What is an HIV infection?
Lamivudine is a nucleoside reverse transcriptase inhibitor (NRTI) that forms a chemical analog of cytidine that belongs to the nucleosides. The drug is used to treat HIV-1 infections such as AIDS. Although the remedy is unable to cure the disease, it does prolong the life expectancy of patients.
Lamivudine is produced by the British pharmaceutical company GlaxoSmithKline. In Germany the antiviral agent has been used since 1995. It is now one of the most widely used nucleoside reverse transcriptase inhibitors in the treatment of HIV infection. Often, a combination with abacavir (ABC), which also belongs to the NRTI.
Lamivudine is a so-called prodrug. This refers to a drug precursor that does not have any effect on the viruses. Only within the organism it comes to the conversion into the actually effective drug. This has the ability to inhibit the enzyme reverse transcriptase. This effect stops the replication of the HI virus. By lowering the number of viruses in the blood, the amount of special white blood cells, such as the CD4-positive T-lymphocytes, increases at the same time. This process leads to a stronger immune defense of the body.
A disadvantage of lamivudine is that the HI virus rapidly develops an insensitivity to the individual drug due to its high mutability. In order to avoid this resistance, the antiviral agent is combined with other active ingredients. Thus, in the context of AIDS therapy usually three active ingredients are used simultaneously.
The enzyme reverse transcriptase is also important for the hepatitis B virus (HBV) in order to multiply. If lamivudine is used to treat hepatitis B, it will reduce the number of viruses and relieve the burden on the liver. If chronic hepatitis B is present, the patient receives lamivudine as a single preparation. The dosage is lower than in the treatment of HIV infection.
The oral bioavailability of lamivudine is considered high at around 80 percent. There are hardly any influences from the intake of food. The plasma half-life of the drug is about six hours. Its degradation takes place exclusively via the kidneys.
Medical application & use
Lamivudine is used to fight the human immunodeficiency virus HIV, which causes AIDS. The antiviral in some cases also ensures that the disease breaks out only at a later date. Basically, the drug increases the life expectancy of AIDS patients and improves their quality of life.
Furthermore, lamivudine is suitable for the treatment of hepatitis B. Thus, the drug counteracts the risk of cirrhosis of the liver. Sometimes even a healing of the disease is possible. In the event that a transplantation of the liver has been performed, lamivudine reduces re-infection of the organ with hepatitis B viruses that are still in the body.
The presentation of the virostatic agent takes place in the form of tablets. Their dose is between 100 and 300 milligrams. Likewise, a solution can be taken. As a rule, the patient receives lamivudine one or two times a day, regardless of the meals.
Risks & Side Effects
Although lamivudine is generally well tolerated, several undesirable side effects are still possible. These include, but are not limited to, limitations in performance, fatigue, headache, chills, fever, swelling of the lymph nodes, ]] diarrhea]], nausea, vomiting, digestive problems, general malaise and flu-like symptoms.
Some patients are more likely to get infections. Other side effects may include liver dysfunction, an inflamed liver, an increase in the enzyme amylase, joint pain, muscle aches and hair loss.
In the case of AIDS, deficiency of white and red blood cells and platelets is more common. Patients suffering from hepatitis B are less likely to be affected.
In the case of AIDS patients, lamivudine therapy can sometimes even aggravate the symptoms. The reason for this is a reaction of the stronger immune system to pathogens such as viruses, bacteria, fungi or parasites that are still in the body. Doctors then talk about an immune reactivation syndrome. In most cases, however, the symptoms improve after about four weeks.
If hypersensitivity to lamivudine is present, no drug therapy should be performed. Renal impairment may require adjusting the dose. If symptoms such as pain in the hands and feet, tingling, numbness, enlargement of the liver or inflammation of the organ occur, the treating physician must weigh the risk and benefit of the therapy well.
The same applies to the use of lamivudine during pregnancy and lactation. Thus, animal experiments have harmful effects on the unborn child. However, it is still unclear whether these risks exist in humans. Basically it is recommended not to administer lamivudine in early pregnancy. In the case of HIV infection, the patient must abstain from breastfeeding her child. Otherwise there is a risk that the HI virus with the mother's milk on the child passes.
In principle, the use of lamivudine in children under three months is ruled out, since the findings on the effect of the drug are not sufficient for them. In older children, the dosage of the drug depends on their body weight and the course of the disease.
Because of the neurotoxic effects of lamivudine, no other drugs that have a similar effect should be used. These include cisplatin, vincristine, isoniazid and ethambutol.