The nurse is providing counseling to a woman who is HIV positive and has just discovered that she is pregnant.
Which anti-HIV drug is given to HIV-infected pregnant women to prevent transmission of the virus to the infant?

Choice A rationale:

Rifampin Rifampin is an antitubercular drug that is effective against all strains of Mycobacterium tuberculosis. It works by inhibiting the synthesis of RNA in the bacteria, preventing them from reproducing. However, it does not typically cause a decrease in visual acuity.

Choice B rationale:

Ethambutol Ethambutol is an antitubercular drug that can cause ocular toxicity in the form of visual field changes. It is known to induce toxic optic neuropathy, which is quite common and can lead to a decrease in visual acuity. Patients on Ethambutol therapy are advised to report any changes in visual acuity or eye discomfort immediately to their healthcare provider.

Choice C rationale:

Streptomycin Streptomycin is an aminoglycoside antibiotic used in the treatment of tuberculosis. It works by inhibiting protein synthesis in bacteria. While it can cause side effects such as ototoxicity and nephrotoxicity, it is not typically associated with a decrease in visual acuity.

Choice D rationale:

Isoniazid Isoniazid is a first-line antitubercular drug that works by inhibiting the synthesis of mycolic acids in the cell wall of Mycobacterium tuberculosis. While it can cause peripheral neuropathy, it is not typically associated with a decrease in visual acuity.

Choice A rationale:

Zidovudine, also known as AZT, is a medication used for the treatment of human immunodeficiency virus (HIV) infection. One of the major dose-limiting toxic effects of Zidovudine is hematologic toxicity, which manifests clinically as anemia, neutropenia, and sometimes as platelet deficits with onset after several weeks of treatment. This hematologic toxicity is essentially a form of bone marrow suppression. Therefore, bone marrow suppression is the dose-limiting adverse effect of zidovudine therapy.

Choice B rationale:

Retinitis is not a known dose-limiting adverse effect of zidovudine. While zidovudine has a range of side effects, retinitis is not commonly associated with its use.

Choice C rationale:

Renal toxicity is not a known dose-limiting adverse effect of zidovudine. While zidovudine can have various side effects, renal toxicity is not typically one of them.

Choice D rationale:

Hepatotoxicity is not the dose-limiting adverse effect of zidovudine. While severe hepatomegaly with steatosis, including fatal cases, have been reported with the use of zidovudine, it is not considered the dose-limiting adverse effect. The dose-limiting adverse effect is more specifically related to hematologic toxicity, which includes bone marrow suppression.