Viread

"Viread" (Tenofovir disoproxil fumarate) is a drug used to treat infection with human immunodeficiency virus (HIV). It belongs to the class of antiviral drugs and is a reverse transcriptase inhibitor that works by inhibiting viral RNA-dependent DNA polymerase, inhibiting HIV replication.

Viread is used in combination with other antiretroviral drugs to treat HIV infection in adults and children. It can be used as the main component of an antiretroviral therapy (ART) regimen or in combination with other drugs, such as protease or integrase inhibitors, to achieve optimal control of viral load and preserve immune function.

Viread may also be used for prophylactic purposes, such as preventing HIV infection in people at high risk of infection, such as those who are sexually or injectingually exposed, or in exposed patients, such as health care workers.

It is important to note that the use of Viread should be supervised by a doctor, and the dosage may vary depending on the individual characteristics of the patient and the stage of HIV infection. As with any medication, Viread can cause side effects and it is important to report them to your doctor in a timely manner.

Indications Viread

Viread is used to treat infection with human immunodeficiency virus (HIV). Indications for use of Viread include:

1. Treatment of HIV infection in adults: Viread is used as part of combination antiretroviral therapy (ART) to reduce viral load and maintain immune function in adult patients with HIV infection.
2. Treatment of HIV infection in children: The drug may be used in the treatment of HIV infection in children, in combination with other antiretroviral drugs, depending on the age and characteristics of the patient.
3. Prevention of HIV infection: Viread can be used as a preventive measure to prevent HIV infection in persons at high risk of infection, such as people who inject drugs, sex workers, or partners of HIV-positive persons.
4. Post-exposure prophylaxis: The use of Viread may be considered for individuals at risk for possible post-exposure HIV infection (e.g., health care workers after accidental exposure to contaminated material).
5. Prevention of vertical transmission of HIV: In pregnant women with HIV, Viread may be used during pregnancy and breastfeeding to reduce the risk of vertical transmission to the fetus.
6. Treatment of chronic hepatitis B: Viread may also be used to treat chronic hepatitis B in adults and children.

Viread should be used under the supervision of a doctor and according to the recommendations for the specific situation and stage of HIV infection.

Release form

The drug Viread (Tenofovir disoproxil fumarate) is usually available as oral tablets. Here is more information about the dosage form:

1. Tablets: Viread tablets usually contain the active ingredient tenofovir disoproxil fumarate in various dosages. They are designed to be taken by mouth and can be taken with or without food as recommended by your doctor. It is usually recommended to take one or two tablets per day, but the dosage can be changed depending on the patient's specific situation.

Viread tablets are usually in a convenient coated form, making them easy to swallow and reducing the risk of gastrointestinal irritation.

It is important to note that the specific form and dosage of Viread may vary by country, manufacturer, and doctor's recommendations.

Pharmacodynamics

Its mechanism of action is based on the inhibition of human immunodeficiency virus (HIV) replication in the body. Here's how it works:

1. Inhibition of viral replication: Tenofovir, the active ingredient of Viread, is a nucleotide analog. It is incorporated into the viral DNA strand during the reverse transcriptase process, which is necessary to turn viral RNA into DNA. As a result of tenofovir incorporation, viral DNA cannot be continued, preventing further replication of the virus.
2. Integrase inhibition: Tenofovir also inhibits the activity of integrase, an enzyme that is responsible for integrating viral DNA into the host cell genome. Blocking this process prevents the HIV virus from integrating into the DNA of the host cell and thus makes it more difficult for the virus to replicate.
3. Suppression of viral replication: The effect of tenofovir on reverse transcriptase and integrase is to reduce the viral load in the body. This helps to control HIV infection and maintain or restore the patient's immune system function.

Overall, Viread is an important component in the treatment of HIV infection due to its ability to inhibit viral replication and slow the progression of the disease.

Pharmacokinetics

Here are the main aspects of the pharmacokinetics of Viread:

1. Absorption: After oral administration of Viread, the active substance tenofovir disoproxil is absorbed from the gastrointestinal tract. It undergoes the process of hydrolysis to tenofovir, which is the active form of the drug.
2. Distribution: Tenofovir has a large volume of distribution, which means that it is widely distributed in body tissues. It can penetrate the blood-brain barrier and the placental barrier, reaching concentrations in the central nervous system and fetus in case of pregnancy.
3. Metabolism: Tenofovir disoproxil undergoes hydrolysis in tissues and liver to tenofovir. Tenofovir is mainly metabolized to inactive metabolites, resulting in low systemic metabolism.
4. Excretion: Final excretion of tenofovir is mainly via the kidneys. Approximately 80% to 85% of the dose is excreted unchanged with urine, making it suitable for patients with impaired hepatic function.
5. Half-life: The half-life of tenofovir from blood plasma is approximately 17 hours.
6. DoseKinetics: The dosekinetics of tenofovir are characterized by a linear behavior over the dose range of 75 mg to 600 mg.

7. Dietary exposure: Viread administration with food does not significantly affect the pharmacokinetics of tenofovir.

Taking into account the pharmacokinetic features of Viread allows you to adequately adjust the dosage and schedule of the drug to achieve optimal therapeutic efficacy with minimal risk of side effects.

Dosing and administration

The following are general recommendations for the method of administration and dosage of Viread:

1. Chronic hepatitis B:

   • For adult patients, it is generally recommended to take 1 tablet (tenofovir disoproxil 300 mg) daily.
   • The duration of treatment is determined by the doctor depending on the degree of disease activity and response to treatment.
   • Dose adjustment may be required in patients with impaired renal or hepatic function.

2. HIV infection:

   • In combination with other antivirals, Viread is usually taken 1 tablet (tenofovir disoproxil 300 mg) daily.
   • Treatment regimen and dosage may vary depending on the extent of HIV infection, stage of disease, prior treatment, and other factors.
   • Dose adjustment may be required in patients with impaired renal or hepatic function.

3. Kids:

   • The dosage and use of Viread in children should be determined by a doctor depending on their age, weight and general health.
   • Children are usually prescribed a dosage based on their weight and expressed in milligrams per kilogram of weight.

4. Application:

   • Viread tablets are taken orally, whole, with sufficient water, regardless of meals.
   • It is recommended to take a tablet every day at the same time to maintain a constant level of the drug in the body.

It is important to follow your doctor's instructions and not to change the dosage of Viread without his or her approval. Skipping doses can lead to a decrease in the effectiveness of treatment and the development of virus resistance to the drug.

Use Viread during pregnancy

The use of Viread during pregnancy may be recommended in the following cases:

1. Treatment HIV infection in pregnant women : If a woman is pregnant and infected with human immunodeficiency virus (HIV), the use of antiretroviral therapy (ART), including Viread, may be prescribed to reduce the risk of vertical transmission of HIV from mother to fetus.
2. Treatment of chronic hepatitis B in pregnant women: Viread can also be used to treat chronic hepatitis B in pregnant women if the indication for ART is present.

The use of Viread during pregnancy should be carried out only under the strict supervision of a doctor. He or she should assess the benefits of the drug for the mother and the risks to the fetus. It is also important to consider other factors such as the stage of HIV infection, viral load, fetal condition and other comorbidities.

Contraindications

Despite the effectiveness of the drug, some people may have contraindications to its use. Here are some of them:

1. Known allergic reaction: People with a knownallergy to tenofovir or other components of the drug should avoid using it.
2. Severe kidney damage: The use of Viread may impair kidney function, therefore its use may be undesirable in people with severe kidney disease or impaired kidney function.
3. Pregnancy: The use of Viread during pregnancy may be contraindicated, especially in the first trimester, due to potential effects on the fetus.
4. Breastfeeding: Viread may be excreted into breast milk, therefore its use during breastfeeding may be undesirable.
5. Pediatric Age: The efficacy and safety of Viread in children younger than a certain age (usually under 12 years of age) may be poorly understood, so its use may require special attention and evaluation.
6. Severe hepatic impairment: In the presence of severe hepatic impairment, the use of Viread may be contraindicated due to the possibility of toxic reactions and liver deterioration.

Side effects Viread

Viread can cause various side effects in patients. Here are some of the most common side effects:

1. Increased liver enzyme activity: Some patients may experience an increase in alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels after starting Viread, which may indicate potential liver damage.
2. Diarrhea: Diarrhea may be one of the most common side effects of Viread.
3. Headache: Headache or migraine may occur in some patients.
4. Anxiety or insomnia: Some patients may experience anxiety or insomnia while taking the drug.
5. Blood changes: Changes in blood counts such as decreased white blood cell counts (leukopenia), platelet counts (thrombocytopenia), or hemoglobin levels (anemia) may occur.
6. Osteopenia: Prolonged use of Viread may be associated with an increased risk of osteopenia, which may lead to increased bone fragility.
7. Elevateduric acid levels: Some patients may have elevated levels of uric acid in the blood, which can lead to osteoarthritis or gout.
8. Rash or skin reactions: Some patients may experience a rash or other skin reactions such as itching or redness.
9. Hypersensitivityto sunlight: Some patients may experience hypersensitivity to sunlight or photosensitivity.
10. Kidney problems: In some patients, Viread may cause problems with kidney function, such as increased blood creatinine levels or kidney failure.

Overdose

An overdose of Viread can lead to a variety of serious complications and side effects. Since there is limited information about specific symptoms and consequences of Viread overdose, it is important to seek medical attention immediately if an overdose is suspected or if unpleasant symptoms occur after using the drug.

Symptoms of overdose may include:

1. Increased side effects: Worsening of already existing side effects such as nausea, vomiting, diarrhea, headache, arthralgia, etc.
2. Increased risk of toxic effects on kidneys and bones: Tendency to develop acute renal failure, osteoporosis and other kidney and bone related complications.
3. Liver disorders: Hepatotoxicity and liver damage may occur.
4. Neurological symptoms: Dizziness, seizures, disorders of consciousness and other neurological symptoms may occur.
5. Other systemic manifestations: Various systemic manifestations of overdose are possible, including hypercalcemia, hypophosphatemia and others.

Treatment of Viread overdose should be symptomatic and aimed at relieving symptoms, maintaining the functions of organs and body systems, and removing excess drug from the body. It is important to seek medical attention as soon as possible if an overdose of Viread is suspected or if any unpleasant symptoms occur after taking the drug.

Interactions with other drugs

The drug Viread may interact with other medicinal products, which may alter their efficacy, safety or cause undesirable side effects. Some of the known interactions are listed below:

1. Drugs metabolized via cytochrome P450 enzymes: Viread may affect the metabolism of other drugs metabolized via cytochrome P450 enzymes, such as cyclosporine, tacrolimus, antiarrhythmic drugs (e.g. Amidarone) and some antibiotics (e.g. Clarithromycin). This may lead to changes in their concentration in the blood and require dosage adjustment.
2. Drugs thatinduce tubular secretion: Drugs such as neifedipine or radiocontrast agents may affect tubular secretion in the kidneys, which may increase the blood concentration of tenofovir.
3. Drugs thataffect renal excretion: Drugs that affect kidney function or excretion may increase the risk of undesirable side effects of Viread. This includes some nonsteroidal anti-inflammatory drugs (NSAIDs), antibiotics, and diuretics.
4. Drugs that cause hyperkalemia: Some medications, such as angiotensin-converting enzyme inhibitors (ACEIs) or androgens, may increase blood potassium levels, which may increase the hyperkalemia caused by Viread.
5. Drugsaffecting bone metabolism: Drugs that affect bone metabolism, such as calcium or vitamin D, may interact with Viread, causing changes in bone density or bone composition.