Combivir is a combined antiviral agent used in the therapy of HIV infection. The drug contains two active components that jointly inhibit the reproduction of human immunodeficiency virus, slowing down the progression of the disease and improving the immune status of patients. It belongs to the group of nucleoside reverse transcriptase inhibitors and is used as part of antiretroviral therapy (ART). Combivir is effective in controlling HIV-1 infection, reducing viral load and preventing the development of AIDS, allowing patients to maintain a high quality of life.
no RX
Dosage | Package | Per Item | Per Pack | Order |
150 mg + 300 mg |
|
The trade name of the drug is Combivir. This is the registered name under which the drug is known in medical practice and is available in the pharmacy network.
The international nonproprietary name is lamivudine + zidovudine. These names denote the two active active ingredients in the drug and are used in pharmacology internationally.
Combivir is available as film-coated tablets containing a fixed combination of 150 mg lamivudine and 300 mg zidovudine. Tablets have white color, oval shape and are packed in blisters of 10 pieces or vials of 60 pieces. This form provides convenience of use and accurate dosing of active components in combination therapy.
The main active components are lamivudine (150 mg) and zidovudine (300 mg) in each tablet. These substances act synergistically, enhancing the antiviral effect of the drug.
The tablets contain such excipients as microcrystalline cellulose, sodium starch glycolate, magnesium stearate, colloidal anhydrous silicon dioxide, as well as film coating of hypromellose, titanium dioxide, polyethylene glycol and polysorbate 80. These components ensure stability and bioavailability of active substances.
Combivir is a combination of two nucleoside analogs, lamivudine and zidovudine, which inhibit HIV reverse transcriptase. Lamivudine and zidovudine, after phosphorylation inside cells, are converted into active triphosphate forms that competitively block the reverse transcriptase enzyme needed to convert viral RNA into DNA. This interrupts the viral replication process, preventing the virus from replicating in infected cells. In addition, the incorporation of these analogs into the growing viral DNA strand causes it to break, which further suppresses viral activity.
Lamivudine is highly active against HIV-1 and to a lesser extent against hepatitis B virus, while zidovudine enhances the antiviral effect by providing a broader spectrum of action. Synergism of these components allows to reduce the viral load in the blood to an undetectable level with proper adherence to the therapy regimen. The drug does not completely destroy the virus, but significantly slows the progression of infection, improving the function of CD4-lymphocytes and preventing the development of opportunistic diseases. The effect is noticeable after 4-12 weeks of regular administration as part of ART.
Lamivudine and zidovudine are well absorbed from the gastrointestinal tract after oral administration. The maximum plasma concentration of lamivudine is reached after 0.5-2 hours, and that of zidovudine after 0.5-1.5 hours. Bioavailability of lamivudine is about 86%, zidovudine - about 64%, and food intake may slightly slow absorption, but does not affect the overall efficacy.
Lamivudine binds to plasma proteins by less than 36% and zidovudine by 34-38%. The volume of distribution of lamivudine is about 1.3 L/kg and that of zidovudine is about 1.6 L/kg, indicating their penetration into tissues, including the central nervous system and cerebrospinal fluid. Both substances cross the placental barrier.
Lamivudine is minimally metabolized (5-10%) and is excreted predominantly unchanged. Zidovudine undergoes more intensive metabolism in the liver with the participation of glucuronidation enzymes, forming an inactive metabolite - 5'-glucuronide zidovudine, which is about 75% of the administered dose.
The elimination half-life of lamivudine is 5-7 hours, that of zidovudine is 0.8-1.2 hours. Lamivudine is excreted through the kidneys (about 70% unchanged), zidovudine - through the kidneys (about 14% unchanged, the rest in the form of metabolites) and partially through the intestine. Complete excretion takes about 24 hours.
Combivir is indicated for the treatment of the following conditions:
The drug is used exclusively in combination with other antiretroviral agents to prevent resistance.
The use of Combivir is prohibited in:
With caution administered in hepatitis B or C, obesity, bone marrow dysfunction.
Combivir tablets are taken orally, drinking water (100-150 ml), regardless of meals. Tablets are not chewed and crushed to keep the fixed combination of active substances. It is recommended to adhere to the same time of intake to maintain stable concentration.
The standard dose is 1 tablet (150 mg lamivudine + 300 mg zidovudine) twice daily, 12 hours apart.
Dosage - half a tablet (75 mg lamivudine + 150 mg zidovudine) twice daily.
In renal insufficiency (creatinine clearance less than 50 ml/min) the drug is not used in a fixed combination; separate drugs with dose adjustment are used. In hepatic insufficiency correction is not required, but monitoring of the condition is necessary.
Possible adverse reactions include:
Side effects are more likely to occur in the first few weeks and require monitoring.
Nausea, dizziness, anemia, neutropenia, neutropenia, lactoacidosis may occur when taking doses higher than recommended (e.g., more than 4 tablets per day).
Stop taking, call a doctor. Gastric lavage (if less than one hour has elapsed) and give activated charcoal. Symptomatic treatment in hospital is required.
Combivir increases the toxicity of drugs that inhibit bone marrow (hansivir). Ribavirin reduces the activity of zidovudine. CYP3A4 inhibitors (ketoconazole) may increase the concentration of the components.
Alcohol increases the risk of lactoacidosis. Food does not affect efficacy but improves tolerability.
Use in the first trimester of pregnancy is limited; in the second and third trimesters, by strict indication. Breast-feeding is prohibited due to penetration into milk.
The drug may cause fatigue and dizziness, which requires caution when driving.
The elderly need monitoring of renal and blood function. In children, the dosage is adjusted for body weight.