Trizivir (abacavir sulfate; lamivudine; zidovudine AZT) Tablet
The following drug information is obtained from various newswires, published
medical journal articles, and medical conference presentations.
Trizivir tablets contain three nucleoside analogues; abacavir
sulfate (Ziagen), lamivudine (Epivir or 3TC) and zidovudine
(Retrovir, ZDV or azidothymidine). This combination therapy has
been developed to simplify the dosing regimen for HIV patients. It
is available by prescription only and is not indicated for
pediatric patients. Severe hypersensitivity warnings have been
posted. Please note these warnings and notify a physician
immediately if signs occur.
For more information regarding studies done on the
bioequivalence of Trizivir and on numerous trials involving the
three components: abacavir sulfate, lamivudine and zidovudine, go
Wellcome and look under Clinical Pharmacology and Description
of Clinical Studies.
No adverse side effects were seen in pregnant women taking
zidovudine, however no data has been collected on the effects of
abacavir sulfate and lamovudine on pregnant women. As always,
pregnant mothers should consult their physicians carefully before
Antiretroviral Pregnancy Registry: To monitor
maternal-fetal outcomes of pregnant women exposed to Trizivir or
other antiretroviral agents, and antiretroviral pregnancy registry
has been established. Physicians are encouraged to register
patients by calling 1-800-258-4263.
The Centers for Disease Control and Prevention recommend
that HIV-infected mothers not breastfeed their infants to avoid
risking postnatal transmission of HIV infection.Zidovudine
is excreted in breast milk and abacavir has been found in the milk
of lactating rats. No data has been collected on lamivudine.
Mothers should be instructed not to breastfeed if they are using
Extensive hypersensitivity warnings have been posted concerning
the three components of Trizivir. If any hypersensitivity reactions
occur discontinue drug use immediately and consult your physician.
Severe and fatal reactions could be possible if use of Trizivir is
continued after a hypersensitivity reaction is observed. In
clinical trials approximately 5% of patients receiving abacavir
developed hypersensitivity reactions.
Frequently seen hypersensitivity reaction include, but are not
Abacavir Hypersensitivity Reaction Registry:
- skin rash
- abdominal pain
- loss of appetite/anorexia
- insomnia and sleep disorders
- depressive disorders
- nasal signs and symptoms
- musculoskeletal pain
To facilitate reporting of hypersensitivity reactions and
collection of information on each case, an abacavir
hypersensitivity registry has been established. Physicians should
register their patients by calling 1-800-270-0425.
To see a more complete listing of the warnings and reactions
associated with the use of Trizivir please go to:
Mechanism of Action
Abacavir: Abacavir is a carbocyclic synthetic
nucleoside analogue. Intracellularly, abacavir is converted by
cellular enzymes to the active metabolite, carbovir triphosphate.
Carbovir triphosphate is an analogue of
deoxyguanosine-5-triphosphate (dGTP). Carbovir triphosphate
inhibits the activity of HIV-1 reverse transcriptase (RT) both by
competing with the natural substrate dGTP and by its incorporation
into viral DNA. The lack of a 3 -OH group in the incorporated
nucleoside analogue prevents the formation of the 5 to 3
phosphodiester linkage essential for DNA chain elongation, and
therefore, the viral DNA growth is terminated.
Lamivudine: Lamivudine is a synthetic
nucleoside analogue. Intracellularly, lamivudine is phosphorylated
to its active 5-triphosphate metabolite, lamivudine triphosphate
(L-TP). The principal mode of action of L-TP is inhibition of RT
via DNA chain termination after incorporation of the nucleoside
analogue. L-TP is a weak inhibitor of mammalian DNA polymerases-a
and -B and mitochondrial DNA polymerase-y.
Zidovudine: Zidovudine is a synthetic
nucleoside analogue. Intracellularly, zidovudine is phosphorylated
to its active 5-triphosphate, zidovudine triphosphate (ZDV-TP). The
principal mode of action of ZDV-TP is inhibition of RT via DNA
chain termination after incorporation of the nucleoside analogue.
ZDV-TP is a weak inhibitor of the mammalian DNA polymerase-a and
mitochondrial DNA polymerase-y and has been reported to be
incorporated into the DNA of cells in culture. (From FDA Label)