Medications and Drugs
Pharmacy Editor: Jay W. Marks, MD
GENERIC NAME: lamivudine and zidovudine
BRAND NAME: Combivir
DRUG CLASS AND MECHANISM: Combivir is an oral drug that is a combination of
lamivudine (Epivir) and zidovudine (Retrovir). It is used for the treatment of
infections with the human immunodeficiency virus (HIV). Lamivudine and
zidovudine are in a class of drugs called reverse transcriptase inhibitors that
also includes zalcitabine (Hivid) and didanosine (Videx).
During infection with HIV, the HIV virus multiplies within the body's cells.
The newly-formed viruses are released from the cells and then spread throughout
the body where they infect other cells. In this manner, the infection
continually spreads to new, uninfected cells that the body is continually
producing, and HIV infection is perpetuated. When producing new viruses, the HIV
virus must manufacture new DNA for each virus. Reverse transcriptase is the
enzyme that the virus uses to form this new DNA. Lamivudine and zidovudine block
the activity of reverse transcriptase and block the production of DNA and new
viruses. (Specifically, lamivudine is converted within the body to its active
form, lamivudine triphosphate, and zidovudine is converted to its active form,
zidovudine triphosphate. The active forms are similar to the naturally occurring
deoxycytidine triphosphate and thymidine triphosphate, respectively, chemicals
that are used by reverse transcriptase to make DNA. The reverse transcriptase
uses lamivudine triphosphate and zidovudine triphosphate instead of the
naturally-occurring deoxycytidine triphosphate and thymidine triphosphate for
making DNA, and these active forms of the drugs interfere with the activity of
reverse transcriptase.)
The effectiveness of either lamivudine or zidovudine when used alone may
decrease as the HIV virus develops resistance to the effects of the individual
drugs. By combining lamivudine and zidovudine, it is more difficult for the HIV
virus to develop resistance to therapy since it must develop resistance to both
drugs. As a result, Combivir is more effective than lamivudine or zidovudine
alone. Combivir does not kill existing HIV virus, and it is not a cure for HIV.
Combivir was approved by the FDA in September, 1997.
GENERIC AVAILABLE: No.
PRESCRIPTION: Yes.
PREPARATIONS: Tablets: 150/300 mg (lamivudine/zidovudine)
STORAGE: Store at 2-30°C (36-86°F).
PRESCRIBED FOR: Combivir is used, in combination with other agents, for the
treatment of HIV infection.
DOSING: For the treatment of HIV infection the recommended oral dose for
adults or children greater than 12 years of age is one tablet twice daily.
Combivir is administered without regard to meals since food does not affect its
absorption.
DRUG INTERACTIONS: Fluconazole (Diflucan), probenecid, trimethoprim (Trimpex)
and valproic acid (Depakote) reduce the elimination of zidovudine and therefore
increase the blood concentration of zidovudine. This can lead to increased side
effects from zidovudine.
PREGNANCY: Use of Combivir during pregnancy has not been adequately
evaluated.
NURSING MOTHERS: Use of
Combivir by nursing mothers has not been studied. HIV infected mothers should
not breast feed because of the potential risk of
transmitting HIV to an infant that is not infected.
SIDE EFFECTS: The most serious side effects of Combivir are a decrease in
blood cells, muscle pain (myopathy) or muscle breakdown (rhabdomyolysis), liver
enlargement and metabolic disturbance (lactic acidosis). Other side effects
include chills, rash, abdominal pain, nausea and vomiting, weight loss,
headache, cough and insomnia. Accumulation or redistribution of fat may also
occur.
Reference: FDA Prescribing Information
Last Editorial Review: 9/26/2005
Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
- Drug Interactions - Learn about potential drug interactions you may be exposed to. Drug interactions can occur with prescription drugs, OTC medication, vitamins, herbs, and supplements.
- Human Immunodeficiency Virus - Read about HIV (human immunodeficiency virus) causes, symptoms, signs, treatment, prevention, transmission, facts, testing, research (vaccine), statistics and AIDS (acquired immunodeficiency syndrome).
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