A patient who has been taking isoniazid has a new prescription for pyridoxine. She is wondering why she needs this medication. The nurse explains that pyridoxine is often given concurrently with isoniazid to prevent which condition?

Choice A reason: Albuterol is a short-acting beta-2 agonist (SABA), with effects lasting 4-6 hours, while salmeterol is a long-acting beta-2 agonist (LABA), lasting up to 12 hours. This statement reverses their durations, making it incorrect, as albuterol is used for acute relief, not maintenance.

Choice B reason: Albuterol, a SABA, acts within minutes and lasts 4-6 hours, ideal for acute asthma relief. Salmeterol, a LABA, has a slower onset (20-30 minutes) and lasts 12 hours, used for maintenance. This pharmacodynamic difference in duration makes this the correct statement.

Choice C reason: Salmeterol’s effects last up to 12 hours, not 3-4 hours, and albuterol’s duration is 4-6 hours, not 12 hours. This statement inaccurately describes their pharmacodynamic profiles, as salmeterol is long-acting and albuterol is short-acting, making it incorrect.

Choice D reason: Albuterol’s rapid onset (within minutes) makes it ideal for acute asthma attacks, while salmeterol’s slow onset (20-30 minutes) makes it unsuitable for acute relief. This statement is incorrect, as albuterol, not salmeterol, is the first-line rescue medication for asthma exacerbations.

Choice A reason: Antiviral drugs are not solely for palliative care. They inhibit viral replication, reducing viral load and disease severity, as with acyclovir for herpes. While some provide symptomatic relief, many target specific viral processes, aiming for virologic suppression or cure, not just palliation.

Choice B reason: Antiviral drugs, like acyclovir, inhibit viral replication (e.g., DNA polymerase), but some, like chemotherapy agents, can affect healthy cells with high turnover, causing side effects like myelosuppression. This non-specificity is a key consideration, as it limits dosing and requires monitoring for toxicity.

Choice C reason: Antiviral efficacy does not depend on avoiding re-exposure. Drugs like oseltamivir reduce viral replication during active infection, but re-exposure may cause new infections. Prophylaxis or vaccination prevents reinfection, not the drug’s initial effectiveness, making this statement incorrect for antiviral therapy.

Choice D reason: Antivirals cannot be dosed to eradicate viruses without harming healthy cells. Their mechanisms, like inhibiting viral enzymes, often affect host cells, causing toxicity (e.g., nephrotoxicity with acyclovir). Dose limitations balance efficacy and safety, preventing complete viral eradication without side effects.