Duovir-N (Lamivudine, Zidovudine and Nevirapine)

Duovir-N general information

What is Duovir-N used for?

Duovir-N is a fixed dose combination treatment for Human Immunodeficiency Virus (HIV) infection in adults. Duovir-N tablets are used to treat HIV patients who have already been treated with other HIV medications and have responded well to each of the drugs in the combination; and are also able to tolerate each of these medications, at the recommended doses without requiring a dose adjustment due to low weight. HIV impairs the immune system by attacking specific immune cells called CD4+ cells that are involved in fighting infection, and this can lead to opportunistic life-threatening infection (infections that would not normally be harmful); also if too many CD4+ cells are destroyed this can result in acquired immune deficiency syndrome (AIDS). Duovir-N tablets prevent or slow down the ability of HIV to replicate and spread, which keeps the amount of virus (viral load) down to a low level; allowing the numbers of CD4+ cells to increase, so that the immune system can recover, reducing the risk of disease progression. Triple drug therapy with Duovir-N makes it easier to take the medications regularly, which helps improve compliance and helps prevent resistance of HIV to individual drugs.

How does Duovir-N work?

Duovir-N tablets contain a combination of three antiretroviral drugs; nevirapine, zidovudine and lamivudine, which are effective only against RNA viruses (retroviruses) like Human Immunodeficiency Virus (HIV). These three drugs each work by inhibiting the action of the viral-specific enzyme reverse transcriptase (RT) which is needed for the virus to be able to replicate. Retroviruses convert RNA to DNA, which is then integrated into the DNA of infected immune cells so that the virus can replicate. Nevirapine in Duovir-N tablets is a non-nucleoside reverse transcriptase inhibitor (NNRTI); nucleosides are the precursors to the building blocks of DNA and RNA. Nevirapine in Duovir-N tablets acts by binding to a specific site on the RT enzyme, the enzyme's active site known as the NNRTI pocket, disrupting the catalytic site of the enzyme, and blocking its action in a manner that is noncompetitive with nucleosides. Zidovudine and lamivudine are both nucleoside analogue reverse transcriptase inhibitors (NRTI), which means that they block the action of RT by competing with one of the nucleosides needed to transcribe the viral RNA into DNA, becoming incorporated into the chain of newly synthesized viral DNA and preventing it from growing (chain termination). Zidovudine is an analogue of thymidine and lamivudine is an analogue of cytidine. The combined action of the three antiiretroviral drugs in Duovir-N tablets prevents the integration of the virus into the DNA of the infected CD4+ immune cell by 2 different mechanisms, which inhibits the replication of HIV so that no more virus can be produced, and this reduces the viral load (amount of virus). Duovir-N slows down the replication of HIV within your body but does not kill the virus already incorporated in the CD4+ cells or prevent the spread of the infection to others.

What does Duovir-N contain?

Duovir-N tablets contain a combination of the active ingredients nevirapine (200mg) lamivudine (150mg) and zidovudine (300mg), which are antiretroviral drugs that are used to treat HIV infection.

Treating HIV infection with Duovir-N

Duovir-N tablets contain a combination of three antiretroviral drugs zidovudine, lamivudine and nevirapine, which are effective only against RNA viruses (retroviruses) like Human Immunodeficiency Virus (HIV). HIV impairs the immune system by attacking specific immune cells called CD4+ cells that are involved in fighting infection, and this can lead to opportunistic life-threatening infection (infections that would not normally be harmful), including pneumonia, herpes virus infections, and Mycobacterium avium complex (MAC) infection. If too many CD4+ cells are destroyed this can result in acquired immune deficiency syndrome (AIDS). The three antiretroviral drugs in Duovir-N tablets each work by inhibiting the action of the viral-specific enzyme reverse transcriptase (RT), which is needed for the virus to be able to replicate, as it converts viral RNA to DNA, so that viral DNA can become integrated into the DNA of infected immune cells allowing the virus can replicate. Duovir-N prevents the integration of HIV into the DNA of the infected CD4+ cell, which inhibits the replication of HIV so that no more virus can be produced, and this reduces the viral load (amount of virus). Duovir-N tablets slow down the replication of HIV within your body but does not kill the virus already incorporated in the CD4+ cells or prevent the spread of the infection to others.

What are the side effects of Duovir-N?

The most commonly reported side effects when taking Duovir-N include: headache, gastrointestinal upset, particularly nausea, also diarrhoea, constipation, stomach pain; dizziness, fatigue, difficulty sleeping, rash, hair loss, muscle and joints aches and pains. A more serious but less common side effect is damage to the liver, severe rash and a condition called lactic acidosis, which may cause pancreatitis, liver failure, or renal failure. Also redistribution/accumulation of body fat can happen.

What are the health risks when taking Duovir-N?

Lactic acidosis is a rare but potentially fatal condition that has been reported when taking an antiretroviral nucleoside analogue, such as in Duovir-N tablets. It is caused by a build up of excess of lactic acid in the blood due to liver damage, which is usually associated with hepatomegaly (liver enlargement) with steatosis (build up of fat in the liver) and may cause pancreatitis, liver failure, or renal failure. Symptoms begin within a few months of treatment and include: nausea, vomiting and abdominal pain, difficulty breathing, loss of appetite, weight loss, motor weakness. Nevirapine in Duovir-N tablets can cause severe and life-threatening skin reactions and serious liver failure, this is why it important that you have already tried nevirapine before using combination therapy.

When should Duovir-N not be used?

You should not use Duovir-N if you:

• are allergic to nevirapine, lamivudine or zidovudine or any ingredients in Duovir-N tablets
• are pregnant or are breastfeeding, without discussion with your doctor
• have abnormally low neutrophil counts (<0.75 x 109/l), or abnormally low haemoglobin levels (<7.5 g/dl or 4.65 mmol/l)
• have had any blood disorders such as anaemia or bone marrow problems
• have kidney or liver disease
• are just starting HIV therapy and have not used nevirapine previously
• are taking medicines that interact with Duovir-N, including: the antibiotic trimethoprim, the antriretrovirals zalicitabine and stavudine, the antiinfective atovaquone, the anticonvulsant phenytoin, probenecid for gout, the antivirals ribavirin and ganciclovir, the antibiotic rifampicin, the narcotic analgesics codeine and morphine, methadone for treatment of narcotic withdrawal, the non-steroidal anti-inflammatories (NSAID) aspirin, indomethacin, ketoprofen and naproxen, oxazepam and lorazepam for anxiety and sleeping problems, cimetidine for peptic ulcers, clofibrate for high cholesterol, the antiinfective dapsone, the immune modulator and antiviral Isoprinosine, the antiinfectives, pentamidine, dapsone, pyrimethamine, co-trimoxazole, amphotericin and flucytosine, vincristine, vinblastine and doxorubicin for cancer treatment, the immune modulator interferon, the antibiotic clarithromycin, St John's wort, oral contraceptives, the antifungal ketoconazole

What medications interact with Duovir-N?

Several medications interact with Duovir-N and should either not be taken while you are taking Duovir-N or only after discussion and instruction from your doctor:

• Drugs that cause a serious reaction with Duovir-N: the antiinfectives, pentamidine, dapsone, pyrimethamine, co-trimoxazole, amphotericin and flucytosine, the antiviral ganciclovir, vincristine, vinblastine and doxorubicin for cancer treatment, the immune modulator interferon
• Drugs that affect Duovir-N: the antibiotic trimethoprim, the antiinfective atovaquone, probenecid for gout, the antiviral ribavirin, the antibiotic rifampicin, the narcotic analgesics codeine and morphine, methadone for treatment of narcotic withdrawal, the non-steroidal antiinflammatories (NSAID) aspirin, indomethacin, ketoprofen and naproxen, oxazepam and lorazepam for anxiety and sleeping problems, cimetidine for peptic ulcers, clofibrate for high cholesterol, the antiinfective dapsone, the immune modulator and antiviral Isoprinosine, St John's wort
• Drugs that are affected by Duovir-N: the antriretrovirals zalicitabine and stavudine, the anticonvulsant phenytoin, the antibiotic clarithromycin, oral contraceptives, the antifungal ketoconazole

How should Duovir-N be taken?

You should take your Duovir-N tablets, 1 tablet twice daily, with a glass of water, with or without food. Since each tablet of Duovir-N contains half of the commonly prescribed daily doses of each of the 3 constituent drug, zidovudine, lamivudine and nevirapine, you should not need to change the dose of Duovir-N. You should continue to take your Duovir-N for as long as recommended by your doctor, and you will be monitored carefully to ensure that you do not develop any serious side effects, in which case your doctor will probably recommend that you stop taking your Duovir-N tablets.

How long should you take Duovir-N?

You should take your Duovir-N tablets continually for as long as recommended by your doctor, and you will be monitored carefully to ensure that you do not develop any serious side effects, in which case your doctor will probably recommend that you stop taking your Duovir-N tablets.

Missed dose of Duovir-N

If you miss a dose of Duovir-N take it as soon as you remember, unless it is time to take the next dose, then skip the missed dose. Do not take a double dose.

How should Duovir-N be stored?

You keep your Duovir-N tablets below 30°C in a cool dry place.