Which of the following is a first-line drug for the treatment of active tuberculosis?

Choice A reason: Temporary swelling and rash are not common adverse effects of topical acyclovir. This antiviral inhibits viral DNA replication with minimal local irritation. Allergic reactions are rare, and swelling or rash would suggest hypersensitivity, not a typical response to topical application for genital herpes.

Choice B reason: Numbness and tingling are not associated with topical acyclovir. These symptoms may occur with systemic antivirals or nerve-related conditions, but topical acyclovir acts locally on herpes lesions with minimal systemic absorption, causing primarily mild irritation rather than neurological symptoms like paresthesia.

Choice C reason: Insomnia is not a side effect of topical acyclovir, which has negligible systemic absorption. Systemic antivirals like oral acyclovir may rarely cause CNS effects, but topical application is confined to the skin, primarily causing local irritation, not systemic effects like sleep disturbances.

Choice D reason: A burning sensation is a common adverse effect of topical acyclovir when applied to genital herpes lesions. The drug’s vehicle or local tissue irritation during application can cause transient burning or stinging, which is expected and typically resolves, requiring patient education to ensure adherence.

Choice A reason: Dehydration is not a primary concern with intravenous dexamethasone, a corticosteroid. While corticosteroids can cause fluid retention due to mineralocorticoid effects, leading to edema, they do not typically cause dehydration. Monitoring fluid status is important, but hypokalemia is a more direct electrolyte imbalance associated with corticosteroid use.

Choice B reason: Hypoglycemia is not a common side effect of dexamethasone. This corticosteroid increases blood glucose levels by promoting gluconeogenesis and insulin resistance, potentially causing hyperglycemia, especially in diabetic patients. Monitoring for elevated glucose is more relevant than hypoglycemia, which is not typically induced by corticosteroids.

Choice C reason: Hyponatremia is less likely with dexamethasone, which has minimal mineralocorticoid activity compared to drugs like hydrocortisone. It may cause fluid retention, but significant sodium depletion is rare. Hypokalemia is a more prominent electrolyte disturbance due to potassium excretion induced by corticosteroid effects on renal tubules.

Choice D reason: Hypokalemia is a known side effect of dexamethasone, as corticosteroids enhance renal potassium excretion by stimulating mineralocorticoid receptors. This disrupts electrolyte balance, potentially causing muscle weakness, arrhythmias, or fatigue. Monitoring serum potassium levels is critical during intravenous administration to prevent complications from hypokalemia in patients receiving dexamethasone.