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Tvir
Last reviewed: 23.04.2024
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Tenvir is a drug that has an effect on hepatitis type B, as well as HIV infection.
Indications Tannira
It is used for therapy in HIV and AIDS. In addition, it is used in separate schemes of combined treatment for type B hepatitis. It must also be taken during antiretroviral treatment.
[1]
Release form
The preparation is sold in tablet form, 30 pieces per container, equipped with bags containing silica gel. There is 1 such container inside the pack.
[2]
Pharmacodynamics
The substance of tenofovir disoproxil after absorption is transformed into the active element tenofovir, which is an analogue of a monophosphate nucleotide. After this, the substance is transformed into the active degradation product, tenofovir 2-phosphate (with the participation of constructively expressed cell enzymes).
The intracellular half-life of tenofovir 2-phosphate is equal to 10 hours in the active state, and also 50 hours while staying in a calm state inside peripheral blood mononuclear cells.
This element slows the reverse transcriptase of HIV-1, as well as polymerase HBV, by competitive direct synthesis with the natural substrate of the deoxyribonucleotide element, thereby rupturing the DNA chain after its connection with it.
Tenofovir 2-phosphate has a weak retarding effect on the polymerase cells α, β, as well as γ. In vitro tests show that tenofovir at a level up to 300 μmol / l affects both the binding of mitochondrial DNA or the process of formation of lactic acid.
[3]
Pharmacokinetics
Absorption.
There is evidence that when ingested by a patient with HIV infection, tenofovir fumarate disoproxil is absorbed at high speed, transforming into an element of tenofovir. When a large number of portions of tenofovir fumarate disoproxil were used along with food in individuals with HIV infection, the average for tenofovir was Cmax (326 (36.6%) ng / ml), AUC 0-∞ (3.324 (41.2%) ng h / ml), as well as the Cmin values (64.4 (39.4%) ng / ml).
Peak serum values of tenofovir are recorded after about 60 minutes with fasting and about 120 minutes with food. After taking drugs on an empty stomach, the level of bioavailability is about 25%. When consumed together with fatty foods, the bioavailability of the medication increased (in addition, the AUC (by approximately 40%) and Cmax (approximately by 14%) also increased).
When receiving the first portion of the drug, which was introduced after eating fatty foods, median serum Cmax values were approximately 213-375 ng / ml. In this case, the use of the drug with lighter dishes did not have a significant effect on its pharmacokinetic profile.
Distribution processes.
It was noted that the inside of the TENVIR is distributed within a variety of tissues, with the highest values being seen inside the liver with the kidneys, as well as intestinal contents (preclinical tests). Synthesis with plasma or serum protein in in vitro tests was equal to less than 0.7%, respectively, and 7.2% (with a range of LS in the range 0.01-25 μg / ml).
Exchange processes.
In vitro testing revealed that neither the active element of the drug, nor its metabolic products, are substrates of the CYP450 enzymes.
Excretion.
Tenofovir is mainly excreted through the kidneys - through filtration, as well as through the active tubular type transport system. The unchanged component is excreted in the urine (about 70-80% of the accepted dosage).
The total clearance level is about 230 ml / h / kg (approximately 300 ml / minute). The values of renal clearance are approximately 160 ml / h / kg (approximately 210 ml / minute), which is higher than the glomerular filtration rate. This fact confirms the high importance of tubular secretion during excretion of tenofovir.
With oral administration, the final half-life of tenofovir is 12-18 hours.
Dosing and administration
Take Tenwire is only allowed as part of antiretroviral treatment. If taken as a monotherapy, without the addition of other therapeutic agents, the desired effect will not develop, because tenofovir has a weak inhibitory effect.
You need to consume the drug before meals or with it, in the amount of the 1st pill, once a day. The interval between uses should be no more than 24 hours. If you miss the time you need to take the medicine as soon as possible.
Do not increase the dosage. Per day (once) is allowed to take a maximum of 0.3 g of medicament. In general, independent increase or decrease in the size of a portion is forbidden, because it can accordingly increase the likelihood of overdose or weaken the drug effectiveness.
Tablets are used whole, without preliminary grinding. Drink them with plenty of water.
Use Tannira during pregnancy
The medicine should be carefully prescribed to pregnant women. Since there is no information on how tenofovir affects fetal development, it is necessary to first assess the benefits to the woman from its use and the likelihood of risk to the fetus.
People who are being treated with Tenvir should use reliable contraceptives during this period.
Contraindications
Among the contraindications:
- people who, in addition to the underlying pathology, also suffer from polyneuropathy;
- functional disorders of the kidneys in a severe degree;
- The presence of hypersensitivity to the elements that are part of the drug.
Caution when using is needed in such cases:
- kidney failure, in which the level of CK is in the range of 30-50 ml / minute;
- the patient needs hemodialysis sessions.
If you have the above factors, take the drug under the supervision of a doctor. Medical control is also required when used in people over 65 years of age.
If you need to take Tenvira from a lactating woman, for the duration of therapy, you must stop breastfeeding.
[4]
Side effects Tannira
The use of the drug may cause some side effects:
- violations of the function of systemic blood flow and lymph: the development of anemia or neutropenia;
- immune disorders: the appearance of signs of allergy;
- problems with metabolic processes: the development of lactic acidosis, hyperglycemia, as well as hypophosphatemia or hypertriglyceridemia;
- mental disorders: the emergence of insomnia or abnormal dreams;
- disorders in the work of the National Assembly: the occurrence of headaches, thoracic or respiratory disorders, as well as dizziness and difficulty in the respiratory process;
- disorders affecting digestive activity: the development of vomiting, diarrhea, dyspeptic symptoms, nausea, pain in the epigastric region and pancreatitis. There is also an increase in the level of amylase (for example, in the pancreas region), bloating and an increase in the values of serum lipase;
- lesions of the epidermis and subcutaneous layers: a rash that has a pustular, vesicular or maculopapular shape, a change in the shade of the epidermis (increased pigmentation), itching and urticaria;
- problems with musculoskeletal activity and the function of connective tissues: an increase in the values of creatine kinase. Osteomalacia, rhabdomyolysis, as well as weakness in muscles and myopathy can develop;
- disorders of the function of urination: proteinuria, increased creatinine, kidney failure (in acute or chronic stage), tubulopathy in the kidney area, which has a proximal character (this includes Fanconi syndrome), and in addition necrosis tubules in acute form and more.
Interactions with other drugs
It should be noted that it is forbidden to combine the drug with most medicines. This is due to the fact that Tenvir is incompatible with many drugs. Therefore, with the simultaneous use of drugs can develop quite severe negative symptoms, as well as weaken or completely neutralize the therapeutic effectiveness of Tenvir. Below are the interactions of the drug with individual medicines.
When combined with didanosine, its medicinal values increase. Therefore, such a combination is forbidden (only in a few cases, a variant with a decrease in the dose of didanosine may be considered).
Combination with atazanavir causes a decrease in its indices, as well as a parallel increase in the values of tenofovir. Such a drug combination is allowed only with the additional potentiation of the effect of atazanavir with ritonavir.
Simultaneous reception with ritonavir and lopinavir increases the level of tenofovir, so this combination is prohibited.
Application together with darunavir approximately by 20-25% increases the values of tenofovir. Use these medications in standard servings, while carefully following the nephrotoxic effects of tenofovir.
When combining Tenvir with cidofovir, ganciclovir or valganciclovir, the indices of tenofovir or the drug that is taken simultaneously with it increase. Therefore, these medicines should be used with caution, avoiding the development of side effects. Nephrotoxic drugs are also capable of increasing the serum level of tenofovir.
If the patient has chronic pathologies in which regular use of medicines is required, it is necessary to consult with your doctor about their compatibility with Tenvir.
Storage conditions
Tenvir is required to be kept in a place that is closed from moisture and sunlight, where there is no access for young children. The temperature level should be a maximum of 30 ° C.
[10],
Shelf life
The tenier can be applied within 24 months after the release of the therapeutic drug.
Attention!
To simplify the perception of information, this instruction for use of the drug "Tvir" translated and presented in a special form on the basis of the official instructions for medical use of the drug. Before use read the annotation that came directly to medicines.
Description provided for informational purposes and is not a guide to self-healing. The need for this drug, the purpose of the treatment regimen, methods and dose of the drug is determined solely by the attending physician. Self-medication is dangerous for your health.