- WHAT IS AZT?
- WHO SHOULD TAKE AZT?
- WHAT ABOUT DRUG RESISTANCE?
- HOW IS AZT TAKEN?
- WHAT ARE THE SIDE EFFECTS?
- HOW DOES AZT REACT WITH OTHER DRUGS?
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PrintAZT (Retrovir®), is a drug used for antiviral
therapy. It is manufactured by GlaxoSmithKline. AZT is also
known as azido-deoxythymidine, zidovudine or ZDV.
AZT was the first drug approved for the treatment of HIV. It
is a nucleoside analog reverse transcriptase inhibitor, or nuke.
These drugs block the reverse transcriptase enzyme. This enzyme
changes HIV’s genetic material (RNA) into the form of DNA. This
has to occur before HIV’s genetic code gets inserted into an infected
cell’s own genetic codes.
AZT?
AZT was approved as an antiviral drug for people with HIV infection.
There are no absolute rules about when to start antiviral drugs.
You and your doctor should consider your T-cell count, your viral
load, any symptoms you are having, and your attitude about taking
HIV medications. Fact Sheet 411
has more information about guidelines
for the use of antiviral medications.
If you take AZT with other antiviral drugs, you can reduce
your viral load to extremely low levels, and increase your T-cell
counts. This should mean staying healthier longer.
Because AZT was the first anti-HIV drug approved, it has been
studied more than any other drug. New drugs have been tested by
comparing them to AZT. And because there is more research on AZT
than on any other anti-HIV drug, it is prescribed the most often.
“Early treatment” with AZT was tested in people with
no symptoms of HIV disease. The study showed no benefit to taking
AZT. But AZT is used as part of combination therapy for people
who are exposed to HIV through a workplace accident (needlestick
or splash).
AZT greatly reduces transmission of HIV from the mother to
her child. It is given to HIV-positive pregnant women from the
4th month of pregnancy until
their baby is born, and to the newborn baby for 6 weeks.
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 antiviral drug. When this happens,
the drug will stop working. This is called “developing resistance”
to the drug. See Fact Sheet 414
for more information on resistance.
Sometimes, if your virus develops resistance to one drug, it
will also have resistance to other antiviral drugs. This is called
“cross-resistance”.
Resistance can develop quickly. It is very important to take
antiviral medications according to instructions, on schedule,
and not to skip or reduce doses.
HOW
IS AZT TAKEN?
The recommended dose of AZT for adults is 500mg to 600mg daily.
AZT comes in 100mg and 300mg capsules and in liquid form.
AZT is also available in Combivir and Trizivir. Combivir contains
AZT and 3TC. Trizivir contains AZT, 3TC, and abacavir. For more
information, see Fact Sheet 426 on
Combivir or Fact Sheet 427 on
Trizivir.
SIDE EFFECTS?
When you start any antiviral treatment you may have temporary
side effects such as headaches, hypertension, or a general sense
of feeling ill. These side effects usually get better or disappear
over time. Some patients taking AZT continue to have nausea, vomiting,
headaches and fatigue.
The most serious side effects of AZT are anemia, granulocytopenia,
and myopathy. Very few people have these side effects.
Anemia is a shortage of red blood cells caused by damage
to bone marrow. If you get anemia, your doctor might reduce your
dose or switch AZT for another antiviral drug. If the anemia is
severe and you have to keep taking AZT, you may need a blood transfusion,
or you might take the drug erythropoietin.
Granulocytopenia is a shortage of white blood cells
caused by damage to bone marrow. If it occurs, your doctor should
switch from AZT. It can be treated with a “colony stimulating
factor” called G-CSF, which stimulates the production of
white blood cells. But G-CSF is very expensive. Changing drugs
may be a better choice.
Myopathy is muscle pain and weakness. There is no specific
treatment for myopathy.
REACT WITH OTHER DRUGS?
AZT is more effective if taken with other antiviral
drugs.
AZT should not be combined with d4T (stavudine, Zerit®).
AZT’s side effects may be worse if taken with several
other drugs. Be sure your doctor knows about all the medications
you are taking.
Revised February
7, 2002
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New Mexico AIDS Education and Training Center
and the New Mexico Department of Health