A nurse is caring for a client who has hydromorphone toxicity.
The nurse should anticipate a prescription for which of the following medications?

Choice A rationale

Tuberculosis is a bacterial infection primarily affecting the lungs, caused by *Mycobacterium tuberculosis*. Didanosine is an antiretroviral medication, specifically a nucleoside reverse transcriptase inhibitor (NRTI), and as such, it does not possess antimicrobial activity against bacterial pathogens like *Mycobacterium tuberculosis*. Therefore, it is not indicated for treating tuberculosis.

Choice B rationale

Human immunodeficiency virus (HIV) is a retrovirus that attacks the body's immune system. Didanosine is an antiretroviral drug that inhibits the replication of HIV by interfering with the reverse transcriptase enzyme, which is crucial for the virus to convert its RNA into DNA. This mechanism of action effectively reduces the viral load and improves immune function in individuals with HIV infection.

Choice C rationale

Bacterial meningitis is an inflammation of the meninges, the membranes surrounding the brain and spinal cord, caused by various bacterial species. Didanosine is an antiviral agent specifically targeting retroviruses like HIV. It does not have any direct antibacterial properties or efficacy against the common bacterial pathogens responsible for meningitis, thus making it an inappropriate treatment.

Choice D rationale

Syphilis is a sexually transmitted infection caused by the bacterium *Treponema pallidum*. The primary treatment for syphilis is antibiotics, particularly penicillin. Didanosine, being an antiretroviral medication, does not exhibit any treponemicidal activity and is ineffective against *Treponema pallidum*. Therefore, it is not used in the treatment of syphilis.

Choice A rationale: Persistent coughing with mucopurulent sputum suggests an ongoing respiratory infection or inflammation. Mucopurulent sputum indicates the presence of neutrophils and bacteria, often seen in bacterial pneumonia or tuberculosis. While significant, coughing alone is not an immediate life-threatening finding but rather a symptom requiring monitoring and further diagnostic follow-up to confirm the cause.

Choice B rationale: Joint pain in a patient receiving infliximab for rheumatoid arthritis may reflect an autoimmune flare or side effects of immunosuppression. Although uncomfortable and significant for quality of life, joint pain does not usually require immediate intervention compared to respiratory or infectious signs that may threaten life or transmission risk.

Choice C rationale: Anorexia, or decreased appetite, is a common systemic symptom in chronic infections like tuberculosis. It reflects the body’s inflammatory response and catabolic state but is a nonspecific finding. It requires addressing nutritional support but is not immediately life-threatening or requiring urgent intervention compared to active infectious disease signs.

Choice D rationale: Night sweats are a classic systemic symptom of tuberculosis caused by cytokine-mediated thermoregulatory dysfunction during infection. Although important in clinical suspicion, night sweats themselves do not necessitate immediate intervention but support the need for further diagnostic workup and infection control precautions.

Choice E rationale: An 11 mm induration on the purified protein derivative (PPD) test is considered positive in this patient due to immunosuppression with infliximab, which increases TB risk. The normal cutoff varies by risk factors, but 5 mm or greater is positive in immunosuppressed patients. This finding requires urgent follow-up to initiate treatment and prevent active disease and transmission, making it the most critical.