WHAT ABOUT DRUG RESISTANCE?

WHAT ABOUT DRUG RESISTANCE?

Many new copies of HIV are mutations. They are slightly different from the original virus. Some mutations can keep multiplying even when you are taking an ARV drug. When this happens, the drug will stop working. This is called “developing resistance” to the drug. See Fact Sheet 126 for more information on resistance.

Sometimes, if your virus develops resistance to one drug, it will also have resistance to other ARVs. This is called “cross-resistance”.

Resistance can develop quickly. It is very important to take ARVs according to instructions, on schedule, and not to skip or reduce doses.
HOW IS ZIDOVUDINE TAKEN?

The recommended dose of zidovudine for adults is 500mg to 600mg daily. Zidovudine comes in 100mg capsules and 300mg tablets. It is also available in liquid form.

Zidovudine is also available in Combivir and Trizivir. Combivir contains zidovudine and lamivudine. Trizivir contains zidovudine, lamivudine, and abacavir. For more information, see Fact Sheet 417 on Combivir or Fact Sheet 418 on Trizivir.
WHAT ARE THE SIDE EFFECTS?

When you start ART, you may have temporary side effects such as headaches, high blood pressure, or a general sense of feeling ill. These side effects usually get better or disappear over time. Some patients taking zidovudine continue to have nausea, vomiting, headaches and fatigue.

The most serious side effects of zidovudine are anemia, myopathy and neutropenia. These side effects are not common.

Anemia is a shortage of red blood cells caused by damage to bone marrow. If you get anemia, your health care provider might reduce your dose or switch zidovudine for another ARV. If the anemia is severe and you have to keep taking zidovudine, you may need a blood transfusion, or you might take the drug erythropoietin. For more information on anemia, see Fact Sheet 552.

Myopathy is muscle pain and weakness. There is no specific treatment for myopathy.

Neutropenia is an abnormally low number of neutrophils, the most common type of white blood cell. Neutropenia increases the risk of bacterial and fungal infections.