Zeffix is a solution for oral use. It is a systemic drug with antiviral properties.
The active component of the drug, lamivudine, is an antiviral agent with a high activity against hepatitis type B.
Triphosphate lamivudine is an active form of the substance - it is a substrate for polymerase of the virus. The subsequent formation of the DNA of the virus is blocked by the entry of the drug component into the interior of this chain. TF lamivudine does not interfere with the natural cellular metabolism of DNA.
The active ingredient has a high absorption index from the digestive tract, and the bioavailability level after internal reception is 80-85%. Peak serum concentration is observed after 1 hour after use. When the drug is used together with food, the peak of serum concentration is reduced to 47%, and the time of its reaching is extended. But in general, the indicators of the absorbed substance is not affected, which allows you to use Zephics, regardless of food.
When distributed in medicinal dosages, the parameters of the substance will be linear. The drug is poorly synthesized with a plasma protein. There is a limited amount of information that lamivudine is able to pass into the central nervous system and the cerebrospinal fluid. The average ratio of the substance in the blood serum and cerebrospinal fluid after 2-4 hours after oral administration is about 0.12.
Metabolic interaction of the substance is hardly possible, since the substance has a rather low level of metabolism in the liver (only 5-10%), as well as weak synthesis with a plasma protein.
The average index of the systemic clearance coefficient for lamivudine is approximately 0.3 l / h / kg. The half-life lasts about 5-7 hours. The main part of the active ingredient is excreted unchanged together with the urine with the help of an active process of secretion, as well as glomerular filtration. Kidney clearance is approximately 70% of the excreted lamivudine.
Use of the zephix during pregnancy
There is a lot of information that the medicine does not have a toxic effect on the body and does not cause developmental defects. The drug is allowed to use during pregnancy if there are clinical indications.
When pregnancy occurs during the treatment with Zephix it is necessary to take into account that after stopping the use of drugs, the pathology can become aggravated.
Among the contraindications of drugs - patient's intolerance of lamivudine or other components of the drug. In addition, it is not recommended to prescribe the drug to children under 18 years of age, since there is insufficient information on the use of this drug in the above age category.
Side effects of the zephix
The use of drugs can cause some side reactions, the most common of which are: infectious processes in the respiratory system, fatigue and a sense of discomfort, and in addition also headaches, abdominal pain, diarrhea, vomiting, discomfort in the tonsils and throat, and together with this nausea.
In addition, it is also possible to develop such negative effects:
- organs of the digestive system: most often increases the ALT, and then there is an exacerbation of hepatitis (it can develop both during the course of treatment, and after the abolition of drugs). Often, the level of ALT is soon lowered, until death occurs in isolated cases;
- connective tissue, musculature and bone structure: often develop muscle problems (the appearance of seizures, pain), as well as increase in the parameters of CK. Single rhabdomyolysis appears;
- organs of the lymphatic and hematopoietic system: thrombocytopenia develops singly;
- the immune system: sometimes there are manifestations of hypersensitivity - edema Quincke;
- subcutaneous tissue and skin: often there is an itch, and also a rash.
There have been cases of development of pancreatitis, as well as neuropathy of the nerve (or paresthesia) in patients with HIV, but it has not been possible to track the clear relationship between treatment with Zephix and the development of the above pathologies.
In HIV-infected people who took the drug in combination with nucleoside analogs, lactatacidosis sometimes developed, usually accompanied by fatty hepatosis and severe form of hepatomegaly.
Interactions with other drugs
Excretion of the drug mainly occurs through the kidneys (active secretion). Therefore, it is necessary to take into account that it can interact with drugs that have the same basic excretion pathway (in this case the procedure takes place with the participation of the organic cation transfer system, for example, with trimethoprim).
Combined use with trimethoprim or sulfamethoxazole in the amount of 160/800 mg increases the plasma lamivudine values by 40%. However, Zephix does not affect the pharmacokinetic properties of the above substances. But adjust the dosage of the drug in the case of normal kidney work is not needed.
The use of drugs together with zidovudinom moderately increases the maximum values of the latter in plasma (28%), but the AUC remains without significant changes. The pharmacokinetics of Zephix under the action of zidovudine does not change.
When combined with zalcitabine, Zephiks is able to inhibit the process of phosphorylation of this substance inside cells. In this regard, it is recommended not to use these medications at the same time. The same applies to the substance emtricitabine - due to the same effect of Zephix on it, it is forbidden to combine these drugs.
The active substance of ZeffiX in vitro helps the intracellular reproduction of cladribine, resulting in a risk of loss of the latter's effectiveness when combined. Individual clinical data also confirm the possibility of interaction between these drugs. Because of this, their use in combination is not recommended.
To simplify the perception of information, this instruction for use of the drug "Zeffix" 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.