Zalcitabine is an orally administered medicine, used to treat HIV infection. HIV, or human immunodeficiency virus, is responsible for causing AIDS, or acquired immunodeficiency syndrome, in which the body's immune system becomes so weak it can't resist ordinary infection and leads to death of the person affected.
Zalcitabine belongs to a group of drugs known as reverse transcriptase inhibitors. Lamivudine (Epivir), zidovudine (Retrovir), stavudine (Zerit) and didanosine (Videx) are other drugs of this class.
When HIV infects the body, it multiplies within the body cells. The new viruses are then released from the cell and infect other cells, spreading throughout the body. Even the new cells that are continually being produced in the body are not able to escape and the infection is perpetuated.
In order to multiply, the HIV virus needs new DNA. It forms new DNA by using the enzyme reverse transcriptase. Zalcitabine, when taken by the patient, gets converted to an active compound called dideoxycytidine triphosphate, inside the body. Dideoxycytidine triphosphate is structurally similar to deoxycytidine triphosphate, a compound that interacts with reverse transcriptase to form new DNA. So, now it is deoxycytidine triphosphate that interacts with reverse transcriptase and inhibits its action thus stopping the formation of new DNA.
Thus, zalcitabine only prevents the multiplication and spread of HIV virus; it does not kill the existing viruses and is not a cure for HIV infection or AIDS. It received the FDA's approval in June, 1992.
Zalcitabine can cause lactic acidosis, a condition in which lactic acids get built up in the body. The symptoms of lactic acidosis begin slowly but worsen over time. They may include unusual weakness with muscle pain, trouble in breathing, uneven or fast heart rate, stomach pain, nausea, vomiting, and cold feeling or numbness in arms and legs. If you are taking zalcitabine and notice these symptoms, even though mild, tell your doctor immediately about them. Left untreated, lactic acidosis can be fatal.
In addition, zalcitabine can affect liver or pancreas with serious, life threatening effects. The symptoms include severe pain in the upper stomach that spreads to the back, fast or uneven heart rate, diarrhea, nausea, vomiting, low fever, loss of appetite, clay colored stools, dark urine and jaundice showing in yellowish skin or eyes. If you are on zalcitabine and experience any of these symptoms, again tell you doctor immediately about them.
Zalcitabine can also be harmful to the foetus. On the other hand, HIV can infect the newborn child if the mother is left untreated during pregnancy. So, treatment is must, but care is required in the selection of medication. If you have HIV infection or are pregnant, or plan to become pregnant soon, talk to your doctor about it. If zalcitabine is prescribed to you during pregnancy, your name might be listed on the antiviral pregnancy registry. This is to track the effects of zalcitabine on the baby.
Breast feeding is strictly forbidden for women having HIV or AIDS, whether they are using zalcitabine or not. The virus may pass to the baby with breast milk, even if it was born without HIV.
Zalcitabine inhibits the multiplication of HIV in AIDS patients having advanced HIV infection. It does not cure AIDS and is not known to have reduced the frequency of HIV infection. Another class of reverse transcriptase inhibitors, that is, nucleoside or nucleotide reverse transcriptase inhibitors (NRTIs), like zidovudine or lamivudine, has proved to be more useful in treating AIDS and HIV related illnesses. However, their effectiveness is increased when they are used in conjunction with zalcitabine. Talk to your doctor for more information.
Zalcitabine should be taken with a glass of water, usually every eight hours. However, in case the patient has kidney diseases, the frequency may be decreased to every 12 or 24 hours by the doctor.
The medicine is absorbed better if taken on an empty stomach, that is, at least one hour before a meal or two hours after it.
Zalcitabine should be used along with other medicines like zidovudine, exactly as advised by the doctor. The quantity and frequency of the dose, and the duration of the treatment should neither be increased nor decreased without first consulting the doctor.
Zalcitabine should be taken regularly at about the same time every day. If you miss a dose, take it as soon as you remember it and then come back to the normal schedule. However, if you skip a dose, don't double the next one. Get your refills well in time so that you do not miss a dose in case you are not able to get a refill on time.
Follow the directions given on the label and in your prescription.
To make sure the medication is helping you, a blood test will be required at regular intervals. A liver function test may also be required from time to time. So, follow your visit schedule to the doctor and get all the tests done.
Zalcitabine changes into its active form (ddC) inside the body and hinders the activity of the enzyme reverse transcriptase needed by HIV to replicate its DNA. Thus, the virus is effectively prevented from reproduction checking its spread in the body.
Do not stop taking the medicine without first talking to your doctor.
Store the medication at room temperature. Keep it away from light, heat and moisture, and of course, children's reach.
Discard properly when no longer needed, or when expired. Do not flush down the toilet, nor pour into the drain. Ask your pharmacist or a local waste disposal company about the safe disposal of the drug.
