For the majority of adult patients with normal kidney function, the standard dose of tenofovir disoproxil fumarate is 300 mg taken once daily. This dosage applies to both the treatment of HIV-1 infection and chronic Hepatitis B. When used for HIV-1, it must be part of a multi-drug regimen to ensure the virus does not develop resistance. When used for PrEP, the 300 mg dose is taken daily in combination with emtricitabine 200 mg.
Pediatric dosing is strictly based on the child's body weight to ensure safety and efficacy. For children aged 2 years and older:
For children who cannot swallow tablets, the oral powder may be prescribed, with dosing calculated by the healthcare provider at approximately 8 mg per kilogram of body weight, up to a maximum of 300 mg.
Since tenofovir is primarily cleared by the kidneys, patients with reduced kidney function (measured by Creatinine Clearance, or CrCl) require adjusted dosing intervals to prevent drug buildup and toxicity:
No dosage adjustment is typically required for patients with liver impairment. However, patients with advanced liver disease (cirrhosis) should be monitored closely for potential complications during treatment.
Clinical trials did not include sufficient numbers of subjects aged 65 and over to determine if they respond differently than younger subjects. Healthcare providers generally start at the lower end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function in this population.
Tenofovir disoproxil should be taken exactly as prescribed by your doctor. The following guidelines are standard:
If you miss a dose, take it as soon as you remember. However, if it is almost time for your next scheduled dose, skip the missed dose and resume your regular schedule. Do not take two doses at once to make up for a missed one. Maintaining consistent levels is crucial for preventing viral resistance.
In the event of an overdose, contact a poison control center or seek emergency medical attention immediately. Symptoms of overdose are not well-documented but may include severe gastrointestinal distress or exaggerated side effects. Tenofovir can be efficiently removed by hemodialysis (approximately 10% extraction over a 4-hour session).
> Important: Follow your healthcare provider's dosing instructions exactly. Do not adjust your dose or stop taking the medication without medical guidance, as this can lead to a sudden 'flare-up' of Hepatitis B or the development of HIV resistance.
Most patients tolerate tenofovir disoproxil well, but some may experience 'start-up' symptoms that often resolve after the first few weeks of treatment. Common side effects include:
Tenofovir disoproxil is a potent medication that requires careful medical supervision. It is not a cure for HIV or Hepatitis B, but it helps manage the conditions. Patients must be aware that they can still transmit HIV or HBV to others through blood or sexual contact while taking this medication, although the risk is significantly reduced when the viral load is undetectable.
As mandated by the FDA, the following warnings are prominently displayed on the prescribing information:
Certain drugs should never be used with tenofovir disoproxil because they can cause dangerous reactions or significantly reduce the effectiveness of the treatment:
Tenofovir disoproxil must NEVER be used in the following circumstances:
These are conditions where the drug should only be used if the benefits clearly outweigh the risks, under intense medical supervision:
Tenofovir disoproxil is generally considered one of the safer antiretrovirals during pregnancy. Under the older FDA system, it was classified as Category B. Data from the Antiretroviral Pregnancy Registry (APR) has monitored thousands of women taking tenofovir and has found no increase in the risk of major birth defects compared to the general population.
Tenofovir disoproxil is an acyclic nucleoside phosphonate diester analog of adenosine monophosphate. At the molecular level, it follows a specific path to efficacy:
Common questions about Viread
Tenofovir disoproxil is a powerful antiviral medication primarily used to treat two major viral infections: Human Immunodeficiency Virus type 1 (HIV-1) and chronic Hepatitis B Virus (HBV). For HIV, it is always used as part of a combination therapy to lower the amount of virus in the body and help the immune system recover. For Hepatitis B, it can be used on its own to stop the virus from replicating and prevent long-term liver damage. Additionally, it is used in combination with emtricitabine for Pre-Exposure Prophylaxis (PrEP) to prevent HIV infection in high-risk individuals. It works by blocking an enzyme the viruses need to copy their DNA, effectively stopping them from spreading.
The most common side effects reported by patients taking tenofovir disoproxil include nausea, diarrhea, headache, and a general feeling of weakness or fatigue. Some people also experience dizziness, depression, or trouble sleeping when they first start the medication. These symptoms are often mild and may improve as the body adjusts to the drug over the first few weeks. However, more serious side effects can occur, such as kidney problems or a decrease in bone mineral density. It is important to report any persistent or worsening symptoms to your healthcare provider immediately to ensure the medication is not causing internal damage.
There is no known direct chemical interaction between tenofovir disoproxil and alcohol that makes the drug ineffective. However, healthcare providers generally advise moderation or avoidance of alcohol because both alcohol and tenofovir can put stress on the liver and kidneys. Chronic or heavy alcohol use increases the risk of liver inflammation and pancreatitis, which are also potential rare side effects of tenofovir. Furthermore, alcohol can interfere with your ability to take your medication consistently at the same time every day. Discussing your alcohol consumption with your doctor is important for the overall management of HIV or Hepatitis B.
Tenofovir disoproxil is considered one of the preferred antiviral medications for use during pregnancy. Extensive data from the Antiretroviral Pregnancy Registry shows no increased risk of birth defects in babies born to women who took tenofovir compared to the general population. It is frequently prescribed to pregnant women with HIV to prevent the virus from passing to the baby and to women with high levels of Hepatitis B to reduce the risk of transmission during birth. While generally safe, pregnant women will be monitored closely for kidney function and other potential side effects. Always consult your obstetrician and infectious disease specialist when managing these conditions during pregnancy.
Tenofovir disoproxil begins to inhibit viral replication within hours of the first dose, but it takes time to see a significant drop in the 'viral load' (the amount of virus in the blood). For most patients, a significant reduction in viral levels is seen within 2 to 4 weeks of starting treatment. Achieving an 'undetectable' viral load—where the virus is at such low levels it cannot be measured by standard tests—can take anywhere from 3 to 6 months of consistent daily use. The exact timeframe depends on the individual's initial viral load and how well they adhere to their medication schedule. Regular blood tests are necessary to track this progress.
No, you should never stop taking tenofovir disoproxil suddenly without your doctor's explicit instruction. This is especially dangerous for patients with Hepatitis B, as stopping the drug can cause a 'rebound' effect where the virus becomes highly active again, leading to severe liver inflammation or liver failure. For HIV patients, stopping the medication allows the virus to start replicating again, which can lead to drug resistance and a weakened immune system. If you need to stop the medication for a medical reason, your doctor will provide a plan to monitor your health closely during the transition. Always ensure you have an adequate supply of the medication so you do not run out.
If you miss a dose of tenofovir disoproxil, you should take it as soon as you remember. If it is already close to the time for your next scheduled dose, skip the missed dose and simply take your next one at the regular time. Do not take two doses at once to 'catch up,' as this increases the risk of side effects without providing extra benefit. Consistency is vital in antiviral therapy; missing doses frequently can allow the virus to develop resistance, making the drug less effective in the future. Using a pillbox or a phone alarm can be a helpful way to remember your daily dose.
Weight gain is not a commonly reported direct side effect of tenofovir disoproxil (TDF) itself. In fact, some studies suggest that TDF may be associated with lower weight gain or even slight weight loss compared to newer drugs like Tenofovir Alafenamide (TAF) or certain integrase inhibitors. However, many patients starting HIV treatment experience 'return-to-health' weight gain as their immune system recovers and their body begins to process nutrients more effectively. If you notice significant or rapid weight changes, it is best to discuss them with your healthcare provider to determine if they are related to the medication, lifestyle changes, or other underlying health conditions.
Tenofovir disoproxil can be taken with many other medications, but it does have several important interactions. It should not be taken with other drugs that can damage the kidneys, such as high-dose NSAIDs (like ibuprofen) or certain antibiotics. It also interacts with some other HIV medications, like didanosine or atazanavir, requiring dose adjustments or close monitoring. Because tenofovir is not processed by the liver's primary enzyme system (CYP450), it has fewer interactions than many other antivirals, but a full review of your medication list by a pharmacist or doctor is still essential. Always disclose all supplements and over-the-counter drugs you use.
Yes, tenofovir disoproxil fumarate is available as a generic medication. The brand name version, Viread, lost its patent protection several years ago, allowing multiple manufacturers to produce high-quality generic versions. These generics are required by the FDA to have the same active ingredient, strength, and effectiveness as the brand-name drug. Generic versions are typically much more affordable for patients and insurance providers. Whether you take the brand-name or the generic version, the clinical benefits and the risks remain the same, and you should not switch between them without informing your healthcare provider.
Other drugs with the same active ingredient (Tenofovir Disoproxil)
While rare, some side effects are life-threatening. Stop taking the medication and contact emergency services if you experience:
> Warning: Stop taking Tenofovir Disoproxil and call your doctor immediately if you experience any signs of an allergic reaction, such as hives, difficulty breathing, or swelling of your face, lips, tongue, or throat.
Extended use of tenofovir disoproxil is associated with two primary long-term concerns:
The FDA has issued a Black Box Warning for tenofovir disoproxil regarding two major risks:
Report any unusual symptoms to your healthcare provider immediately. Early detection of side effects is key to maintaining long-term health.
Your healthcare provider will order regular laboratory tests to ensure the medication is safe and effective for you:
Tenofovir disoproxil generally does not affect the ability to drive or operate machinery. However, if you experience dizziness or fatigue as a side effect, you should avoid these activities until you know how the medication affects you.
While there is no direct contraindication between tenofovir and alcohol, excessive alcohol consumption can strain the liver and kidneys, both of which are critical for processing this medication. Chronic alcohol use can also increase the risk of pancreatitis and liver disease, complicating the management of HIV or HBV.
Never stop taking tenofovir disoproxil abruptly. For patients with Hepatitis B, stopping the drug can cause a life-threatening liver flare. If discontinuation is necessary, your doctor will monitor your liver function very closely for several months. For HIV patients, stopping the drug can lead to a rapid increase in viral load and a drop in CD4 cell count.
> Important: Discuss all your medical conditions, especially any history of kidney disease, liver disease, or bone problems, with your healthcare provider before starting Tenofovir Disoproxil.
Tenofovir does not typically interfere with standard laboratory tests, but it can cause 'false' elevations in serum creatinine that reflect actual kidney stress rather than a testing error. It may also cause low phosphorus levels (hypophosphatemia) on a metabolic panel.
> Important: Tell your doctor about ALL medications, supplements, and herbal products you are taking, including over-the-counter pain relievers.
There is no known major cross-sensitivity between tenofovir and other classes of antivirals (like protease inhibitors or integrase inhibitors). However, patients who have had reactions to other nucleotide analogs (like adefovir or cidofovir) should be monitored closely for similar reactions to tenofovir.
> Important: Your healthcare provider will evaluate your complete medical history, including your current kidney and bone health, before prescribing Tenofovir Disoproxil to ensure it is the safest option for you.
Tenofovir disoproxil is approved for children as young as 2 years of age who weigh at least 10 kg.
Patients over the age of 65 may be at higher risk for tenofovir-related complications due to:
This is the most critical special population for tenofovir disoproxil. Patients with a Creatinine Clearance (CrCl) of less than 50 mL/min require a change in how often they take the medication. Failure to adjust the dose can lead to rapid kidney failure or Fanconi syndrome. In patients with severe impairment, switching to Tenofovir Alafenamide (TAF) may be considered, as it has a lower risk of renal toxicity.
Tenofovir pharmacokinetics are not significantly altered by liver impairment. It can be used in patients with various stages of liver disease, but those with 'decompensated' liver disease (where the liver is failing to perform basic functions) must be monitored for signs of lactic acidosis and worsening liver function tests.
> Important: Special populations require individualized medical assessment and more frequent laboratory monitoring.
| Parameter | Value |
|---|---|
| Bioavailability | 25% (Fasted) / ~35-40% (Fed) |
| Protein Binding | < 7% |
| Half-life (Plasma) | 17 hours |
| Half-life (Intracellular) | > 60 hours (Active form) |
| Tmax (Time to peak) | 1.0 ± 0.4 hours |
| Metabolism | Not CYP-mediated; Esterase hydrolysis |
| Excretion | Renal (70-80% unchanged in urine) |
Tenofovir disoproxil is classified as a Nucleotide Reverse Transcriptase Inhibitor (NtRTI). It differs from Nucleoside inhibitors (NRTIs) like zidovudine because it already contains a phosphate group, requiring one fewer phosphorylation step inside the cell to become active. It is therapeutically related to medications like Emtricitabine, Lamivudine, and Abacavir.